The LED chaser contains an ATtiny85, which controls two SN74H595N shift registers. These shift registers power 16 individual LEDs, which are current-limited by 470Ω resistors.

A 100nF capacitor is used for decoupling power to the ATtiny85.

A pause switch triggers the reset functionality of the shift registers and the ATtiny85 microcontroller, halting the execution until the switch is turned back on. When the switch is off, a 10KΩ resistor pulls these pins to ground.

Two CR2032 batteries are used in parallel to provide 3V to the circuit, and double the amp-hours of one coin-cell battery. The circuit can, however, operate with only one coin-cell battery.

Sockets are used to provide hot-swappable functionality and enable easy reprogramming of the ATtiny85 on the fly.