Here’s a few dozen more icebreaker questions to use.

  1. What’s a scary sci-fi villain?
  2. If someone used you as an example of “what not to do”, what example would they use?
  3. What is your guilty pleasure song?
  4. What is your guilty pleasure movie / TV?
  5. What is your guilty pleasure meal?
  6. What is your guilty pleasure dessert?
  7. What is the first thing that you do when you wake up?
  8. What’s a good rom-com?
  9. What’s a good mystery movie?
  10. What’s a good comedy movie?
  11. What’s a good animated show?
  12. What’s a good animated movie?
  13. What is something that people should simply stop doing?
  14. What off brand item is better than its brand name counterpart?
  15. What was the first major news story you remember as a child?
  16. Who is your favorite female protagonist?
  17. You can’t time travel, but your phone has the internet from 5 years in the future. What do you search for first?
  18. What song would you put on a mixtape for Your Party?
  19. What song would you put on a mixtape for Getting Down?
  20. What song would you put on a mixtape for Cooking?
  21. What song would you put on a mixtape for Cleaning?
  22. What song would you put on a mixtape for Your Road Trip?
  23. What song would you put on a mixtape of TV show theme songs?
  24. What’s your favorite snack?
  25. What type of doughnut do you like?
  26. What’s an absurd moment in an otherwise serious movie?
  27. If you had to live in a world alongside one supernatural class of villains (zombies, vampires, etc.) which would it be and why?
  28. What’s the first video game you remember playing?
  29. What’s the first TV show you remember enjoying that wasn’t intended for children?
  30. What Disney movie have you watched the most (or at least a lot)?
  31. What’s a Disney memory you have?
  32. If you could read a book again for the first time, what would it be?
  33. What are you boycotting til the day you die?
  34. Without looking it up, what would you expect to buy at a “package store”?
  35. What looks fun in movies, but in real life is miserable?
  36. What’s a show that never had a bad episode?
  37. If it turns out that one species of animal has been aliens spying on Earth the whole time, what animal do you think it is?
  38. What do you consider “simple pleasures of life”?
  39. What are the worst answers to the interview question “where do you see yourself in five years”?
  40. What is a place you will never go again?
  41. If animals could talk, which would be the most rude?
  42. In the WFH era, which coworker that you haven’t already met would you most like to meet IRL?
  43. What made you smile this week?
  44. What’s a song that will never get old to you?
  45. What problem is often overlooked in apocalyptic movies/TV shows that could kill?
  46. What was cool when you were young but isn’t cool now?
  47. What seems harmless but could actually kill you?
  48. If you could have an unlimited supply of anything other than money, what would it be?
  49. What’s a band you want to listen to more of?
  50. How many unread emails do you have in your work inbox?
  51. How many unread text messages do you have on your phone?
  52. What was the last time you did something for the first time?
  53. What album has no skips?
  54. If you could erase all memories of listening to a song so you could listen to it for the first time but you lose all memories associated with it, what song would you pick?
  55. If all animals were horse sized, which would be the most majestic to ride into battle?
  56. What cartoon character would make a good CEO?
  57. What’s one of your favorite sandwiches?
  58. What’s one of your favorite soups?
  59. What’s one of your favorite drinks?
  60. What’s a song lyric that you like?
  61. Who was one of the nicest people you have met?
  62. What’s a word or phrase used to mean their opposite? (for example, using the word “literally” to literally mean “figuratively”)
  63. Create a new Crayola color name.
  64. What would you store in a fanny pack?
  65. What’s an out-of-character thing you’ve done recently?
  66. What fast food restaurant do you like?
  67. What’s your pizza order?
  68. What’s your Uber rating?
  69. What would your Uber rating be as a DRIVER?
  70. Halloween is approaching, what monster would you prefer getting chased by?
  71. What is your favorite “old school” device/gadget?
  72. What’s something you can easily eat 6 of?
  73. What’s a sequel that came out at least 10 years after the previous movie that you enjoyed?
  74. In your opinion, what’s an underrated movie?
  75. What’s the best trip (traveling wise) you ever had?
  76. If you were a robot what would you say to convince others you aren’t?
  77. What’s a slack channel that has some good content?
  78. What’s something that you’re looking forward to? Eg. a new show/movie/album/song, a phone/computer/tv/car/apartment upgrade, a vacation/holiday/birthday, the end of the day, midday nap/snack-break
  79. What movie could you watch over and over without getting tired of it?
  80. What’s a song lyric you always get wrong?
  81. What’s an overrated movie?
  82. What’s one of your go to subredits?
  83. What would you blog about?
  84. What’s a weird or bad roommate situation you’ve had?
  85. If you were a professional burglar, what would be your calling card? (Think: The Wet Bandits)
  86. What’s something you’re snobby about?
  87. What are your Turkey Day plans this year?
  88. What did you buy during Black Friday (the day or weekend after Thanksgiving)?
  89. What’s something you’ve only started to like after college?
  90. What’s a discontinued food or beverage item you wish would return?
  91. What’s a strong opinion you have about something that’s not important?
  92. What’s a movie you think I haven’t seen that Josh would like? (The “I” in this scenario is whoever is asking the icebreaker question)
  93. What’s something you are an expert in?
  94. What types of shoes do you wear?
  95. What company or team reference would make a good band name?
  96. What’s a skill you would like to learn in the new year?
  97. Design a movie marathon. Minimum 4 movies.
  98. What would your New Year’s resolution be? (If you have one, then say it, if you don’t then make one up!)
  99. What’s a movie you haven’t seen in a while that you need to rewatch?
  100. What’s something that you thought everyone else did but learned later in life that it was just you/your family/your community?
  101. What is a new skill you learned?
  102. What is a good late night driving song?
  103. What’s a fact that you still don’t believe?
  104. What’s a movie that you enjoy that wouldn’t be made today?
  105. What’s a good non-super-hero movie from the past 10 years?
  106. Who was one of the best teachers you had?
  107. Should hexagons be drawn “flat-top” or “pointy-top” ?
  108. What’s your favorite Disney character?
  109. What’s a favorite new food/restaurant you’ve discovered recently?
  110. What’s the most magical place on earth?
  111. What’s the worst place on earth?
  112. Which would you give up for rest of your life: tacos or pizzas?

Previous posts

Christmas, Recipe comments edit

Grammy’s Christmas Eve gravy with lobsters is one of my favorite parts of the holiday season. Plan for 1 lobster per person, with maybe an extra lobster or two for leftovers. Any excess gravy (or lobster) can be reserved for bisque.

Ingredients

  • 6 lobsters (between 1-1/4 to 1-1/2 pounds each)
  • 8 cans of tomato puree
  • 8 cans of water (use the empty puree cans)
  • 1 large onion
  • 4 to 8 large cloves of garlic
  • Olive oil
  • Salt
  • Itallian seasoning to taste
  • 1/2 pound thick spaghetti

Make the Gravy

  1. Mince & crush garlic
  2. Dice onion
  3. Heat LARGE pot with enough oil to cover the bottom
  4. Add onion, garlic, salt, Italian seasoning
  5. Cook until shimmering (5 to 10 minutes)
  6. While waiting for that to cook, open the 8 cans of tomato
  7. Add tomato puree and water
  8. Cover and bring up to a simmer
  9. Uncover and let simmer for ~2 to 4 hours

Make the Lobster

This can be a little messy. I normally get two large disposable baking pans to hold and organize the lobster parts. A dishtowel that you’re not terribly attached to can be used when holding the lobsters’ claws and knuckles to avoid getting knicked by the sharp bits.

  1. Dismember the lobsters
  2. Using a dishtowel, grab the arms and twist them off the body
  3. Using the same dishtowel, break the knuckles off the claws by snapping perpendicular to how the claw bends
  4. Using a sharp knife that doesn’t have a heal, cut the tail off the body. The back end of the blade can be slid between the shell to start the cut safely.
  5. Using the same knife, cut the tail at the third section from the front
  6. Grab a cleaver or other heavy knife, knotch a slit in the back of the claw, once the blade is lodged far enough in, you can twist the knife and crack off the end of the claw. The end typically won’t come all the way off, but that’s fine. You’re just looking to make it easier to get at the meat once it’s cooked. Don’t forget to take the rubber bands off the claws at this point.
  7. Using kitchn sheers, cut lengthwise down the knuckle
  8. Dump everything into the boiling (or near boiling) gravy
  9. Let cook for 15 minutes, or until the shells all turn red. Over cooking isn’t too big of a deal.

Serving

As per tradition, each person must eat at least two plates of spaghetti. After that it’s a free-for-all grabbing whatever lobster you can.

Recently, I’ve been doing a small plate of spaghetti and serving only the claws and tails. I reserve the body and knuckle meat for bisque.

