GEMMA and Trinket are great when you want a tiny, low cost microcontroller to embed in your projects. One of the tradeoffs, however, is that they can’t send data back to the computer for debugging sensor values.
For instance, you want to make a pair of Firewalker sneakers with Gemma instead of Flora, but there’s no easy way to calibrate your Velostat step sensor since you can’t see the numerical value of the reading. I recommend keeping a FLORA around for this purpose, even if you port to GEMMA later.
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, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, 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.