I've dissected a few mice before, and their encoders aren't especially
easy to interface. I'm looking for something with absolute position
readout, and something more unified than just a baffled emitter/receiver
pair on a breadboard.
Not all optical (i.e. some Hall-effect, etc.) but maybe worth a look:
I>>>s anyone aware of a small, cheap optical encoder for use in measuring
I vote for US Digital, though, nothing that has absolute positioning
capabilities is going to be THAT cheap. If you're willing to dial in the
home position on startup, then a regular quadrature encoder is fine. They
even sell counters that hook up to their products, thereby giving you the
Wow, thanks for the references. I noticed some offer linear as well as
rotary position transducers. My end goal is to measure the position on
armatures, ones too small for practical use of servos. Could anyone
recommend the best method of motion feedback in this case?
OIC. Well, the "cheap" part of the equation is why I suggested a
mouse. The absolute-position optical encoders tend to be expensive.
It's much cheaper to use a simple quadrature encoder with a micro
attached (doesn't have to be anything major; an 8-pin PIC is perfect
for the job). And the cheapest optical quadrature encoders are in
The huge majority of nowadays optical mouses don't use optical
"encoders" anymore. They use optical chips that have a built-in
CMOS sensor and DSP which processes the successive images to
detect the motion. Absolutely useless to mesasure rotation, although
they can be used to measure translation - as long as you only need
a relative, and not absolute, position. You may need to use a specific
lens instead of the plastic lens used in mouses, according to the
distance between the chip and the moving area.
These chips aren't so hard to interface. Most of them are made
by Agilent: just take a look at their web site to find the data sheets.
There is no such thing as a cheap optical encoder, unless you build it
Although, they typically have optical encoders on ebay from time to time at
Some of the other guys posted links to where most of the encoders are found
already, so i won't burden you with
any more. :)
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.