Christmas, Recipe comments edit

Leftover lobster and gravy from Christmas Eve can be made into a tasty bisque. This soup can be made in stages, with each componenet refrigerated. When you are ready for the soup, combine and let everything come up to temp, cooking the fresh seafood.

Ingredients

  • 4 - 6 quarts lobster gravy
  • Seafood
    • leftover lobster (pick through the bodies and knuckles)
    • 1 pound shrimp (cut them in half if they are large)
    • 1 pound scallops
  • Bechemel
    • 1 stick butter
    • 4 tablespoons flour
    • 2 cups milk
  • Splash of cognac or white wine
  • Salt and peper to taste

Make the Béchamel Sauce

This can be done the night before and kept in the fridge until needed.

  1. Melt the stick of butter with 4 table spoons of flour to make a roux
  2. Slowly incorporate 2 cups of milk

Reserve Lobster and Gravy

  1. Reduce 6 to 8 quarts of lobster gravy (lobster removed) by about 1/3 so you have 4 to 6 quarts of lobster gravy remaining.
  2. Pick through the remaining lobster to get leftover meat. The bodies and knuckles are the best source after Christmas Eve dinner.
  3. Combine lobster and gravy
  4. Refrigerate over night if you don’t want to make the bisque right away

Assemble the Bisque

  1. Bring the béchamel sauce back up to temp
  2. Slowly incorporate the tomato sauce into the béchamel
  3. Mix in one laddle full at a time and stir
  4. Once three or so laddles are in, then you can dump the rest in
  5. Add the uncooked seafood
  6. Bring to temp
  7. Add splash of cognac or white wine
  8. Add salt and pepper
  9. Simmer until thoroughly cooked.

A few months ago I posted a list of my Question of the Day icebreakers. Here are some new ones I’ve used since then.

  1. Any plans for the holiday break?
  2. Each Planet Earth installment takes about 2,089 film shooting days, or just over 5.7 years non-stop. If you were tasked with being the editor for one animal of your choice to present a story to the Planet Earth audience, which animal (or even climate) would you choose?
  3. Favorite Movie
  4. Fun animal fact!
  5. If at the end of your life your stats were displayed what is your most impressive stat?
  6. If someone used you as an example of “what not to do” what example would they use?
  7. If you could pick a fictional character for a roommate, who would you choose?
  8. If you could pick up a new skill in an instant what would it be?
  9. If you got to pick the one person that would be the ambassador for the human race to meet the aliens, who would you choose?
  10. If you had a PAST ONLY time machine where/when would you go to?
  11. If you had to teach a class, what class would you teach?
  12. If you were to play some sort of table top RPG, what alignment would you be? (http://easydamus.com/alignment.html)
  13. If you were to play some sort of table top RPG, what class type would you be? (http://easydamus.com/alignment.html)
  14. If your life were a song who would sing it?
  15. In 40 years, what will people be nostalgic for?
  16. Liam Neeson has kidnapped you! What one person (real or fictional) would you want to try and save you?
  17. Name a “children’s movie” that you think is too scary for kids
  18. Name a fun prank you’ve played on someone.
  19. Name an actor whose hair you wish you had?
  20. Other than no longer having to stand during standup, what’s a small silver lining of working from home?
  21. What Christmas song will make you change the channel or turn off the radio if it comes on?
  22. What Question of the Day do you want to ask in the New Year? (yes, this question is both a cop out and an attempt to get more questions)
  23. What band/singer do you refuse to believe people could hate?
  24. What can you brag about because of somewhere that you’ve worked?
  25. What candy do you hate?
  26. What did you do during the end of year break?
  27. What did you miss: What movie that “everyone has seen” have you not seen?
  28. What do you put on in the background when you really want to focus?
  29. What do you say in place of a swear instead of just swearing?
  30. What do you think is humanity’s greatest achievement?
  31. What entirely instrumental song do you really enjoy?
  32. What has caused you to quit a job?
  33. What is a stand up comedy bit that you like?
  34. What is an unnecessary and expensive item that you are extremely tempted to buy right now?
  35. What is the creepiest thing/occurrence you have ever witnessed
  36. What is your “never again” brand item store or restaurant ?
  37. What is your favorite color to wear?
  38. What is your favorite sport to watch? If you don’t like watching sports, take the question as broadly as possible.
  39. What is your favorite poem?
  40. What is your idea of a perfect Sunday afternoon?
  41. What made up “holiday” theme do you want Josh to use for his Zoom background?
  42. What merit badge would you like to earn?
  43. What moment from your childhood do you think is a good indicator of how you were gonna turn out?
  44. What movie is better the second time watching it?
  45. What movie were you excited to watch but was a disappointment?
  46. What pets did you have growing up?
  47. What song do you know all the words to? (or at least most of the words)
  48. What toy did you always want as a kid, but never had?
  49. What useful emoji is missing from your company’s Slack emojis?
  50. What’s a favorite holiday movie? (Any holiday will do)
  51. What’s a gift that you’ve given someone that you’re proud of?
  52. What’s a holiday candy that you look forward to? (any holiday)
  53. What’s a random historical domino effect that you absolutely love?
  54. What’s a scary sci-fi villain?
  55. What’s something that made you feel old?
  56. What’s something you romanticize? (a time period? a subculture? a place?)
  57. What’s the first thing you do when you get home from a long trip?
  58. What’s your “goto” joke?
  59. What’s your New Years BLANK (Resolution, Plan, Goal, Hope, Expectation, etc)
  60. What’s your drink of choice? (Either alcoholic or non.)
  61. What’s your favorite Summer Olympics sport?
  62. What’s your favorite day of the week and why?
  63. What’s your favorite mask?
  64. What’s your favorite tea/coffee?
  65. What’s your go to bagel order?
  66. What’s your go-to diner order?
  67. What’s your perfect sandwich?
  68. When did you almost turn into Batman?
  69. When did you like the movie more than the book
  70. When does it begin to feel a lot like Christmas for you? (If you do not celebrate Christmas, replace with any other holiday. If you do celebrate Christmas and would prefer to substiture for another holiday, please do.)
  71. Where’s your favorite place to nap?
  72. Which Super Smash Bros character would you be?
  73. Which harry potter character are you?
  74. Who was your role model growing up?
  75. Without looking it up, how do you pronounce kubectl”?”
  76. You are an alien. Your alien comrades have the opportunity to create a crop circle once a human year. What is your chosen design for the year 2020?
  77. You are hiring someone to create a fake athletic profile for your child that will be used in your child’s college application to USC. What sport do they play?
  78. You win a contest and the prize is the privilege to add another person to Mt. Rushmore. Who are you adding?
  79. You’ve just won the lottery and are now worth millions. What do you do on Monday?

woodworking comments edit

I’ve been trying to get into woodworking for the past few months. Most of my resources have been YouTube videos and reddit. I’m compiling a list of the channels that I go to regularly and enjoy.

  • Woodworking for Mere Mortals has a lot of videos focusing on the “weekend woodworker” that doesn’t have a lot of tools, shop space, or time. Lots of great intro videos for how to use tools, what you really need to get started, and what projects you can tackle. Steve also has a woodworking class for $150 that has very detailed project videos and plans.
  • DIY For Knuckleheads. Lots of great project videos that feature beginner friendly techniques and how to make great use out of cheap or free wood. Great tip knackers!
  • Stumpy Nubs has a lot of how to’s and other beginner friendly content. Their “cool tool” series is great too.
  • Bourbon Moth has professional level project videos (as in they are mostly commissioned projects that he’s working on). His series on cabinet building is really good. He also has a 5 part series on building a boat. Recently he’s added a cocktail video each month.
  • Wood Work Web is mostly short videos focusing on either a series of useful tips or a specific technique.
  • Fisher’s Shop has a lot of project based videos. Most projects feel like they can be done by a beginner stretching from their comfort zone. Plus the outtakes at the end are a lot of fun.
  • Rex Kruger. This channel goes into a lot of details on hand tools, especially planes. Rex has great information on building up your workshop (and bench) to make you successful using hand saws and planes. He also has lots of recommendations on how to do things inexpensively and where and when you should spend the money. This includes stuff like how to buy an inexpensive plane and tune it to work well.
  • 3x3Customhas a lot of really cool project builds. She’s definitely not a beginner but her builds feel accessible.
  • April Wilkerson’s has some great videos on shop organization. She has a lot of videos on detailed furniture and deck builds but I really like the way she thinks about organization and packing in as much functionality to her shop storage as possible. I want her miter saw stand.
  • Blacktail Studiodoes a lot of high end table builds.

After the registers and the ALU, the program counter module was pretty easy. It is a 74LS161 4-bit binary counter connected to a 74LS245 8-bit transceiver. As with the other modules, the transceiver is only there to easily control reading or writing to the bus.

Using a binary counter IC to build a program counter may seem like cheating, but there’s no reason to make everything harder than it needs to be. The counter’s output and input are wired to the transceiver, the enabled pin is put high, connect the clock, and you’re good to go…

Well, that’s what the instructions said. Whenever I tried to run the counter it kept flashing “one”. After a few seconds of feeling crushingly defeated on what was supposed to be the easiest build of the project, I thought it felt like the counter was being constantly reset. I looked at the chip’s data sheet and saw that pin 1 is the clear pin. We hadn’t wired it to anything so it was floating. The pin is inverted, so I tried tying it high. Lo and behold, the counter now works.

I still need to wire up some permanent lights for the module. The ones in the video are part of the pack of lights I wired up for quick testing last time (or the time before that… sometime). They have resistors built in and just have a pair of pin Dupont connectors on the bottom so I can easily plug them in anywhere I want.

42 + 7 = 49

Now that I have two registers to store whatever (8-bit) values I want in them, what next? Let’s add them together! (Or subtract them).

The ALU

The ALU reads directly from the A and B registers and computes the sum of those two values. It bypasses the bus and reads directly from the registers, whether or not they are set to output their values. The ALU has two modes, add and subtract.

In subtract mode (when the control line is brought high), it subtracts the value in register B from register A. Subtraction works by negating the output of the B register and then adding that negative number to A. Two’s Complement is used to represent a negative number in binary. This pretty much boils down to flipping all the bit and then adding one. Eight XOR gates are used to flip the bits (the subtract signal is the other input to the gate) and then add one by setting the carry bit on the adder high. The carry bit is normally used when using multiple 4-bit adder chips together to add 8 bits together (or 12 or 16… etc).

Building and Debugging

So far this is has been the most complicated part of the computer to build. This is purely because of the number of connections to be made and how much they overlap. If you’re off by one pin for one wire the entire output is messed up and you have to wade through all the criss crossing wires to figure out what is wrong. The problem gets worse when you have multiple wires in the wrong spot… which is what happened to me.

I learned two useful approaches to this problem

  1. Write out a table of all of the connections
  2. Use a multimeter to test for voltage levels in addition to continuity

Tabling Connections

In order to know which if a wire is connecting the wrong pins on two IC’s, you need to know which are the right pins. So after blindly staring at the forest of wires, I went back to the pin outs of the IC’s and wrote a few tables to track what I should expect to be where. I did them by hand in a notebook, but this is essentially what I have.

The A Input

The A register is simpler than the B register since it connects directly to the adder and does not need to be negated.

A Register Bit A Transceiver Pin Adder Pin Name Adder Pin
8 2 A4 Left 12
7 3 A3 Left 14
6 4 A2 Left 3
5 5 A1 Left 5
4 6 A4 Right 12
3 7 A3 Right 14
2 8 A2 Right 3
1 9 A1 Right 5

This basically just tells me that if I think I’m having an issue with the most significant bit in the A register (bit 8), then I need to check to see if the wire from the transceiver’s second pin connects to the twelfth pin on the left adder. Once I run down all the pins combinations to make sure that they are correct, I can be confident that the register is wired up correctly and move on to the B register.

The B Input

As alluded to above, the B register is a touch more complicated because it goes through a set of XOR IC’s as well.

B Register Bit B Transceiver Pin XOR Pin Name XOR Pin
8 2 A4 Left 12
7 3 A3 Left 9
6 4 A2 Left 4
5 5 A1 Left 1
4 6 A4 Right 12
3 7 A3 Right 9
2 8 A2 Right 4
1 9 A1 Right 1

The other input pins on the XOR chips were easy and didn’t really require a complex table. All of the B pins were connected to eachother and then the carry in bit on the rigth adder

Pin Name XOR Pin
XOR B4 Left 14
XOR B3 Left 10
XOR B2 Left 5
XOR B1 Left 2
XOR B4 Right 14
XOR B3 Right 10
XOR B2 Right 5
XOR B1 Right 2
Adder Carry In 7

And then the output of the XOR chips feeds back into the two adders

B Register Bit XOR Pin Name XOR Pin Adder Pin Name Adder Pin
8 Y4 Left 11 B4 Left 11
7 Y3 Left 8 B3 Left 15
6 Y2 Left 6 B2 Left 2
5 Y1 Left 2 B1 Left 6
4 Y4 Right 11 B4 Right 11
3 Y3 Right 8 B3 Right 15
2 Y2 Right 6 B2 Right 2
1 Y1 Right 2 B1 Right 6

One of the bigger mistakes here is that I wired the left XOR to the right adder. Not sure why I was so certain that was the right thing to do at the time but I did it consciously and certain that it would work out.

Adder Output

And now all that we need to do is wire the adder outputs to the transceiver.

Summation Bit Output Transceiver Pin Adder Pin Name Adder Pin
8 2 Left Σ4 Left 11
7 3 Left Σ3 Left 15
6 4 Left Σ2 Left 2
5 5 Left Σ1 Left 6
4 6 Right Σ4 Right 11
3 7 Right Σ3 Right 15
2 8 Right Σ2 Right 2
1 9 Right Σ1 Right 6

Using a Multimeter

The most straightforward way to use the multimeter to verify the connections is to use the continuity feature:

  1. Turn on the multimeter
  2. Put the red lead on one pin
  3. Put the black lead on the pin you hope it’s connected to (this is where the charts come in handy)

If you hear a tone, then the wiring is good. If you don’t, then you found a problem. Move the black lead to other pins to determine which pin the other end of the wire is connected to. Even if there was a tone, it may be useful to place the black lead on other pins to check for a short. This would mean that another wire connected to this IC is incorrect.

The upside of this approach is that it is simple. The downside is that it requires testing every connection. This is a pretty simple layout and it has upwards of forty connections to check. Another option is to do voltage reading to test which connections have voltage running through them. This is essentially the same as hooking up an LED in parallel to each of the pins to see its output. Set the multimeter to 5v DC setting, put the black wire to ground, and then put the red wire on the IC pin. I like to use alligator clamps coming out of the multimeter connected to jumper wires. That way the wires can be plugged directly into the breadboard and you can monitor voltages as the state changes.

Output

The final component here is wiring up LED’s. I decided it would be easiest to read the output if I made more LED strips that could plug into the breadboard with headers. I’ve improved on the original design by using LED’s with with the resistors built in. This reduces the amount of soldering I need to do and makes the result a little more compact. Speaking of which, I also used 3mm LED’s instead of the original 5mm.

leds_back.jpg

leds_front.jpg

led_back.jpg

led_front.jpg

I’ve finished the registers for y project of building an 8-bit computer using TTL chips. I have built two general purpose registers (an “A register” and a “B register) as well as the instructor register for the computer. This step took a lot more time than the clock module. The main difficulties were cutting the wires to the correct size and then after that the thing just didn’t work. I couldn’t store or transfer any data.

What is a Register?

So what exactly did I build in the past few weeks? The computer I’m working on will have a certain amount of RAM to store information during the execution of a program. This information is both the data in the program as well as the program itself. For example, I can write a program that will add the numbers 2 and 4. The values 2 and 4 will be stored in RAM when the program is loaded into the computer. In addition to that, the program itself will be stored in memory. In a modern computer, the program would be stored on the hard drive, but it would eventually be loaded into RAM before it executes, and the data would probably be entered by a user. My computer won’t have either a hard drive or any form of user input. It will all just be stored directly in RAM.

Following the 2 plus 4 example, my computer can’t operate directly on the data in RAM. It can only add (or subtract) numbers that are stored in the registers. This means that we’ll need to copy the data from their location in RAM into either the A or B register. Once there the arithmetic-logic unit (the next part of the build) can operate on them. Basically, the register is short term storage for data being used very soon.

There are three operations you can do with a register:

  1. Write to it
  2. Read from it
  3. Clear it

Normally, you can’t easily inspect the data currently in the register. That would be boring and make it super hard to understand what’s going on at any given time in the computer. These registers have 8 red LED’s that will show the current state of the register.

Transferring data from one register to another (or to another part of the computer), that data is written and then read from the bus. The bus is pretty simple component that wires all the components together using 8 parallel input/outputs. Coordination is required so that only one thing is writing to the bus at a given time and that the component that wants that data is reading from it. For now that’s done manually, but wiring in that logic will be an important part of what makes this a computer.

Cutting Wires

Last time, I built the clock module for my 8-bit computer and I had a hell of a time cutting and stripping the wires just right. I could reliably cut the wires the right length, but then I couldn’t take off exactly 0.3” of insulation on either side using my strippers. I had two options: get good or buy more reliable strippers.

