What is this?

I have recently taken apart a printer for the stepper motors, dc motors etc. I then came across this tiny circuit board. I think it is some kind of sensor that sensors the paper going through it but im not quite sure. Has anyone seen anything similar or know what it is?

it wont let me add my own images but it looks exactly the same as this:

Looks like an optical sensor... Ir emitter on one side, ir sensor in the other, and paper goes through the middle blocking the light

I thought it was!

Thanks for the quick reply!

$20 sounds a lot for it. Just saying.

With spares you are paying for the administration and storage more than the part!

it wont let me add my own images but it looks exactly the same as this:

Are you trying to say you don't know how to upload photos to a forum post ?

No I do know but the file was too because big and I want messing around compressing it and I salvaged it from a printer so I won't need to buy one. Anyone have any idea where I will be able to find the pinout???

Shpaget: $20 sounds a lot for it. Just saying.

Hey, if that is the part you need to repair your printer, you will pay the money!

(Mind you, I have purchased new printers for less so I have no idea why that printer would be so valuable as to warrant repair in the incredibly improbable event that sensor failed.)

mitchK: No I do know but the file was too because big and I want messing around compressing it

Is that gibberish to say you couldn't be bothered? :roll_eyes:

mitchK: Anyone have any idea where I will be able to find the pinout???

You are kidding! :astonished:

This is an Arduino forum. If you do not have a breadboard on which you can set up a 470 ohm resistor and a series LED to probe for the IR LED in the photo-interrupter and then write a sketch to relay an input with INPUT_PULLUP to relay the photo-transistor state to the Pin 13 LED while you try the connections, then you aren't worth your salt!

Of course I realize the cost is not just the cost of the part. Paul, the link you provide is... unexpected.

No I do know but the file was too because big and I want messing around compressing it and I salvaged it from a printer so I won't need to buy one. Anyone have any idea where I will be able to find the pinout???

So you're saying it is too much trouble to right click on the file and select "Open with:/Paint , left click on "Resize" , type in "50" where you see " 100%" and click on the SAVE buttone (floppy disk symbol) (which takes approximately 30 seconds)

Is that what you are saying ?

It's the same as any other opto switch. You'll have to figure out which side is which - but there's tons of stuff on them. One side gets power (through a resistor, which may or may not be on the board) and ground, other side gets a signal (needs a pullup) and ground, and the signal gets grounded when the light is present. Best way to determine the pinout (if not marked) would be to look at how it was connected to the rest of the printer.

Hi,

I recovered the same sensors and I'd like to know if someone managed to use them. I think I got the pin configuration by examining the board but I could'nt manage to use it : there is neither interruption on the data pin nor IR code reception. When I read the stream as if it was analogic, I can see that the sensor is light sensitive. I am unable to bring this further. Would anyone have a tip ?

these photointerrupters usually have an IR diode on one side and the other side is usually a phototransistor.

You need to power the IR led to receive anything of value (or lack thereof). When the beam is broken you will sense a change in the output at the photodiode or phototransistor or whatever they used on that side.

These days most are phototransistor so you don't need any additional gain stages.

Try them out... the IR diodes have a forward voltage that's usually pretty low similar to a RED LED (about 1.6-1.8V), run them at about 20 mA.

Test to see which is which - use your meter to find the diode junction... looking for about 1.7V drop.

You can use your phone camera to see the IR LED's to see if it's working.

If it helps some phone cameras can pick up infra-red LED light (esp cheaper phones), so try phone in video mode to test the LED glowing? Not guaranteed, but may help.

Thanks for your answers. It's actually quite easy to find the pin configuration since there is a built-in resistance to power IR led. I powered the led with 3 volts but was unable to pick up any IR light with my camera. Same with 2 other sensors of the same kind. I am pretty upset with this things right now, I might try again another time...

As I said only some cheap phones can see IR, the good ones filter it out completely...