Quantity   Component name
1 × ATTiny25/45/85 8 pin AVR microcontroller
1 × LTL2T3YR6JS - 5mm LED, yellow, 1150mcd, 60° viewing angle Just because I like yellow LEDs. Red ones work nicely too.
1 × CR2032 Batteries and Battery Accessories / Batteries
1 × Battery holder for CR2032
1 × PCB