I went with the latter and picked up a set of Knipex wire strippers. These things are amazing. Set the length to strip, insert wire, pull trigger, repeat. The exact right amount is stripped each and every time. No worries about setting the right gauge wire, it auto adjusts. Pure joy to work with after fumbling around last week. I can now complete wiring tasks in minutes that would take hours without them.

wire_strippers.jpg

They are a little on the pricey side but they will save me so much time and effort that they are worth it. I’d highly recommend them if you can afford it.

The Build

ics.jpg

Each register uses :

  • 2 4-bit 74LS173 (register)
  • 1 8-bit 74LS245 (transceiver)

The remaining transceiver, OR gates, and adders in the picture will be used for the ALU.

The register chips are 4 bits each, which is why two are needed to store 8 bits total. They are wired together (clocks, read signal, output signal, etc) so that they can be used as a single logical unit. They are wired to always output their data so that we can see their state in the LED’s. That’s why the transceiver is needed to toggle writing that state to the bus when the computer needs to read from the register.

assembly_01.jpg

Each breadboard will be dedicated to a register. The top two will be the A and B registers, the bottom one will be used for the instruction register. The top two will be on the right side of the computer, the bottom one will be on the left. The transceiver chip will need to be connected to the bus (which will be in the middle) so it will be convenient to have that as close to the bus as possible (just to avoid messy wiring). Other than that, the three registers will be identical

assembly_02.jpg

Here we can see the connections keeping the pairs of register chips in sync with each other. The white wires (on the bottom) will be used as the clock input, the yellows are signals to read or clear data.

assembling_register.gif

The rest of the work is to just wire up the 8 channels connecting the registers and transceivers.

LED’s

After wiring everything up and testing it by trying to read off of a mocked out bus … Nothing worked.

I spent hours following the video checking and rechecking my connections. Everything looked right. Reading r/beneater had a lot of posts about how important resistors are to the project despite being largely omitted from the videos. So I tried adding some in series to the LEDs to see if it would make a difference. Yes it did! Everything works now (well mostly, I still had a few wires crossed).

Now my question was: how do I want to lay out the LED’s and resistors? There’s not a lot of space when it’s just the LED’s, how am I supposed to cleanly sneak eight resistors in? My first attempt was to wire one resistor up in parallel with all of the LED’s. After checking with Reddit, it became apparent that the brightness of the LED’s would fluctuate depending how many were turned on at any given time. That didn’t sound great so back the drawing board.

I thought I could solder a row of male headers to some protoboard and then add the eight LEDs and resistors. I’d need to add a female header on the side to connect it to ground. This felt like it was just about in my skill set, so I gave it a try.

I figured I’d make four of these for the three registers and the ALU. The first step was to cut the protoboard down to size and then sand the edges so they were no longer sharp.

protoboard_top.jpg

I cut the first one by scoring it with a razor blade and then snapping the ends off and then filing it down by hand. It took a while but in the end I had a nice result. Too bad I didn’t account for all the space I needed so I cut that one too small 🙁. It was late so I tabled it for the next day when I needed to break out the Dremel for another project anyway. This time I quickly cut the ends with the Dremel and then used the tool to do a first pass on the filing. I still finished it up by hand, but it was much faster.

protoboard_side.jpg

Turns out that the coaster my in-laws brought me back from a trip a few years ago is the perfect size to hold a PCB. I used that as a base and then filed the sides down to be nice and smooth.

led_strip_back.jpg

It took some trial and error to figure out the exact best way to solder everything in place. First I soldered two 4 pin male headers to the bottom of the board. They were spaced so they’d fit directly into the breadboard and connect to the registers.

led_strip_front.jpg

Next I placed the LED on the top of the board and bent the anode lead back up through the board to solder to the top of header. This may have been easier if I had done it first and then soldered in the headers.

led_strip_side.jpg

The cathode leads were then soldered to a resistor that was placed at an angle behind it. The angle allowed me to line up all of the resistors and just solder them together in a line leading to the female header on the end.

This mostly worked (I had a bad LED in the middle I had to swap out) but took me all day to do the soldering and testing for one LED strip. I could probably do the second strip a little faster now that I worked out some of the kinks. Instead of tackling that project, the next day I woke up and bought a few packs of LED’s with resistors built in. This would at least let me make progress in my tests without having to solder everything first. And maybe I can come up with a better plan.

I bought two types of LEDs. One kind has the resistor directly in the housing. I bought the mixed bag of colors as well as another hundred each of the reds and blues. These are 3mm instead of the 5mm ones I already had. Worst case scenario, I can work them into the same type of LED strip but have it take up less space and not have to solder in an additional resistor. The other type has the resistor soldered to the anode lead in a long wire. I got the mix pack for these as well, twenty each of white, red, blue, green, orange, and yellow. To simplify testing, I crimped Dupont connectors to the ends of a bunch of these in groups of four.

leds.jpg

And with that, I was able to test all of the registers and bus at the same time.

clock_module.jpg

I recently picked up Ben Eater’s 8-bit computer kit. The entire walk through for Ben’s computer can be found on youtube. The idea is to build a fully functioning 8-bit computer entirely on a breadboard. This should be a great learning experience for me considering I’ve never built anything particularly complicated in electronics. The first step is to create the clock module that powers the rest of the computer. The clock he’s designed has some interesting features

  1. Speed control using a potentiometer
  2. Step through mode - the clock advances when you manually press a button
  3. A circuit to switch between these two modes
  4. Halting the clock by setting the halt line high

This is step 1 of the clock module, the variable speed portion. It uses a 555 timer to produce the square wave that powers the LED. That LED is eventually going to be removed from the board when the entire module is done, which is why it hasn’t been cut down.

Ben’s Video

The clock kit comes with pre-cut jumper wires that you can use. The drawback to them is that you can’t control the color for each length of wire. So I dug into the second kit to pull out the spools of 25 foot colored wires. I figure if I start with those wires now then the color coding will be consistent for the entire project. Not only that, but the red wires will be the same shade for the entire time.

That said, my biggest difficulty so far has been gettin’ gud at trimming the breadboard wires. Ben’s computer winds up being very neat and orderly with the wires. I’m hoping to get something close to that. I’ve tried breaking out my calipers to start measuring every wire I cut. That’s helped a bit. I’ve also tried bending the wires across the edge of the breadboard. I’ll keep it up and jot down any more notes as I try new methods.

After several hours of practice, I think I have a system.

  1. Cut a length of wire and strip some off the end (really doesn’t matter how much)
  2. Use the bare part as a grip as you pull off the remainder of the insulation
  3. Put the wire into the end of the breadboard, N-1 from the edge, where N is the number of breadboard holes you need the wire to travel.
  4. Bend the wire down 90 degrees exactly where it comes out of the breadboard (this ensures you leave the exact right amount of bare wire to go into the breadboard)
  5. Angle the rest of the wire going off the breadboard
  6. Cut a piece of insulation the same length as the distance from where the wire is placed in the board to the end of the breadboard
  7. Slip that insulation back on to the wire
  8. Bend the remaining bare wire 90 down, using the edge of the board as a guide
  9. Trim the excess wire just above the bottom of the breadboard

If you need a bunch of wires at once, measure out the right length past the edge of the breadboard and leave that piece of wire in. Then use that as the guide for other pieces you need to cut. There are eight holes at the bottom end of the board, so you can do eight wires pretty quick.

I used the above method to cut the wires for the rest of the work:

Manual Clock Advance

Ben’s Video

Debounced Switch

Ben’s Video

Switching Between Inputs

Before I got started with this slightly more complicated step, I sorted and labeled the chips:

chip_cheat_sheet.jpg

High tech, I know!

Ben’s Video

Today’s build was fun. It took most of the day (I really need to get better at cutting wires to length), but I did a lot of other things in there like make dinner and watch an episode of Better Call Saul.

For all of the details on how this works, I recommend checking out Ben’s youtube videos. He goes into more details than I could.

Since we started working remote I’ve been asking my team 1 “Question of the Day” during standup. I started by posing the question at the start of the meeting, but have since switched to asking before the meeting. This gives people some time to come up with better answers. I try to avoid asking for “favorites” because that can put too much pressure on people to come up with the right answer. So instead of “What’s your favorite movie?” (which is definitely on the list) I’d ask “What’s a movie you’ve enjoyed recently?”

