Circuit Playground Adafruit Circuit Playground Classic is an all-in-one board with built-in sensors and LEDs for practicing programming on real hardware. The Circuit Playground Classic is round and has alligator clip-pads so no soldering or sewing is required. The Circuit Playground Classic features an ATmega32u4 processor like the Flora. The board is powered by USB, a 'AAA' battery pack, or a Li-poly battery.