Codewheel Generator for Homebrew Optical Encoders

Jun 05, 2008 29 Replies

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The magnetic pickup contains it's own magnet like a guitar pickup, and the flywheel has to be ferrous like guitar strings. bg

can it do this?

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martin

Heh. Clever indeed.

Rich Webb Norfolk, VA

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I get the rest, but where's the "3" ?

Cheers, James Arthur

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Oops, got it. Doh.

--James

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The innermost arc goes 3/10 of the way around the circle. JF

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Thanks -- I'd missed that.

--James Arthur

Nice one, I've created them using FastCAD but this saves a lot of hassle, especially for Gray encoders.

Just a little request: an option to fill the page by step-and-repeat when printing?

JS

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I once saw a thing on teevee where the two guys who had been making all of the "crop circles" show exactly how they did it. It's trivially easy to walk through a grain field like that without leaving a trace - just walk between the rows. And you can make a perfect circle by standing a guy in the center with a rope, and you can figure out the rest.

But even after seeing that, the True Believers refused to believe that the "real" crop circles were a hoax. ;-)

I'm thinking of making sort of a mask of that Jesus pic,

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, and scorching it into a tortilla, and sell it on ebay: "Jesus on a tortilla Hoax!" - it'd probably sell for tens of thousands. ;-)

Cheers! Rich

That feature occurred to me the first time I looked at that lonely little wheel in the center of the page. Then I thought that it would be hassle enough to make one encoder. Who would ever want more than one copy?

After trying to punch an accurately-located center hole, though, I quickly realized why someone might want more than one. (It took me three tries.)

So, I'll consider the feature for a possible future upgrade.

Thanks for your suggestion.

BTW... a bit of irony...

I ordered some tiny SMD phototransistors from Electronic Goldmine to use in my homebrew encoder. With the transistors, I also ordered some junkbox filler parts to fill out the order enough to make the shipping costs worthwhile.

One of the add ons was an assortment of pots, since I thought I'd be tearing more than one apart before I figured out a good mechanical codewheel mounting arrangement.

Included in the pot assortment were two quadrature encoders! One a Clarostat 128 CPR encoder, the other a beautiful Bourns ball bearing

256 CPR encoder.

I hope to find time to test them this evening. If either of them work (particularly the Bourns), I won't have to fiddle around with a homebrew encoder.

So there's irony for you. I bought the pot assortment as a throw-in of project parts, and acccidentally received encoders that might eliminate having to build the project at all!

There must be a lesson there. :-)

Tom

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