  1. As a child, what did you want to be when you grew up?
  2. As a kid, what was your go-to routine for a sick day?
  3. Besides insects and spiders, what animals annoy you the most?
  4. Best movie that would be improved if all characters were muppets except one. Name the non-muppet character.
  5. Brewsters Millions: If you had to spend $10 M in one month, how would you do it? Like the movie, you can’t have anything to show for it at the end of the month.
  6. Favorite Movie
  7. Favorite Sci Fi
  8. Favorite color to wear
  9. Favorite lunch spot (when you were working in your most recent office)
  10. Favorite lunch spot currently
  11. Favorite quick service restaurant in NYC
  12. Favorite restaurant in NYC
  13. Favorite song in a genre you don’t normally like
  14. Have you ever broken a bone or gotten a scar? How’d it happen?
  15. How much wood COULD a woodchuck chuck if a woodchuck could chuck wood?
  16. If someone made a movie of your life, what genre would it be?
  17. If you could be a cartoon character for a week, who would you be?
  18. If you could go back in time and pay more attention to any class in high school, what would you choose?
  19. If you could have an actual spirit animal what would they be?
  20. If you could have any job in the org for a week, what would it be?
  21. If you could magically become fluent in any language, what would it be?
  22. If you could meet any historical figure, who would you choose and why?
  23. If you could meet any living person for dinner, who would you pick and why?
  24. If you could pick up a new skill in an instant what would it be?
  25. If you could shop for free at one store, which one would you choose?
  26. If you could start a charity, what would it be for?
  27. If you had a personal assistant, what would be the first thing you ask them to do?
  28. If you had to perform on a talent show, what would you do?
  29. If you had to teach a class, what class would it be?
  30. If you left your current life behind and ran away to follow your dreams, what would you be doing?
  31. If you were a wrestler what would be your entrance theme song?
  32. Name a brand you are loyal to
  33. Name a fun historical fact.
  34. Name a toy you enjoyed playing with as a kid.
  35. Name one thing that was on your bucket list that you’ve done
  36. What are you kind of snobby about?
  37. What band would you travel back in time to see?
  38. What book have you read lately (it’s been a while since the last time this was asked, maybe you’ve read a new thing since then?)
  39. What celebrities have you met?
  40. What class would you want to take?
  41. What country is on your bucket list to visit?
  42. What do you look forward to about getting older?
  43. What fictional family would you be a member of?
  44. What have you done your entire life but are still bad at
  45. What hobby would be a lot of fun to get into?
  46. What household chore do enjoy the most?
  47. What ice cream flavor do you like?
  48. What is the best fruit?
  49. What is the best piece of advice you’ve received?
  50. What is the most useless thing on your desk right now?
  51. What is the weirdest food combination you’ve made and tried?
  52. What is the worst fruit?
  53. What is your biggest pet peeve?
  54. What is your cellphone wallpaper?
  55. What is your favorite childhood vacation?
  56. What is your favorite family tradition?
  57. What is your favorite holiday and why?
  58. What is your favorite magical or mythological animal?
  59. What is your favorite or memorable childhood vacation?
  60. What is your favorite sport to watch? If you don’t like watching sports, take the question as broadly as possible.
  61. What movie have you seen lately (it’s been a while since the last time this was asked, maybe you’ve read a new thing since then?)
  62. What music do you put on when you want to get pumped?
  63. What song do you hate and have to turn off the radio when it comes on?
  64. What subjects should be taught in school but aren’t?
  65. What superpower would you want?
  66. What teacher did you have that you didn’t like? Why?
  67. What topic could you give a 20-minute presentation on without any preparation?
  68. What was a notable costume (maybe for Halloween) you had growing up or later?
  69. What was something you thought would be easy until you tried it?
  70. What was something you thought would be hard until you tried it?
  71. What was the first album/tape/cd/mp3 you bought?
  72. What was the name of the street you grew up on?
  73. What was the worst job you ever had?
  74. What was your favorite game to play when you were a kid?
  75. What was your worst haircut experience?
  76. What works of art have really made an impression on you?
  77. What would the title of your autobiography be?
  78. What would you change if you were CEO?
  79. What would you do if you were invisible for a day?
  80. What’s a book you enjoyed as a kid?
  81. What’s a movie you enjoyed as a kid?
  82. What’s a work (not necessarily here) achievement that you are proud of?
  83. What’s the first thing you do when you get home from a trip?
  84. What’s the most beautiful place you’ve ever been?
  85. What’s your “goto” joke?
  86. What’s your favorite Summer Olympics sport?
  87. What’s your favorite baked good?
  88. What’s your favorite cheese?
  89. What’s your favorite dessert?
  90. What’s your favorite smell?
  91. What’s your favorite sport to play (as usual for sporting questions, please interpret the term “sport” as broadly as you need in order to answer the question)
  92. What’s your go-to diner order?
  93. What’s your perfect sandwich?
  94. What’s the best or worst prank you’ve played on someone?
  95. What’s the most outdated piece of tech you still use regularly?
  96. What’s your drink of choice? (Either alcoholic or non.)
  97. When did you like the movie more than the book?
  98. When you’re having a bad day, what do you do to make yourself feel better?
  99. Where’s the most surreal area you been to?
  100. Where’s your favorite place to nap?
  101. Which celebrity chef would you like to fix you a meal?
  102. Who is one of your favorite (living) musicians?
  103. Who is your favorite athlete?
  104. Who was your favorite teacher?
  105. Who would play you in a movie of your life?
  106. You have a week to spend in a place you’ve never been before (travel not included), where do you go?
  107. You have to sing karaoke, what song do you pick?
  108. You have your own late night talk show, who do you invite as your first guest?

Updates:

  • Updated 8/18/2020 with 20 more questions!
  • Update 6/3/2021 I added more questions in a follow up post

I’ve been working on a project to create a Bluetooth “keyboard” with arcade buttons as the switches. Of course I want the buttons to light up. And I’d like to do this without using too many pins on my microcontroller. Naively if I had ten buttons (which I do) that would be 20 pins for the buttons and LED’s. The board I’m using has 21 pins. So that’s doable, but then doesn’t leave room for a lot of expansion (I also want a volume knob for instance…).

Button Matrix

matrix diagram

The solution I looked at was well documented around the web. I mostly used this sample from Adafruit since I was looking for examples using CircuitPython. I used a pair of Adafruit’s STEMMA wired buttonsto wire this up. The two rows of five colored buttons mimicked my real world project so it helped to visualize what I was doing. Each button has a 3 wire JST connection coming out of it with a white, black, and red wire. The white and black wires form a circuit when the button is pressed. For each board of five wires (my row), I connected all the black wires to the ground rail on a breadboard to wire them together (the rail wasn’t connected to ground). The other board was wired to the other power rail. For my columns, I just paired up each of the colors (the two blues, the two whites, etc). I plugged their corresponding white wires to a row on the breadboard. I believe that the red button is intended to be wired to a pull-up resistor which I didn’t need for this project. Just so they wouldn’t be in the way, I wired them up similar to the white wires.

Then to connect to the board, I plugged the two rows (the power rails) to pins 6 and 7 of my board. The columns were plugged into 9, 10, 11, 12, 13. I pulled sample code from the Adafruit site and tweaked it to my configuration (2 rows instead of 4, 5 columns instead of 3, pin numbers, etc). The adafruit_matrixkeypad library does most (all) of the heavy lifting here.

import time
import digitalio
import board
import adafruit_matrixkeypad

cols = [digitalio.DigitalInOut(x) for x in (board.D9, board.D10, board.D11, board.D12, board.D13)]
rows = [digitalio.DigitalInOut(x) for x in (board.D6, board.D7)]
keys = (("Blue 1", "White 1", "Yellow 1", "Black 1", "Red 1"),
        ("Blue 2", "White 2", "Yellow 2", "Black 2", "Red 2"))

keypad = adafruit_matrixkeypad.Matrix_Keypad(rows, cols, keys)

print ("Start pressing buttons")
while True:
    keys = keypad.pressed_keys
    if keys:
        print("Pressed: ", keys)

    time.sleep(0.1)

And it worked. Almost.

Whenever I pressed any button, it would show up as if the corresponding button on the next row was also pressed. After some hand wringing and checking all of my connections I realized that my breadboard actually has a short across those power rails. After pulling out all of the connections, rotating the board, and trying again, it worked just fine.

button matrix wired

IC the Lights

Next I needed to get the lights working. I knew you easily create this type of output using shift registers. And as it happens I have about a dozen of 74HC595’s kicking around in a drawer. Problem is, I had no clue how to use them. I got lucky with some articles I happened to stumbled upon that had an example. Page 98 (according to the PDF, it’s 111 if you’re using the numbers on the bottom of page) of the Experiments Guide for Metrohas an article about adding “More LED’s”. That’s a good start for the wiring up. Only two problems.

