This post is part of a series about building electro-mechnical PIN-cracking robots, R2B2 and C3BO.
This is a proof of concept for @JustinEngler's C3BO (https://github.com/justinengler/C3BO) using transistor controlled relays. It was prototyped by modifying Blink from the Arduino sample project.
The schematic was obtained from Timbermanbot (https://github.com/vheun/ArduinoPlays...) as seen on Hackaday (http://hackaday.com/2014/07/26/pwning...).
In the video, You'll notice I've replaced the touchpad for your finger with a wire to the headphone jack's ground as the circuit ground. The two pieces of copper tape were no longer sticky enough to stay by themselves, so I am holding them down. They press two and 5 with about 8 key presses per second.