Optical Sensor vs Optical Encoder

The first one on the page includes a 1/8" steel shaft. You might put a knob on the end of it for a manual control of some kind. The next one accepts a keyed shaft, as I gather it.

These are some of the most outrageously expensive units I've seen in my life, though. I guess you really pay for the 1024 PPR. But I'd consider the idea of learning how to make my own at that price and then go into a business competing with them. Sheesh!

Jon

Hi, Mr. Kirwan. Sadly, these *are* reasonably priced. BEI has a reputation as one of the most reliable industrial optical encoders, and they always are within specified tolerance.

Thus it has always been. Precision optics (they photomask the quadrature pattern onto a glass disk), a small electronics board and a lot of manual assembly labor. If you can figure out a way to beat their price, I'll be standing at the head of the line.

Cheers Chris

Oh, $200 isn't so bad. They can get a lot more expensive that that. I've used one that returned absolute angle with a precision somewhere in the arcsecond or milliarcsecond regime-- sitting still on a fixed shaft, it showed constant angle fluctuations from the vibrations in the floor and the air. The glass disk reflected rainbow colors, like a CD. I'm not the one who bought that one, but I know the price tag was in the thousands.

Then I wonder why Mouser put the Optical Encoder under Sensor category. Pls check it out in mouser.com

I wasn't disparaging them, only noting the cost compared to lower resolution optical units I _have_ purchased before (32 and 64 counts per rev) for knobs (at $6 each, btw.) I've used 1024PPR encoders before for an infusion pump tester, but someone else actually did the design and purchase of them, so this was a surprise to me. I accept your point that this is reasonable, if too high for anything I'm likely to care about in hobby work.

It does make me more interested in dismantling them, though.

Hehe. You are buying these things, too?

I need to look at the complexity of solving the etched/photomasked issue. Sounds interesting to think about, anyway. Thanks for the info.

Jon

OMG! Now there is an idea! Picking the right CDROM/CD writer combo and then writing a certain pattern on the disk, using those smaller CD ROMs that are sometimes used by vendors. Then the right pickup design for decoding the pattern into pulses.

Could even purchase the manufacture using custom disk sizes and pressed patterns.

Hmm.

Jon