

As you can see we may have 10 lines with 6 places for holes - lets recognize every 2 places as 1 ternary value - no holes for O (0), left hole for N (-1), right hole for P (+1) and two holes are invalid and must not be used:

To build actual reader I purchased three 1-to-5 phone cable outlets in 1-dollar store to take "pins" from it


Scheme is really easy one - left hole will be connected to -5V and right hole will be connected to +5V. In 2007 actual reader board was finished and now I need to build whole device:
