Bob Alexander built Blueprintf, a handheld serial monitor with data displayed on a cell phone.
I built a handheld serial monitor to use with my microcontroller-based projects, allowing me to debug them or send them commands from my cell phone or tablet. I can connect it to my project’s UART with two or three wires, then connect via Bluetooth to my cell phone, set the baud rate or auto-detect the rate, and then have one or two-way communication between the phone and the microcontroller. You can see my write-up at http://www.galacticstudios.org/blueprintf/. I’ve also posted the code, schematic, and PCB layout files.
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.