  1. The sample code is in C not CircuitPython
  2. I want 10 LED’s not 8

Instead of figuring things out from scratch, I did a little googling and came across nuke66’s project which was pretty much exactly what I needed. Again, all I had to do was change the pins to what I had. The sample pretty much just toggled everything on or off. Controlling all of the lights at the same time is pretty easy, so why not something more fun? Let’s create a binary timer. Count from 1 to 256 (2 raised to the 8th) using the LED’s as outputs. So I made (minimal) changes to code. Sadly, I didn’t think to take a video of this marvel of modern electronics.

import time
import digitalio
import board
import simpleio

data = digitalio.DigitalInOut(board.D2)
data.direction = digitalio.Direction.OUTPUT

latch = digitalio.DigitalInOut(board.D4)
latch.direction = digitalio.Direction.OUTPUT

clk = digitalio.DigitalInOut(board.D3)
clk.direction = digitalio.Direction.OUTPUT

data = 0
while True:

    data += 1
    if (data == 256):
       data = 0

    # write to 595 chip
    latch.value = False
    simpleio.shift_out(data, clk, data) 
    print("sending: {0:#010b} {0}".format(data),end="\n")
    latch.value = True
    time.sleep(0.1)

Next up: light them up based on which button is pressed. The button matrix already allows you to attach data to the button object which you get back when you query what’s been pressed. Instead of a meaningless label, why not just put in the id of the LED? Numbering each LED with a power of two will let me simply add up the keys pressed and send that out to shift register.

keys = ((1, 2, 4, 8, 16),
        (32, 64, 128, 256, 512))

# ...

while True
    keys = keypad.pressed_keys
    data = sum(keys)

    # ...
    simpleio.shift_out(data, clk, data) 

That works except for the last two buttons which are greater than the default 8 bit limit of simpleio.shift_out. How do I wire in those two LEDs? I could just wire in a second shift register with 3 more wires but that would be more wires than it would take to just wire in two more LED’s, make the code more complicated, and be really dumb.

The designers of the 595 agree with me. As it turns out, you can daisy chain multiple chips together. The bad news: I have no idea how to approach that. After some more google I found a bunch of videos that were helpful in that they showed what I wanted to do, but unhelpful in that it was a mess of wires and not clear what they were doing. OK, videos out. Guess I’ll have to read to get the answer here.

Mostly I was looking for a good diagram, which is what I found on protostack. Following this I saw that all I needed to do was:

  1. Connect pin 9 from the first shift register to pin 14 of the second one
  2. Connect pin 11 on both chips together
  3. Connect pin 12 on both chips together

I had started off on a half size breadboard so I needed to tear down everything I had to make room for the new chip and LED’s. In doing so I forgot to tie the OE (output enabled) to ground. This had some annoying and confusing results. Essentially the output would flicker because nothing was telling it whether to be on or off. The output would be more reliable if I held some of the wires (which really confused me). This reminded me of last time when I forgot to include a pull-up resistor in a button. I’d like to say that’s how I discovered the problem. But no, I went the classic route of taking it apart again and redoing all of the connections. I realized I didn’t have enough wires to connect the pins to ground and that’s what I had forgot.

Now that I had everything wired correctly, I still needed to figure out how to control the additional input. If I tried sending anything higher than 255 I was still not getting my new LED’s to light up. Reading through the CircuitPython doco, I saw that the shift_out function has a default paramter of bitcount set to

  1. Well… I want 16 bits. Setting that parameter worked.

Completed

Here are some pictures of the “completed” project

fully_wired.jpg

fully_wired_top.jpg

Frizting diagram

fritzing.png

All of the code can be found in the Day 12 pull request in my repo.

In my last go round I spent a lot of time mucking about with C++ to get things working. While searching through the Adafruit site, I came across a newer Bluetooth friendly device, this one capable of running CircuitPython. There’s even a tutorial for turning it into a Bluetooth keyboard. So I bought two. Due to Covid and the fact that Adafruit is focusing on producing PPE, it took an extra week or so to arrive. I got them this week and immediately started playing.

CircuitPython

CircuitPython is a version of Python that will run on a whole bunch of boards. Anything in the Adafruit line that is “Express” seems to be able to run it. Some Arduino boards support it as well.

Installation is pretty trivial on the Feather Express I got. The Adafruit site has a pretty thorough explanation. Pretty simply though, you plug it in to your computer. It will install itself and then automatically present itself as a file system.

Install
CircuitPython

When that happens, go to the CircuitPython download site, download the installation for your board, and then drop that into the new folder. The board will restart and now the root folder will have code.py. Write your python there. Whenever you save it will automatically reload and run that script.

Hello World

The Hello World app is pretty easy (in fact it’s what comes in code.py by default.

print("Hello World")

That’s it. This will just print “Hello World” to the serial bus. You see it by opening up the serial port and watching it. While you can use the Serial Monitor from the Arduino IDE, it’d be nice to no longer need that tool at all. Luckily, PuTTY can handle serial ports as well as SSH. First you need to figure out what port the device is connected to. If you have multiple devices they’ll all connect to a different port, even if they aren’t plugged in at the same time. Which is convenient since you can mentally associate a different port with each device. To determine which port it’s using open up the Device Manager and expand the Ports (COM & LPT) node. It will be listed there. In my case, it was port 12.

Looking up the COM port

Fire up PuTTY, select the serial radio button, and enter COM12 in the address bar. I left the speed at 9600 and it worked fine. Press connect and you’re now connected to the console output of your board. You may need to restart the program (just save it again).

PuTTY

I had some issues using vim, which was disappointing. Saving wouldn’t trigger a restart. I moved to Visual Studio Code. My preferred way to work is actually with both tools running, using VS Code for most editing tasks and switching to vim for specific types of edits. This actually works out pretty well. The only hiccup is that after saving in vim, I need to switch to VS Code and save it again if I want the code to run. It seems that the interpreter tries to evaluate the code before vim is done saving it.

Another nice touch is that any syntax or runtime errors automatically go to the serial output. For example, if you try to call a function that doesn’t exist, the board will stop evaluating and just dump the error out. Since you may not be looking at the serial output all the time, the board will flash it’s lights so you know there’s an error.

Back to the Box

Seeing as I already had a working set of buttons implemented in C++ on my button box, I wanted to try and rewrite that code in Python. It took me a couple of nights (and some frustration) to get it working in C++. On the other hand, it was about an hour or so to rewrite it all in Python. I had a couple of things going for me.

  1. I had better examples (including nearly exactly what I wanted) in CircuitPython
  2. I already compiled a list of all keystrokes I wanted to be able to perform
  3. Adafruit has put together a great set of libraries that makes the tasks I was looking to perform really easy

In addition to that, the feedback loop is super fast in CircuitPython. Write code. Save. Debug. Repeat. No compiling, no lengthy deploy process since it’s just a small script.

So not only was I able to bang out the code to get me back to where I was pretty easily, I was able to add the code to turn the rotary encoder (spinning knob) that was already on the box into a volume knob.

Today’s pull request has a bunch of files in it, but mostly because I checked in the python dependencies I need in order to get. I also included a couple of scripts that I wrote to just test specific things in isolation (like buttons or the rotary encoder).

Hardware

The hardware side was a little trickier. First, these boards don’t come with the headers attached. So I had to solder them myself. This is normally a scary point for me, but because of another project I had been working on, I was a little more confident going in. In fact I took this as an opportunity to solder a bunch of headers on a variety of boards I had lying around. This went pretty well (no shorts!) and didn’t take too long. I made some mistakes, but was able to fix them all.

This is what the board looked like when I was done. The blue sticker is there to differentiate it from other types of boards (which have another color sticker) and my other board of the same type (which has a different number written on it)

Soldered Feather

And here’s a close up of the soldering work.

Close Up of Solder Work

My next problem was that the buttons seemed to be firing presses pretty sporadically. After about half an hour of frustrated debugging, I realized that the sample code I was using wasn’t explicitly setting the buttons to use a pull-up resistor. Adding the line button_top_red.pull = Pull.UP for each button fixed that! There was another way to handle this, plugging a third wire from the button to the 3.3v pin on the board. The STEMMA buttons I have for breadboarding do have a third wire, and I was able to confirm that plugging it into power would fix the issue. The reason I prefer the pull-up resistor solution was because I have no idea where I’d attach a third wire to the buttons I have. This is a hole in my understanding how buttons work. I’m fine with it for now, but will need to figure this out at some point.

At this point, I was at parity with what I had before but I really wanted a volume knob. I found that I would absentmindedly spin the knob on the box even though I knew it didn’t do anything. I really wanted it to work. The code was easy, and it was easy to test with my breadboard friendly rotary encoder that I had. But the one I had in my box didn’t have the easy to attach to header pins. So I grabbed a piece of protoboard, cut it down to size a bit, and soldered the encoder to it along with some wires.

