This activity works best with groups of 3 or 4.

Each group should get the following:

• Adafruit Circuit Playground Express (CPX) board https://www.adafruit.com/product/3333 (other microcontrollers could be used as well but other components will be needed. See below.)
• computer running Windows, OS X, or Linux (not tested with Chromebooks)
• spreadsheet program (the given instructions were tested with Google Sheets https://sheets.google.com/)
• Arduino Programming IDE https://www.arduino.cc/en/Main/Software
• microUSB cable (included with Circuit Playground Express)
• If using a different microcontroller, here are the additional parts needed
• multiple (3 or 4) LEDs of various colors
• set of three or four 200 – 400 ohm resistors for use with LEDs
• light sensor (photocell)
• 10k-ohm resistor for use with the photocell
• breadboards for building the circuit