/challenges-projects/design-challenges/hats-off/b/blog/posts/spy-hat-progress-2Details required if you want to build your own Spy Hat! Parts list: Gemma, battery, HC-SR04 (or similar) ultrasound sensor, NeoPixel And the code:/* Spy Hat code AdaFruit Gemma Hats Off Challenge Oct 30, 2014 This code...en-USTelligent Community 12