What is this?

Thread Starter

timelessbeing

Joined Jul 5, 2011
18
Unfortunately that's all I have. Possibly a printer or scanner. There is a stamp on the back of this PCB fragment that says CMKD-P3X and a date 2003.6.2. I looked it up and came up with nothing.

Some kind of EPROM?
 

bertus

Joined Apr 5, 2008
20,571
Hello,

I think that the black strip is to small for a fingerprint reader.
Where the fingerprint readers available in 2003?

Bertus
 

THE_RB

Joined Feb 11, 2008
5,438
It's a simple light sensor, probably with "light to frequency" output. The sensor component only has 2 wires going to the chip, so it is a simple monochrome photodiode or LDR.

If you power the board up you will probably find one of the chip pins is a frequency output that changes freq according to light level.
 

Adjuster

Joined Dec 26, 2010
2,148
The device we are assuming to be a sensor appears to have only one bond wire contacting it, and a common connection. Is it not more likely to be a single photodiode?

Edit: Oops, someone got there an hour ago.
 

SgtWookie

Joined Jul 17, 2007
22,210
From what little I can figure out, the board came from a DVD player.

I believe that the IC you have there was used to determine the position of the laser head.
 

THE_RB

Joined Feb 11, 2008
5,438
From what little I can figure out, the board came from a DVD player.

I believe that the IC you have there was used to determine the position of the laser head.
Interesting! Do you know that or it it a guess? I've never seen a sensor of this type used for laser head positioning, normally they position by finding focus on the ident track on the DVD and some units may have an optical interruptor sensor on the mechanicals.

I still think it's an ambient light sensor (and yep that's a guess!). :) Some appliances have autodimming of the display at night and the ambient light sensor is used for that. In which case it probably would have been on the front panel PCB with a little window.
 

DerStrom8

Joined Feb 20, 2011
2,390
I agree with Sgt. Wookie and The_RB. It could be used in a DVD player, CD player, or it could be used to calibrate a laser printer. I've seen them on all sorts of electronic devices, all of which have something to do with a laser. Optical Mice usually have one built into a larger chip, used to decode the signal. I haven't once seen one in a mouse separate from the other components. My money is on the CD player or the calibration circuit for a laser printer.
 

Thread Starter

timelessbeing

Joined Jul 5, 2011
18
There's a very good chance it came from a laser printer. I DO remember disassembling one. Since there's an IC, does that mean output would be digital?
 

thatoneguy

Joined Feb 19, 2009
6,359
There's a very good chance it came from a laser printer. I DO remember disassembling one. Since there's an IC, does that mean output would be digital?
No, just different voltages out on the two wires connected to it depending on which horizontal "ribbon cell" section the laser hits. I'm assuming that if you look very closely, you'll see hundreds or more small lines across the narrow side from top to bottom. Each is a photocell that will output a slightly different voltage when illuminated, so the output of it will "say" where the light is pointed at on it by a different voltage.
 
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