I recently had a lot of damaged printers to salvage, and I would like to use the top of page detection sensors that come with the printers to measure the rotation of motors with toothpicks atached to their axis.
and I thought that someone here would know about them and what is the way to operate with them. I have already tried every combination of connections of ground, detection and power (one each), including 5 and 3,3V provided by the arduino, but maybe the power supply just isn't enough, I don't know, and that's why I'm asking.
Well, its just a light detector, right? So you've got power, ground, and an output signal that will be high or low.
See if you can find a part number on the black part, then trace the signals out of it to the wires.
The link doesn't have enough info.
Should be a part like these, how many pins it has and what else is in the board could help narrow it down:
I have tried to serach the web for the ID on the detector, it is P1241 C57G the first is at the top line, and the second follows in the next line and is followed by : (two dots). The detector has 3 terminals, I thought as well that those might be ground power and detection. Doesn't have anything attached, just the connectors.
It is similar to this. And I comprehend that you might find awkward that it has only 3 terminals. Well... in fact, if I look at the bottom of the sensor I see that there are 4 terminals, but there's a piece of white plastic that covers everything but the terminals and then outputs only 3 connectors.
One more thing: I tried using analog input instead of digital, resulting in some irregular measurings in almost every combination of connections, not being related to whether there is an interruption on the light or not... I really don't know what's happening...
Look at page 3, the part is an optisolator with the light path open vs being normally enclosed.
Add some current limit resisters like on page 2. 390 ohm should do okay.
Then put 5v on the LED cathode and collector (pin1 & 3), should see a high on the emitter (pin 4).
Hey, I solved my problem in a different approach, using a phototransitor and a common visible laser pointing at it. Thanks for the replies, I will someday in the near future try to use the original detector for other applications.
