Adafruit’s Gemma, a very nice platform a little over an inch in diameter, is ideal for small and wearable projects. The device is inexpensive and based on the ATTINY85 microcontroller. Adafruit has, once again, done an excellent job of designing a cool tool for the electronics hobbyist.
Small as this is, I found myself wanting to shrink the electronics footprint of a wearable circuit even more. I didn’t have a need for some of the Gemma extras such as USB connector or JST for LiPo battery. So, I decided to experiment a little to get a wearable circuit to the bare essentials.
I already had in my toolkit the Adafruit USBtinyISP programmer, and the Evil Mad Scientist ‘2313 Target Board with ZIF socket. This board has a simple jumper modification to allow it to be used with ATTINY45/85.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.