homemade encoder issues

we are having some issues while trying to make a single channel encoder using an NTE3100 (made our own 18 slot disk) <http://www.nteinc.com/specs/3100to3199/pdf/nte3100.pdf>. We think we have biased the 3100 thusly (we have tried with and without the 1 meg resistor)… <http://home.pacifier.com/~mcginty/nte3100.htm>

                 |+5VDC     |+5VDC
                 \          \  Both Resistors 
                 /          /  1 K ohm
                 \          \  Brown, Black, Red
                 /          /
                 |          |
                 \|        ---
                  |      &lt;-\ /
                 /|       &lt;-v
                 |         ---
                 |          |

Signal out----±-----+ ±—+
\ |
/ 1 Mega Ohm |
\ Brown, Black |
/ Green |
| |
___ ___
_ _

We get 4.95 V when high (unblocked), but only drop a volt to about 3.8 V, so we never go low.

We are hooked to a “digital sidecar” and cRio. <http://www.usfirst.org/sites/default/files/uploadedFiles/Robotics_Programs/FRC/Game_and_Season__Info/2012_Assets/Digital%20Sidecar.pdf> <http://www.ni.com/compactrio/>

Any help would be greatly appreciated.

Thanks, Chuck.

See my response in your other thread