Subject:
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Re: some [Q]'s (fwd)
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 23 Oct 1996 06:48:32 GMT
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Original-From:
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Matt Harlan <mjh10@cornellSPAMCAKE.edu>
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Viewed:
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1576 times
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Yoni,
> 1) In the "How to connect DC motors to HB" paper, it says to use .1 inch
> male headers to connect the wire leads to. Can anyone give me a less
> general specification for these male headers?
Use snapable male header strips. They come in lengths from a few pins to
more than 30. They're simply .025 inch square metal pins stuck in a strip
of plastic on .1 inch centers
| | | | | | They kinda look like this.
===========
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| | | | | |
Cut a section of three pins and pull the center one out.
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=====
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> 2) Is there any way to connect more than four motors to the HB without
> adding a motor controller chip or expansion board?
You could hack a little with the board and split up the H-bridges, then you
could drive 8 motors independently, but only in one direction. Not very
useful.
Add a 'hc374 and another driver, its more practical
3) Is the knob easy enough to use as an encoder??? (seems a bit tough to
> move)
I guess it's possible. Limited range of motion. HB must be close to what
you need to encode. You're better off using one of the A/D ports if it's
analog, or an IC line and an IR relfection sensor.
> 3) Can anyone give me a reference to a supplier of cheap sensors, such as:
> i) IR sensors (proximity)
> ii) any range sensor (what's best?)
> iii) easy-to-use encoders (can do analog, so would u suggest
> potentiometers to measure how far up or down a shaft goes?)
> iv) photoresistors
>
>
As far as IR, check out Mobile Robots. There's a simple sensor using a
'hc04, an IR LED, and an IR recieve you can get at Rat Shack. The code for
using the sensor is also in the book. I use it and it works for me.
For ranging I use a Polaroid 6500 sonar set-up.
Picked it up from Wirz Electronics for $50
http://www.cec.wustl.edu/~blw2
You can use the sonar without the expansion board, but you'll lose two
motor outputs if you connect the sonar so you can use the code avaliable in
the cher archive.
A pot will work for postion as long as the range of motion is limited.
Could use a linear taper or a log taper, if one end of the motion needs
more accuaracy. I don't know exactly what you have in mind, but if you're
trying to move something to a desired position, try a servo first. You can
just set it and forget about it, it'll do the rest.
I think you can get photoresistors and Radio Smack. Also, try some of the
surplus companies.
All Electronics
http://www.allcorp.com/
That's the only one I remember off hand for surplus.
Digi-Key and Mouser also have sites, more expensive though.
http://www.digikey.com/
http://www.mouser.com/
could try
http://www.jdr.com/
or
http://www.jameco.com/
But, it's probably easier to go to radio shack.
Hope it helps
matt
_______________________
Matthew J. Harlan
Cornell University
Electrical Engineering
mjh10@cornell.edu
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