I feel so stupid asking this question

I've been around robotics and controls all my life but the gray hair is
getting ahead of the gray matter. I know there is an h bridge joystick
controller out there at Radio Shack or somewhere... I want to steer a wire
controlled device left and right through a 9.5 volt geared motor and do it
by reversing polarity and running through a pot. Is a device such as this
available overnight from anybody?
What I have in my hands is an older Radio Shack RC car and we have lost the
transmitter so I need to fake a servo type control to the steering and drive
motor of the toy.
Wayne in San Diego
Reply to
Wayne Lundberg
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A standard DPDT with center off switch can be used to control the motor and direction. Spring loaded ones are a good choice. Check out Gateway, as they have a good selection of smaller switches. You'll probably find DPDT with center off, and the spring loading is a bonus. Some wire 10 minutes solder time and you'll be off and running.
The usual advice goes out about controlling speed with a pot. If you go this route, keep to smaller motors (1 amp max) and higher wattage pots. Otherwise you'll burn the pot out. The "real" way is to have the pot control an oscillator that is firing a FET. You can do it with a 555; look for schematics on the Internet that allow 50-100% duty cycle. Most of these add only a diode and maybe another resistor to the standard 555 hookup. You can build it on a cheap breadboard, and tape the breadboard to the bot. Gateway has small breadboards for $2.95. Look on the back side wall.
-- Gordon
Reply to
Gordon McComb
Thanks Gordon... you are great! But I'm an old geezer with shaking hand with a solder iron and think that there must be a forward/reveres, left/right two motor joy stick with built in rheostat or sliding pot that I can just buy and put to work. Any ideas? I've tried eBay and a whole lot of Google searching with no luck. Everybody has gone wireless!
This is a kind of urgent project in that we are developing a robotic/wire/wireless device to help in finding and destroying IEDs over there in the war zone... and doing it with an all volunteer, no budget, development crew. Want to join?
Wayne
Reply to
Wayne Lundberg
--Check out the College of San Mateo robotics page; IIRC the teacher had a homebrew wire-guiding system we could play with..
Reply to
steamer
Here is a candidate on eBay:
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#: 6289576579
I had no idea what the "MAME" is they are talking about, but the joystick in the eBay auction seems to be based on a couple of pots. When I Googled on "MAME" it turns out it means "Multiple Arcade Machine Emulator", which seems like a good search string to find some of the kind of joysticks you are looking for. One of them on this page looks like it is connected with "spade" connectors:
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Searching on "replacement joystick" led me to this page:
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led me to Google on "Happs P360 joystick", where I ran across this page:
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might be a good jumping off point to find what you need?
Also, here is a wheelchair joystick, which seems to me to be in the ballpark for what you need:
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#: 9532602580
Perhaps these pages will help you get what you need ! JCDeen
Reply to
pogo
This site has something you might be interested in ! Looks like a joystick with spade connectors for about $12.00 ! Good luck !
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JCD
Reply to
pogo
Hi Wayne, I have not seen anything like that commercially availible for a low current 9.5V motor.
For bigger stuff, see:
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I picked up a couple of Curtis/PMC's drivers from a surplus place, but don't see which one on my paperwork.
Roboteq would be another place to look at big stuff.
I wrote an article for the Seattle Robotics Society in '98 or so that had a good solid PWM Generator that would tie into pots just fine. Unfortunately, they don't show anything before '99 on their web site any more. If all you need is a few amps (less than 3) it would be easy to use the PWM generator(s) to drive an H Bridge IC or two. This is not going to be an over-night deal. The only way I know of to get fast and reliable is to spend real money. If you are interested, please email me and I can send you a PDF of the article.
Another approach would be to generate signals mimicking the RC type servo signals and drive hobby servos for steering and a hobby speed control for forward/reverse. This approach can be done easily with a dozen or so components.
I am curious about your IED destruction project. Do you have a web site or other accesible documentation on it?
Regards, Bob
Reply to
MetalHead
Is it here? :
dpa
Reply to
dpa
Thanks! Yes, it was in the October '99 issue:
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I looked at their site a couple of months ago and do not see this. I though it was gone.
Bob
Reply to
MetalHead
---snip---
Thank you one and all for all the great insight and help in finding a joystick type thingie.... Here's what I will be trying out because the model must be working by Monday at least partially... Bought a battery holder for 8 AA batteries, will make a sliding contactor to draw current from two, four, six or eight batteries in series through two DBDT switches, one for the drive, one for the steering. This will allow us to perform some experiments while researching the next phase of development, most likely a wireless close-in LAN system. Not as slick as a joystick. It will require a bit of dexterity, but what the heck...
Wayne
Reply to
Wayne Lundberg
Hey guys,
James here from RetroBlast.com, the site referenced in pogo's post below.
I thought I might chime in and say there is an index, or roundup, of our joystick reviews here:
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Also, we recently ran a brief news item about a company that sells some very interesting industrial joysticks. You may find something there that will work for your projects.
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Lastly, there is a great site called "Build Your Own Arcade Controls" that hosts a forum for folks building custom arcade systems.
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They recently began a WIKI dedicated to this topic and have a great section on arcade - style joysticks that may help in your research.
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Very Best Regards,
James McGovern Managing Editor RetroBlast! News and Reviews
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pogo wrote:
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Item #: 6289576579
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Item #: 9532602580
Reply to
james

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