Another day, another EE that refuses to play Guitar Hero properly. [Julian Bleecker] went into the design of this Guitar Hero actuator not really knowing how to size solenoids properly. Luckily, trial and error can get you a long way. The first solenoids he purchased couldn’t apply enough force. The second was overkill. It was certainly strong enough but too heavy and too large to mount to the neck. The final set ended up being both the right size and working well even at 12V, half the design voltage. The elegant mounting system is what really makes this project shine. [Julian] provides the schematic for the ATmega168 driver board, which is an Arduino stripped of the extraneous bits.