Note: This is an old schematic. Please see the latest schematic.
I drew out the display schematic using ExpressSCH from ExpressPCB. In this design, I proposed a Schmitt Trigger. I have not tested this yet, but it should help clean the signal.
I also received some information that maybe more current should be going through the signal wire. I will have to think about this for a while.
I made a PCB design too. If I decide to make another unit, I will order the PCB. When I know it will work, I will post that file and the code for download.
UPDATE: The signal seems fairly clean coming into the unit. I did have significant problems with power, so I had to add some big capacitors.