Build your own physical computing blocks for the Raspberry Pi

Do you want to make physical computing with the Raspberry Pi easier? Then follow this instruction and build your own wooden physical computing blocks, which can easily be connected to the Pi with alligator clips instead of those flimsy jumper cables. 

This project is mostly a replica of the physical computing blocks that were used by the Raspberry Pi Foundation at the Maker Fare 2017 in New York. They were made by the awesome maker Ben Light – here`s a nice video that shows how he made them:

Because I haven`t found a tutorial, that shows exactly how to build them, I decided to make my own version of the physical computing blocks and share it with you.

What you need (for 1 station with 2 button blocks and 1 LED block):

• wooden board (7mm thick)
• some wood glue
• 1 Raspberry Pi
• 2 arcade buttons
• 1 big LED
• 1 resistor (68 Ohm)
• some wires
• 2 female-female jumper-cables
• 9 short screws (15 mm long)
• 1 longer screw (30 mm long)
• 10 fitting screw-nuts and washers
• 6 screws and spacers (e. g. from a SenseHAT)
• 4 female spade connectors
• 6 alligator clips
• soldering iron
• Dremel
• shrinking tubes
• needle nose pliers
• labeling machine

For my Pi-workshops with kids, teachers and students, I want the physical computing-part to be as easy as possible. So when I got a bunch full of old Raspberry Pi 1 boards with 4 GB SD-Cards, I teamed up with my dad, who loves to work with wood and has all the tools necessary for this project. Together, we made our own version of the physical computing blocks, and here’s how:

First we took a wooden board (7 mm thick) and cut it into pieces: one 150x105mm board for the Pi, six 5x5cm and six 5×5,5cm boards for the 2 button-blocks and the LED-block. Then we glued the smaller boards together in order to get 3 blocks, that look like this:

The next step is to drill a hole in two of the blocks top so you can fit in two arcade buttons. They`re usually 28mm wide. For the LED-blocks, you just need two small holes on the top. I used a Dremel for this task (and all other holes I had to drill). You also need two additional small holes on the other side of each block, where you put in the screws.

Now let`s have a look at the electronics: Shorten the two ends of the resistor a bit and solder one of them to the long leg of the LED (this is the positive pole). Take a short cable, remove the insulation, solder one end on the resistor and wrap the other end around the screw.

Then solder another cable to the short leg of the LED, strip the insulation off and wrap it around the other screw. Now put the washers on top and tighten the cables with the screw-nuts. If you want to, you can use shrinking tubes to cover up the soldering joints. 

Now let`s get to the buttons: Remove the insulation from another cable, put it in the female spade connector and use a needle nose pliers to tighten it up. Then do the same as before: strip the insulation, wrap the cable around the screw and tighten it with the washer and the screw-nut.

In order to mount the Raspberry Pi on the wooden board, you need to drill two holes (or four, if you use a newer model with 4 mounting holes). Then use the spacers from a SenseHAT (or any other spacer you have lying around) and screw the Pi to the board.

Because the old Raspberry Pi has only two mounting holes, I screwed another pair of spacers to the wooden board to prevent the Pi from bending. You also have to drill another 4 holes and put in the 3 short screws and the one long screw.

Then cut the jumper wires in half, strip the insulation off and connect them to GPIO-Port 2,3,4 and a Ground-connector. Wrap the other end of the cables around the screws (the longer screw is for the Ground-cable). Again, you can use shrinking tubes to give it a cleaner look. Now you can use a labeling-machine to mark the screws and ports on the Pi.

Software

Thanks to the downward-compatibility of Raspbian, you can always run the latest and greatest release of Raspbian on every Pi, even the first model. But this is not always the best solution. For example there was a time, where you could choose to boot Raspbian directly to Scratch in fullscreen mode. This is a perfect option for this project, because it`s made especially for younger children who don’t want to mess with the desktop UI. As a bonus, the older versions of Raspbian boot a bit faster on older Pis.

Because the GPIO-functionality wasn`t installed by default back then, I had to install it manually and deinstall some programs in order to fit everything on a 4GB SD-Card. If you want to download the whole image, just click here.

Now you can start programming with Scratch. Why not begin with a little game? Take a look at the „Astronaut Reaction Game“ and modify it in order to use the LED as the start signal and turn it into a two-player game, that’s controlled with the two buttons. Read this to learn how to control the GPIO-Pins with Scratch. The result could look like this:

I hope this tutorial can help you building your own physical computing blocks for the Raspberry Pi. If you encounter any problems, take a look at the schematic and/or the pictures. If that doesn`t help, write a comment and I`ll help you. Or maybe you also have some more ideas for other blocks besides the button and the LED. I`d love to see your ideas!