quadrature optical encoder no signal - weak signal


I’m trying to read out a quadrature encoder I salvaged from an old printer.
I couldn’t find the right data sheet.
The only inscription I could find is “Agilent 18”
and there are two other 4 digit numbers.
But as I got several of these encoders and the numbers don’t seem to have anything in common.

As far as I can tell they are similar to the Agilent AEDS-962x just in a slightly bigger package.

I get the LED in the encoder turned on, and all pins connected and as I connect it to the Arduino Uno I got some code from the playground running. As I didn’t had the disk installed the expected 0 was displayed, but as I installed the disk or blocked the slot I don’t got any change.
Vcc and Ground were supplyed by the Arduino.
As I connected my power supplyI got some random changes,
which are properly caused by the swich-mode power.

I connected LED’s to the output channels and they turn on, due to the pull-up resistor in the encoder, as all pins are connected.

My problem is they won’t change state, as I block/unblock the slot.
I suppose they should turn off, when the slot is free.
With the multimeter I get a voltage change between channel A and Vcc of about 30mV.

I triedat laest the experiment with the LED’s with 3 sensors several times.
So if someone could guess what I’m missing I am really keen to hear it.

I’m trying to solve this for several month so don’t hesitate to answer even if this post is aging.

Thank you for your attention.

DSA00475157.pdf (193 KB)

Please post a hand drawn wiring diagram. The data sheet you posted does not have one, and is rather useless.

You may need pullup resistors on the outputs, and almost certainly need current limiting resistors for the encoder LEDs.

Thank you for your answer,

I got a 220R resistor for the encoder LED.
The other LED’s shouldn’t need one, as there is a pull-up resistor in the detector integrated.
For the experiment with the Arduino I connected the two Pins going to the LED’s to Pin 2 and 3 on the board.

I hope the wiring diagram is helpful.

PS: I tried external pull-up resistors to no effect.

The LEDs are on the encoder outputs are a bad idea, and are probably reducing the output voltage levels so that the Arduino inputs never see a logic HIGH.

Remove them and try again with the Arduino.

I didn't use both at the same time (either LED's or Arduino in their place).

I came up with the LED's because I suspected the sensor didn't work right. It's only a troubleshooting experiment.

Please have a look at the "How to use this forum" post for tips on how to get help. It all starts by you providing the basic information required to troubleshoot the problem.

I will try to provide all information related to this problem.
Please excuse the lack of some details, but I’m not native to elektronics and therefor don’t know exactly which details could be related to this problem.

I am happy to answer the questions and provide additional information.
I hope my posts are readable.

Maybe I couldn’t make the setup clear enough.

So for better visualisation I added a picture of two sensors.
On the left sensor I only removed the black cover.

The resistors on the right sensor are not used any more.

The current limiting resistor has a way to hight value and the other two are the external pull-pu’s I mentioned earlier.

Anyway thank you for your answers so far.