Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:1561431.

I wanted to create a 3D printed circuit using conductive ink similar to a Voxel 8 3D printer but on the cheap. I found some conductive glue at Radio Shack and used it to make a 3D Printed Train Crossing Circuit powered by an Arduino. The circuit just flashes LEDs back and forth like a train crossing and a key part of the circuitry is conductive ink placed in channels in a custom 3D print.

You can see more details at my YouTube Channel: https://youtu.be/k-52WRqUocw

I used this conductive glue from Radio Shack: http://shack.net/1R1aNR6