Fidget spinners are fun little toys that spin around on a bearing and make surprisingly addictive stress relievers. With a flick of your finger you can set a spinner into a rapid spin and watch as it slowly comes to a stop from the forces of friction. You can even make spinning a competition with friends--see who can flick their spinner the hardest to get it spinning the fastest! But wouldn't it be cool to measure how fast a spinner is spinning? It turns out with an Adafruit Circuit Playground board you can build a simple tachometer that measures the speed of a spinning fidget spinner!
This project will show you how to use a Circuit Playground Classic or Circuit Playground Express board to build a fidget spinner tachometer that measures the speed of a spinner. Circuit Playground is Adafruit's all-in-one electronics learning board that has all the necessary components for this project, specifically a light sensor, NeoPixel LEDs, and the brains of an Arduino, built in to it so you can get started immediately with no soldering or other hardware setup. Even better you can build this project using either Arduino or CircuitPython code. If you're new to Python this is a good example of how a project can be converted from Arduino to Python code.
Before you get started you'll want to read the Adafruit Circuit Playground guide to learn more about the board.
Also you might find the Circuit Playground digital fidget spinner another fun spinner project to build with Circuit Playground. The digital fidget spinner uses the accelerometer built in to Circuit Playground to make a virtual fidget spinner that animates LEDs from the flick of your finger.