Enter this light bulb replacement project. His brake light needed a new bulb, and he managed to make this 12V LED bulb work in the 6V socket. An LED is a really great choice for this application ...

I damaged the first bulb I cracked open by drilling ... the ground side of the ATtiny13. The ‘GND (12V rail)’ connects to the low side of the LEDs but that is separated from the ...