Magnetic levitator shield for arduino nano.

This shield is for use with ojbect:

• Ekobots - Levitator with arduino.
  http://www.thingiverse.com/thing:1392023

• You can order the shield at:
  https://oshpark.com/shared_projects/kxH3Ak1b
  It was published in OSH Park by Thingiverse user krwynn:
  http://www.thingiverse.com/krwynn/about
  Thanks!

All you need:

• 1x Arduino Board (Nano to use the shield);
• 1x Electromagnet - ZYE1-P25/20 12V, 25mm diameter, 20mm height (ebay $7.00);
• 1x Linear hall effect sensor - 49e (ebay Kit 5 - $1.50);
• 1x Magnet cube 10mm (ufo_1) or magnet sphere 10mm (ufo_2);
• 1x Darlington Transistor NPN - TIP120;
• 1x Resistor 1K ohm;
• 1x Diode N4007;
• 1x Power supply 12V 1A (ebay $2.00);
• 2x Micro switch;

Arduino firmware:

• Levitator.ino - For normal people, with life and girl friend;
• Levitator_PID.ino - If you do not have life and girl friend or
  if you have any kind of mental disorder, it was made for you... ;-).
• I am testing a new firmware with safety mode, it turns off the
  electromagnet in case of fall of the permanent magnet.

Working mode:

• The switch "+" increase the distance from the electromagnet.
• The switch "-" decrease the distance from the electromagnet.

My videos:

• Video 1 (3x block magnets 10mm x 10mm x 3mm + 8mm x 30mm threaded rod);
  http://www.youtube.com/watch?v=w-jtu5cxl9o
• Video 2 (1x cube magnet 10mm + Ufo 01 3D printed part);
  http://www.youtube.com/watch?v=nXplyDKqs2s
• Video 3 (1x sphere magnet 10mm + 8mm x 30mm threaded rod);
  http://www.youtube.com/watch?v=AxjHF56DeiQ
• Video 4 (1x cylinder magnet 20mm x 5mm):
  http://www.youtube.com/watch?v=NttqFqB-nu4
• Video 5 (2x cylinder magnets 20mm x 5mm):
  http://www.youtube.com/watch?v=AIz9ystIPUo
• Video 6 (2x ring magnets 19mm x 5mm):
  http://www.youtube.com/watch?v=k7yBUj8GIgU
• Video 7 (1x sphere magnet 10mm + Ufo 3D printed):
  http://www.youtube.com/watch?v=3VHKrIAETCA
• Video 8 (Prototype version test):
  http://www.youtube.com/watch?v=HpFQfXAwKzI

Attention:

• See the images to mount the hall effect sensor;
• The electromagnet alter the sensor real value for the permanent magnet;
• Mount the hall effect sensor as far as possible from the electromagnet;
• Use neodymium permanent magnets (it will not work with common magnets);
• Use soft wires to make easy the assembly, small box, remember;

That's all folks!