Ready for a in depth project?
The engine runs at a high rate of speed, but gets to hot for PLA after 2-5 min. Id like to see someone make this made in ABS or a better power/solenoid setup for better heat tolerances.
to make this engine you must know how to use and program an Arduino. u must know the basics of electronics.

Videos
http://www.youtube.com/watch?v=SMtnZdwXaJs

http://www.youtube.com/watch?v=kVJHjs5Qt-M

If you cannot find the supplies I used or just want to change something I included Google sketch up files included for your modifications.
printing the ARM, ELBO, AND BACEPLATE are not necessary, I just use it as a desk fan.

The overview
The sensor shines LED's on the sensor disk and picks up the reflected light. The sensor disk is half Dark and half light (I used tape and white PLA) As the engine and the disk spins the photo sensor acts as a position sensor. The Arduino uses this date to tell what Solenoid pistons to fire. the Arduino cannot handle the current needed to turn over the engine so I used 2 TIP120 transistors on a 6V power supply 2 AMP.

You will need (all from RadioShack)
-enamel coated wire
-Arduino and power supply
-2 TIP120 transistors (and necessary circuit supplies)
-alternate power supply for solenoids(I used 6V 2 AMP)
-2 LED's

• photo resistor
• nails cut to length that fit into piston File
• switches
  good luck!