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Cool switch

kelvin jameskelvin james Posts: 531
edited 2005-11-30 18:58 in Robotics
Howdy Thought i would pass this little info on that i picked up on one of my google excursions. It is a miniaure trackball made by ITTCANNON , and it is pretty neat. The ball is only 8mm ( 5/16 in.) and doubles as a select switch to boot, press the ball down all the way and it acts as a switch. Beside the obvious uses like a navigation for menus and such, i thought it may be useful for some of those who are looking for a way to positionally track their robots movement of a 2D surface. Basically, it is a X / Y encoder, which the pulses generated can be output to the stamp to know how far it has travelled in any given direction. That info can be used for positional mapping of the area. Now, there are some issues with friction force to make sure the ball is always turning with with the movement of the bot, so the type of surface contact would be of concern, like probably wouldn't work on carpet, etc. I think, if the ball was mounted on a spring force lever to the ground, to hold the required pressure needed for it to turn properly, it might work. It has 12 counts per rev, which doesn't seem like a lot, but considering it's size, it would probably be doing around 120 counts comparable ratio wise to a rev of the bots wheel (3in.). 120 might be too much much for the stamp too handle from both axis, not sure, but speed of the bot will be a factor. So, not great resolution, but not bad. Another good point is that it's electro-mechanical, so it consumes no power to run, like an optical does. Life span is not the best encoder-wise, around 300,000 cycles, but it should be good for a while. And the best part is that you can buy one from mouser for 5 1/2 bucks, so replacement is not a big deal. I'm not sure if it will work for the bot navigation thing, but thought it might be an idea worth trying. I'm going to get a couple to try, and if anything, they will make nice little controllers. I included the pdf, not a lot of info, shows all the specs.

kelvin
www.ittcannon.com/media/pdf/catalogs/Leaf/SW_nav_trackball.pdf

Post Edited (kelvin james) : 11/30/2005 6:55:34 PM GMT

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