My Solder Job

This is what it looks like from the top (and plugged into a breadboard for testing)

Rotary Encoder

Conclusion

It was a really busy day, but much more productive than I have been in the past. Between the speed of developing with CircuitPython and confidence built up with the electronics aspects, I was able to take on more than I normally would and be confident that I would finish everything.

With all of the Zoom meetings and working from home, I decided to tackle the task of configuring my buttons project to be able to control Zoom. The big things I wanted were:

  1. Start a new Zoom meeting
  2. Mute/unmute
  3. Enable/disable video
  4. Close my Zoom meeting (I hate fumbling with the UI and clicking multiple buttons on the screen to get out of a meeting)
  5. Share screen

Zoom has a list of shortcuts on their site. Most of what I want are easy key combos. For example, starting a meeting is command + control + v. Some of them were a bit more complicated though. Closing a Zoom meeting or sharing a screen both have shortcuts, but the shortcuts bring up a dialog box. Having to click more buttons on my keyboard or with mouse defeats the purpose of dedicated hardware buttons. Luckily, both of those situations have pretty standard flows. Closing a Zoom maps to command + w followed by enter. Sharing maps to command + shift + s then right arrow and then finally enter.

Refactor

Basically I need to be able to support chords. This will take a refactor. As it stood, the code just had a giant switch block (really lots of if’s) that figured out which key set to send. Now I need to be able to send multiple keys per button press. It’s high time I create a command class. For lack of a better name, I’ll call it QuinCommand. It can take up to five different key combinations that it will play out in order. (get it? “quin”… okay so it’s my name too. It works on multiple levels.) It will need to be able to send out Bluetooth commands, so we’ll need to abstract that out to a dedicated class too. Sticking with my theme of picking bad names, that’ll be called Blue. This cleans up a lot of my main file. All that that’s left is to pull out all of the constants that define the specific key combos and comments that describe them and where to get more info on creating more. That was a lot of code that gets moved to CommandsConstants (probably the best name of the bunch…).

With all of this cleanup done a couple of things stood out at me. First, there’s still a lot of boilerplate code that I’m no longer using. Delete it. Second, there’s a whole sub-folder of code kicking around that was copy and pasted of this project. It confuses me whenever I open up the project. Delete that too.

Much better.

Relearning C++

It’s been ~20 years since I’ve seriously written any C++. And that was high school. So this entire refactor took a lot of googling. How to make classes, how to define a header file in such a way that you can include it multiple times. How to handle arrays or strings. That last bit kicked my ass quite a bit. I’d like to say I researched and figured out the right way to do things. But no, I just stack overflowed (the site) for a bit tried a bunch of things until something worked. I’m 💯 percent sure that it’s not the best answer. I’m trying to send constant length constant strings around, there has to be a way to do that without resorting to a memcpy. At the end of the day (and it really was the end of the day when I was working on this – I was tired) I went with a cludge that worked.

Wrapping up

I’d like to change the commanding architecture to be based off of an interface (or an abstract class with all virtual methods… cuz C++) and have completely custom logic for what happens when each command is invoked. It’d also be nice to wrap the command in a button class that tracks the state of the button press and handles whether or not to resend a command if I haven’t taken my finger off the button yet. Realistically, that’s probably not going to happen for a long while. The box works well enough for now and I have a couple of new boards on order that run python. So it’s likely that I’ll be porting this over to that, which should have a faster development feedback loop for me.

Writing all of this C++ really made me miss the simplicity of C#.

Here’s the code for this post.

I’ve finally taken the time to configure Windows Terminal. I’ve been a big fan of ConEmu in the past. It has tons of configurable settings and features. But honestly, I switched to it for the easier copy/pasting in the command line. Since the new Windows Terminal can do that, then I thought it would be worth giving a shot.

Below is my current configuration after about an hour of reading docs and fiddling. I like that I was easily able to find the Desert theme (which is what I’ve been using for vim for over a decade now).

{
    "$schema": "https://aka.ms/terminal-profiles-schema",

    "defaultProfile": "{0caa0dad-35be-5f56-a8ff-afceeeaa6101}",
    "useAcrylic": "true",

    "copyOnSelect": false,
    "copyFormatting": false,

    "profiles":
    {
        "defaults":
        {
            // Put settings here that you want to apply to all profiles.
        },
        "list":
        [
            {
                // Make changes here to the cmd.exe profile.
                "guid": "{0caa0dad-35be-5f56-a8ff-afceeeaa6101}",
                "name": "Josh Command Prompt",
                "commandline": "cmd.exe /k %HOMEPATH%\\OneDrive\\bin\\cmdinit.bat -new_console",
                "colorScheme": "Desert",
                "hidden": false
            }
        ]
    },

    "schemes": [
        {
            "name": "Desert",
            "black": "#4d4d4d",
            "red": "#ff2b2b",
            "green": "#98fb98",
            "yellow": "#f0e68c",
            "blue": "#cd853f",
            "purple": "#ffdead",
            "cyan": "#ffa0a0",
            "white": "#f5deb3",
            "brightBlack": "#555555",
            "brightRed": "#ff5555",
            "brightGreen": "#55ff55",
            "brightYellow": "#ffff55",
            "brightBlue": "#87ceff",
            "brightPurple": "#ff55ff",
            "brightCyan": "#ffd700",
            "brightWhite": "#ffffff",
            "background": "#333333",
            "foreground": "#ffffff"
        } 
    ],

    "keybindings":
    [
        { "command": "duplicateTab", "keys": ["ctrl+t"] },
        { "command": "closePane", "keys": ["ctrl+w"] },
        
        { "command": {"action": "copy", "singleLine": false }, "keys": "ctrl+c" },
        { "command": "paste", "keys": "ctrl+v" },

        // Press Ctrl+Shift+F to open the search box
        { "command": "find", "keys": "ctrl+shift+f" },

        // Press Alt+Shift+D to open a new pane.
        { "command": { "action": "splitPane", "split": "auto", "splitMode": "duplicate" }, "keys": "alt+shift+d" }
    ]
}

Interesting tidbits I stumbled across while reading the docs

  • Holding alt while opening the settings will open the default settings
  • Pressing any arrow key while holding alt will jump to the pane in that direction.
  • Pressing any arrow key while holding alt-shift will resize current the pane in that direction
  • Settings are reloaded as soon as you save the settings file. No need to reload tabs. This confused me while I was trying out different color schemes
  • Chrome-style shortcuts work for zooming in/out in a pane
  • Aero doesn’t work on my Surface3 🙀

Wishlist

It would be nice to be able to click on links in the console and have them open in my browse. There’s an issue open for that, so hopefully it makes it into an upcoming version.

Another ConEmu feature that I would love to see is the ability to open up a tab as an administrator The current workaround is to Ctrl+Shift+click on the icon in the taskbar to open a dedicated admin prompt. This is a bit more work than I’m used to, but most of what I’m adminning about for is to just run Chocolatey. I can make due.

Arduino, How-To comments edit

It’s been a while since I’ve worked on my Arduino project to create a Bluetooth keyboard. In that time I have been using my keyboard a little bit, but it needs some work, ranging from small tweaks to major overhauls. This post is to remind me how to do the small tweaks. Some of it will be very specific to my current setup.

The first thing I’m remembering, and this sounds really dumb but I had to relearn it, was that the Arduino needs to be on. I had assumed that merely plugging it into my laptop would have been enough, but nope. Fully powered on. Check. ✔

Now that the board is on, we can verify all of the settings in Arduino IDE, including making sure the correct board is selected and the correct com port is being used. For my setup Adafruit Feather 32u4 and COM3 are the expected values.

Select Board

Select Board

Select COM Port

Select COM Port

Now that the board is connected, to view debug output while it’s running you can open up the Serial Monitor with Ctrl-Shift-M.

My board has an guid of d7:63:b2:85:c4:24

Evolution

Today I was able to complete the first fully working prototype of my keyboard. It has 6 16mm arcade buttons – two each of green, yellow, and red – runs on a 350mAh lithium ion battery, and is completly wireless. It doesn’t even have a wire to charge it since I didn’t have enough space to mount the port in the case.

Build It

Mostly today was a build day. I had most of the code in place, so all that was left was to assemble everything. First I made a template on paper to figure out the placement of the buttons. I wanted to make sure that the arcade buttons were placed far enough apart so that I could fit the power button on the side. After a lot of measuring and some fiddling I settled on the below layout.

Step 1: Create a template

To be sure the spacing worked, I placed the buttons directly on the paper. This was the third layout I tried. Also, I originally planned on blue, green, and red buttons. After seeing them lined up, the blue and the green were too similar in color, so I swapped in the yellow buttons for some contrast.

Step 2: Check the layout

To be absolutely certain, I created a quick mock up a cardboard box. The layout was just right.

