Mouse motor encoder / robot interface

mlw · 2005-03-28T12:42:37+00:00

I have been thinking about this for a while, and am working on bits andpieces in the form of a "HOWTO." Between work and family, it is takinglonger than I thought.I was stalled on my robot because I needed a cheap counter/timer rig tohandle the encoders. I was looking around for something that was easilyinterfaced to a PC, but was well below the $100 mark. (Remember: sub $500robot.)Then someone suggested that I sit a mouse on each of the wheels. While itwas an interesting idea, it lacked any sort of mechanical integrity. I did,however, start thinking about what an old roller ball mouse was. The are,in essence, an unpowered two wheeled robot. Right now, the plan is to extract the LED and detectors from a mouse andeither modify a drive train to incorporate them directly, or create an easyto make encoder housing.The interface will be PS/2, USB, or even serial. These devices should bearound for several more years and can be had for about $5.00. On top of theencoders, the button could even be used as touch sensors. (It is humorousto think of your robot as a big mouse)Another big advantage of using a mouse like this, is the availability ofsoftware for testing. You don't have to write any code, simply use a mouseprogram. On wheel will go left or right, the other wheel will go up ordown, the buttons will show up as menu items.What do you think?

Mar 28, 2005 24 Replies

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blueeyedpop 21 years ago

well,

I am a died in the wool IsoPod Addict (

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). A Plug A Pod could to it with a lot of extra addit'l hardwaare available for other things. A tini-pod or could do it too.

Using an embedded micro is a very good way to augment a PC based system. Unless you go adding cards, writing your own dll's etc, a micro is the way to go.

I see a lot of Pods being used for just this purpose. A little bit of effort, and you can build a dedicated protocol for motion control , GPIO, A/D, other timing , and even CANBUS communications.

Mike

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Gordon McComb 21 years ago

There ARE ready-made controllers that do exactly this, but it all depends on what you mean by a "reasonable price." JR Kerr has long sold a set of PIC chips for motion control, with some fairly sophisticated tuning parameters. Is $30 reasonable for the chip-only version of their product? Seems to me it is, but others might consider that expensive. They don't offer the source code, for obvious reasons, so if you're doing a 10 axes animatronic controller, costs will add up. (OTOH, at $50/hour for a programmer, that's only six hours of work. Cheap for a full-blown PID system.)

I know of at least one regular poster here who's company plans to bring out a similar typer of product. But I'll let him announce it publicly. I see it's not yet mentioned on his web site.

-- Gordon

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EA 21 years ago

Just saw your post and thought you might use some info. I used the same setup you described, and have code examples, PS/2 spec., electronic interface, mechanical setup etc. on my web pages at

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both PS/2 and RS232 mice, and it worked great.

have fun,

eyal.

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