Propeller and Encoder

chazbrazil

Im trying to use a Propeller to read an encoder I pulled from a dead HP printer. I included pictures of the encoder and the pinout on the back of the chip.
My problem is that I cannot find any literature on the encoder for what pin is what. Its just a linear encoder on a cheap printer, so I cant imagine it being this difficult. Any ideas would be great!

Thanx!

Peter Jakacki

No idea, but you can use your dmm on the diode setting to find the infrared leds which should indicate a forward voltage drop of around 1.2V or so (don't quote me). Once you find those then you can pump some current through them and identify the transistors. By the look of the pcb pins it may well be a single led and active phototransistors, best to trace those lines back to ground and vdd if you can. You won't hurt anything if you supply +5V through a 220R resistor.

*Peter*

Graham Stabler

I think you will find the two close together are the power to the led and the other four are power and the two quadrature signals respectively (these things are two components pushed in to a housing). I probably have the pin out at home because I hacked a HP printer but it was not dead when I did so hence I was able to measure the signals and voltages. Otherwise Peter's advice is sound.

One other thing, on the printer I hacked the quadrature outputs were analogue so I used a comparator to convert them to digital (set the reference to supply/2 using two resistors).

Graham

OzStamp

Hi Chaz

Check out http://sharp-world.com/products/device/catalog/index.html

As you mentioned that it is a HP printer it could well be an AVAGO part as well.

There is some text on the side of the encoder is it Agilent ?
Agilent is a HP company ( or was part of that group..)

The SHARP company has the lion share of the market when it comes to small linear sensors
as used in copiers printers... but they also make 5_000_000 variants so good luck with finding the data.
Hopefull this might help you a little to get started ..

Cheers Ron Mel OZ

Post Edited (OzStamp) : 2/25/2008 10:23:07 AM GMT

chazbrazil

Hey, thanks for all the really good info!