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Topic: Please help me identify these two components from a printer (Read 900 times) previous topic - next topic


Oct 11, 2011, 02:27 am Last Edit: Oct 11, 2011, 02:52 am by enjoyaol Reason: 1
Hi ! Got these two components from a printer. Maybe you can help ? :) I'm not sure what it is.

First is some kind of two-pins module with something which looks like an LED but with an enclosure around. Not sure that's an LED though, because it was inside the printer...
Edit: Ok I used a multimeter, it's a photo resistance

The second component is that : (no clue what it is, it looks like a switch that activates when something passes through ?)

Thanks for your help !


they look like paper feed sensors.

They typically have an LED on one side ( infra red sometimes ) and a photo diode on the other to detect when the led is on. A flag or light blocking arm or actuator is used sometimes to block the light. A sheet of paper hits one side or end of the flag to raise or lower the actuator into or out of the path of the light to detect paper movement inside the printer. It just depends on the make , model and manufacturer.


I think the sensor and emitter are in the same side. Without a white paper there is no reflection on the other side, which is black and with a paper enough reflection triggers the sensor. If the sensor is opposite of the emitter, then a sheet of paper can't quite block the IR emitter. Just my 2 cents.


In my printer, I found parts like that too. A ribbon with very find stripes ran between the two arms of the device and the ribbon was connected to the print head. Therefore, i believe it was a system to detect the precise potion of the print head. In this case, I think the emitter and sensor were on opposite sides.

With a lot of luck, I managed to dig this up.

PS: Please post back if you figure out how to make these work with an arduino.


If you look on the last picture, you see a device on one side of the slot with 2 connections. This is an infrared LED. It's probably powered by 5V.

On the other side you have the receiver. It has 4 pins, two of them are supply voltage (5V and GND) and the last two are the two quadrature outputs.

Trace the connections the PCB to find out what is for what.

Google Quadrature on the forum and you'll find code.

The fine plastic strip with fine stripes on that sad in the printer works with this (or the wheel, don't matter)

Happy hacking.

// Per.

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