Step 3: Check the placement

To transfer the layout to the case, I taped the pattern to the top and drilled 1/16th holes in the center.

Step 4: Place the template

Forstner bits were used to drill out the 16mm holes for the buttons. It took me a little bit to get the hang of drilling the holes. Sometimes the drill caught on the plastic and scratched the surface of the case.

Step 5: Drill holes

The wires took up more space than I expected. It would have been helpful to daisy chain all of the grounds across a common wire, removing half of the wires needed. Also, the rest of the wires could have been cut much shorter or routed around the edge of the enclosuer, taking up less room.

All of the wires terminate in a breakout FeatherWing.

Step 6: Wiring

The fit was tight enough that I didn’t need to mount the feather to the case. The wires held it in place with little to no movement when the bottom was screwed on.

Front View

You can see the power button on the side.

Side View

Code

With everything assembled it was time to test it out. And it didn’t work. After a little trial and error, I realized that the keyboard would only work if my laptop was plugged into it via USB and I had the Arduino serial monitor plugged in. Looking over my code a bit, I see that I still had a line of code at the very beginning telling the board not to start up unless it detected a serial console. Removing that fixed the first problem.

Next, whenever I pressed the volume down or up buttons for a brief moment, the volume would go all the way to 0 or 100. No in between. It registered as way too many key presses. Adding a small delay at the end of the loop solved this problem.

Here’s the useful command I used to create the thumbnails for this post: magick mogrify -resize 33% -path ./thumbnails *.jpg.

Feather

Today’s progress is a bit misplaced in the “Pi Project” folder. I wound up using my Adafruit Feather 32u4 Bluefruit LE to emulate a keyboard. Since this is exactly what it was designed to do, it really wasn’t that hard. Which means it took me a long time. My goal was to use a Bluefruit LE UART Friend connected to my Raspberry Pi. That was beyond my current skills so I decided to take smaller steps. The Feather has lots of samples doing exactly what I want to do, so I went that route.

The plan is still to go back to the Pi though since my end goal is to make a keyboard that gets updates from the computer it’s connected to and I assume it’d be easiest to do that with a restful API. But that’s for Future Josh to work through.

Working with several tutorials and code samples I was able to create a simple app that sends custom strings of keyboard codes to whatever device is paired.

Code

Below are the highlights of the application. First it declares the commands to send as constants, and then polls for button state and sends corresponding messages.

BLE Commands

Two types of BLE commands are supported, keyboard codes, and control commands. Keyboard codes are sequences of key downs (key ups are inferred by sending either the next code, or by sending a message with no codes). Keyboard codes are sent in a message that is up to 8 bytes long.

  • The first byte is a bit mask of any modifiers (shift, alt, etc)
  • The second byte is always 00
  • Bytes 3 through 8 are the keys to send

For example 08-00-07 is the command for pressing the Windows Key + D. 08 is the left Windows key, and 07 is the letter D (it’s case insensitive, if you want to have an upper case D, then also send shift).

As stated above, up to 6 keys can be sent at once. So to send abc, that would be 00-00-04-05-06. But then this would continue to send c repeatedly since we never sent the key up signal. To do that, just send an empty message with 00-00.

A complete listing of the keys can be found in section 12 here.

The other type of message that I’m sending is a control command. This is used to emulate media buttons like play, stop, and volume control. In my example I use it just for play (which will also pause). Adafruit’s sample code has a listing of some available commands.

Code Logic

Each loop of the main method polls the state of the buttons to determine which messages to send. It also records its state so the next iteration can either send the key up signal in the case of the keyboard codes, or to simply not resend the play command a second time (thereby pausing the music if the button is held down for more than a fraction of a second).

It’s all pretty hard coded now, but the idea is to have it evolve to be more configurable over time.

char CMD_MISSION_CONTROL[] = "01-00-52"; // (Left) Control + Arrow Up
char CMD_APP_WINDOWS[]     = "01-00-51"; // (Left) Control + Arrow Down
char CMD_SHOW_DESKTOP[]    = "08-00-07"; // (Left) Window + D
char CMD_VOLUME_UP[]       = "00-00-80"; // Volume Up
char CMD_VOLUME_DOWN[]     = "00-00-81"; // Volume Down
char CMD_VOLUME_MUTE[]     = "00-00-7F"; // Volume Mute
char CMD_F14[]             = "00-00-69"; // F14
char CMD_KEYS_UP[]         = "00-00";    // No keys held

void loop(void)
{
  int pressed = 0;
  int playPressed = false;
  if ( digitalRead(5) == LOW )
  {
    pressed++;
    printKeyboardCode(CMD_MISSION_CONTROL);
  }
  if ( digitalRead(6) == LOW )
  {
    pressed++;
    printKeyboardCode(CMD_APP_WINDOWS);
  }
  if ( digitalRead(9) == LOW )
  {
    pressed++;
    printKeyboardCode(CMD_SHOW_DESKTOP);
  }
  if ( digitalRead(10) == LOW )
  {
    playPressed = true;
    if (!playButtonPressedLastTime)
    {
      printControlKey("PLAY");
    }
  }
  if ( digitalRead(11) == LOW )
  {
    pressed++;
    printKeyboardCode(CMD_VOLUME_UP);
  }
  if ( digitalRead(12) == LOW )
  {
    pressed++;
    printKeyboardCode(CMD_VOLUME_DOWN);
  }

   if (pressed < 1 && buttonsPressedLastTime > 0){
    // send the key-up command
    printKeyboardCode(CMD_KEYS_UP);
  }

   buttonsPressedLastTime = pressed;
  playButtonPressedLastTime = playPressed;
}

 void printKeyboardCode(char keys[])
{
    ble.print("AT+BleKeyboardCode=");
    ble.println(keys);
}

 void printControlKey(char keys[])
{
    ble.print("AT+BleHidControlKey=");
    ble.println(keys);
}

Wiring

Close Up

Wiring is pretty simple for this device since it’s essentially made for this use case. I strung together 5 buttons with a common ground, and plugged each of the buttons into the pins 5, 6, 9, 10, 11, and 12. I have a Battery on order, and will wire up that and a power switch once they arrive.


I followed a mix of instructions, including Adafruit, and ElectronicWings to start playing with talking to and from my Raspberry Pi over a serial connection from my Windows Surface. I used a TTL cable from Adafruit.

Following are instructions for setting up communication between a Raspberry Pi 3 (not a zero) and a Windows laptop.

Setting up the Pi

First thing to do on the Pi is to turn of shell login via serial port.

  1. sudo raspi-config
  2. Select “Interfacing Options”
  3. Select “Serial”
  4. When asked “Would you like a login shell to be accessible over serial?” select no
  5. When asked “Would you like the serial port hardware to be enabled?” select yes
  6. Reboot the device

Next is to connect the cable to my Pi. My Pi was powered by USB already, so I didn’t connect the red (5v) wire to the Pi. Just hook up the wires up as follows, (or see the picture below).

  • Black -> Ground
  • White -> TXD
  • Green -> RXD

Wiring the Pi

Setting up the Windows Laptop

First step is to install the drivers on my laptop for the cable. I had the older version of the cable, so I needed the Prolific Drivers. There’s also a link to this from the Adafruit tutorial.

Now once the the USB cable is plugged into the laptop it will show up as a new COM port. To figure out which one it is either find it in the Device Manager or use the mode command.

Device Manager

>mode

Status for device COM5:
-----------------------
    Baud:            9600
    Parity:          None
    Data Bits:       8
    Stop Bits:       1
    Timeout:         OFF
    XON/XOFF:        ON
    CTS handshaking: OFF
    DSR handshaking: OFF
    DSR sensitivity: OFF
    DTR circuit:     ON
    RTS circuit:     ON


Status for device CON:
----------------------
    Lines:          32766
    Columns:        112
    Keyboard rate:  31
    Keyboard delay: 1
    Code page:      437

Notice that the mode command will also conveniently print out the baud rate (you’ll need this in the next step). This information is also available from device manager too by going in to the port’s properties.

Open up the serial port in PuTTY, using the COM5 port found above.

PuTTY

Connecting

Back on the Pi find the correct serial port. As I understand it (which is 90% likely to be wrong), on the Raspberry Pi 3, the UART port is going to be ttyS0 and the Bluetooth port (also serial) will be ttyAMA0. ls -l /dev will give you information about the ports.

$ ls -l /dev/serial*
lrwxrwxrwx 1 root root 5 Jun 22 15:12 /dev/serial0 -> ttyS0
lrwxrwxrwx 1 root root 7 Jun 22 15:12 /dev/serial1 -> ttyAMA0

From here echoing out a string in the Pi to /dev/serial0 will have it show up in PuTTY.

$ echo "hello world" > /dev/serial0

PuTTY