Measuring displacement using linear encoder from printer

Hi all,

In another topic (this one) I tried to get accurate distance measurements using an optical distance sensor. This turned out to be not accurate enough. I only got 0.5mm along with some other trouble.

EDIT: Adding range requirements: The distance from the sensor to the object @stationary (midpoint of oscillation) : 40-60mm The range the object travels when oscillating : -25mm to +25mm

This measurement requires flexibility, literally. The object is oscillating @ 0.5Hz to 4Hz and the flexible strip from the printer moves nicely through the sensor at this range. /EDIT

I would now like to try using an encoder strip from a HP printer. I took it apart and salvaged the strip and the circuit board with the encoder. I hope someone could help me a bit with getting this thing connected to my arduino

Click the image for high res

As far as I understand there should be: - One IR led - Two pairs of signal pins

Also I took off the housing. By accident when I tried to de-solder it from the board, which is not gonna work btw :s

Anyway, it gives a nice look inside and I tried to figure out what was connected where:

Click for high res

Pin 1 Is connected to a resistor that is probably connected to gnd

Pin 2 Pin 2 is connected to an external connector, probably V+

So pin 1 and 2 seems obvious, a led connected to V+ and to a resitor to gnd. Yay.

Pin 3 Cannot see where this is connected to.

Pin 4 connection 1

Pin 4 connection 2

Pin 5 Cannot see where this is connected to.

Pin 6 I guess it's connected to gnd.

My questions: - what pin does what exactly (for pins 3, 4, 5, 6) - How could I hook it up to my aruino ?

De-soldering is not an option, could I scratch off or cut all the leads on the board and solder my own leads to the pins ?

Thanks for reading !

Over what distance do you need this?

Those cheap digital calipers have a serial interface on them. Down to a thousandths of a mm (10^-6 m), or in some, half of a thousands of a mm.

polymorph:
Over what distance do you need this?

Those cheap digital calipers have a serial interface on them. Down to a thousandths of a mm (10^-6 m), or in some, half of a thousands of a mm.

I would second this suggestion - there’s been a lot of work done with them, and the techniques are well documented across the web.

polymorph: Over what distance do you need this?

Those cheap digital calipers have a serial interface on them. Down to a thousandths of a mm (10^-6 m), or in some, half of a thousands of a mm.

I know about the caliper option.

The distance from the sensor to the object @stationary (midpoint of oscillation) : 40-60mm The range the object travels when oscillating : -25mm to +25mm

This measurement requires flexibility, [u]literally[/u]. The object is oscillating @ 0.5Hz to 4Hz and the flexible strip from the printer moves nicely through the sensor at this range.

I do not need a thousandths of a mm precision, 0.1mm accuracy combined with fast readout time is my goal.

I would really like to use this component to get my project going.

Thanks

The Hakko 808 can desolder virtually anything, often without damaging either the board or the component. It's good at sucking out the solder that wicks down plated-through holes and becomes unreachable to a normal iron.

One of the best tools I ever bought. With other tools you have to choose to destroy the board or the component and focus your destructive effort there.