Hi,
I'm a software guy groping around in EE-land, and I could use a little help.
A few old inkjet printers yielded up some nice motors with optical rotary encoders built in. There are only six wires coming from the connector on the back of the motor/encoder. Two of the wires go directly to the DC motor. The other four are for the I-R emitter and the two I-R detectors. Here are some lovely photos, in case they help:
Even though it seems to work, I can't help but feel that something is wrong. I would have expected the two photodiodes to share a common anode or cathode, but that doesn't seem to be the case. Also, I'm puzzled as to why they would be connected in the direction that they are - so that I'd need a supply greater than +5V to read D1 and a negative supply to read D3?
Surely, I've made a mistake somewhere, but when I go back through the process of measuring and visual inspection, I end up with the same goofy schematic.
What am I doing wrong? I'm assuming that the detectors (on the bottom of the opto-interrupter assembly, closest to the circuit board) *are* two individual photo diodes. An EE at work suggested that they may be ICs with built-in amplifiers, etc...
Can anyone shed some light on this?
Thanks.
Mr. INTJ San Diego, CA