In the interest of not waiting too long after I build something to share it here, I’m going to drop a bunch of random info into this post, knowing that it may not be well written or cohesive, but I’ve decided that’s okay…
We built a physical version of the Logo Programming Language. If you’re not familiar with Logo, start at the Wikipedia page for Logo. If you are familiar and want to play, here’s an online Logo Interpreter you can have fun with.
Logo is an educational programming language known for its use of turtle graphics. Commands for movement produce drawings on a screen that teach students to understand, predict and think about the turtle’s motion by imagining what they would do if they were the turtle.
And finally, if you’re not familiar with Brinn Labs (where this was created) we
are the exhibit development group of a children’s museum, and we make safe, durable, fun, educational exhibits for museums and other institutions, mostly aimed at early learners.
Here’s the original concept I shared with the team. Things always change during the development process, but this is still pretty close to what we came up with.
In designing the physical board and pieces, I took inspiration from the block interface used by Scratch. In Scratch pieces fit together to help you figure out where things go, and color also help denote function.
Here’s a mock-up of the board where the pieces will go. The board has pockets that the pieces fit into, and in each pocket is a sensor that reads the back of the piece. Note that the pieces only fit into the pocket that matches the function. You can’t put a direction piece into the color pocket. The pieces also cannot fit in backwards or be rotated in the wrong direction. Designing this to work took some time, and it’s all there to help you get it right.
The right side shows the indent for the loop code, as well as the use of parens that many programming languages use. Note that the loop pieces are not required, but if you put in the beginning loop statement and not the end loop statement (or vice versa) you’ll get an error.
We’re using the QTR-8RC Reflectance Sensor Array boards from Pololu. Each pocket has one sensor board to read the barcode on the back of the pieces. The barcode allows us to use a binary code for each piece. This means no technology is embedded into the pieces, and they’re (fairly) cheap and easy to replace as needed.
Here’s a look at the print file for some of the pieces, showing the back. You can also (faintly) see the cut lines for the pieces.
Here’s a portion of the binary code for some of the pieces. We actually doubled it up as a sort of checksum to make sure things were read right.
Each sensor is mounted from the back of the panel with a 3D printed mount that sets it right below the surface. We found a gray filament that was a pretty close match to the gray HDPE we used for the front panel. The top part of the sensor mount matches the holes milled into the HDPE by the CNC router, and includes the radius of a 1/4″ router bit.
My favorite part about 3D printing the sensor mounts is that you can set the height of the part where the screws go to match the screws you use and the material you are screwing into so they go in the exact distance you want, and not too far. No screws poking through material, and no screws not inserted enough to get a good hold.
We couldn’t leave the sensors exposed, so we laser cut clear acrylic pieces to place into the pockets. Hopefully they’ll stand up to the abuse they’ll get, but if they get too scratched or worn, it’s easy to swap in a new one. (If you’re keep track, we’ve used a 3D printer, laser cutter, and CNC machine so far…)
Here’s a look at a mock-up of the pieces. This is an early iteration but shows some of the color choices as well as all the pieces together.
I’m not showing you the inside of the cabinet, but all of the sensors connect to a microcontroller that is connected to a computer. The microcontroller reads the sensors, determines which pieces are in which pockets, and reads the button presses to run the code on the computer and reset things.
To program the turtle, you put the pieces in the tray, and press “Run”. If you get an error it will show on screen and also blink an LED on the board for the “line” where the error is. Once you correct your error(s) you can hit “Run” again and watch your code execute. You can run over and over until you want to clear the screen by pressing the “Reset” button, which clears things and sends the turtle back home.
We didn’t implement pen up/pen down, because this is a simplified version meant for young children/early learners. I think that as far as a STEM component it turned out well, and creating it allowed me to combine my love of computers, programming, turtles, Logo, and design into something awesome.
I hope Seymour Papert would be proud of this. If you’re not familiar with his work, he’s been considered the world’s foremost expert on how technology can provide new ways to learn and teach mathematics, thinking in general, and other subjects.
People laughed at Seymour Papert in the 1960s, more than half a century ago, when he vividly talked about children using computers as instruments for learning and for enhancing creativity, innovation, and “concretizing” computational thinking.
Here’s some kids having a good time learning about coding!