As part of my Big Trak refurbishment (not going as well as I wanted it to), I decided to use theAdafruit Prototyping Pi Plate to mount the additional electronics on.. The keypad was originally going to be the Big Traks own keypad, but I substituted one I’d made earlier (some 25 years ago!) – it’s a simple 4×4 matrix and you can see 4 resistors on the protoboard. There is a 5th next to them which acts as a limiter for the LED that’s on one of the switches.
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.