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Author Topic: replace servos with DC motors?  (Read 2162 times)

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Offline kroninTopic starter

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replace servos with DC motors?
« on: March 21, 2009, 12:41:47 PM »
Hi. Im new to this robotic stuff, so i figured that i would start with the $50 robot, just to get some basics.
Unfortunately, where i live, the $50 robot is more like a $100 robot due to expensive parts - the cheapest servos i can find is around 20$ each, wich leaves very little money to get the rest of the stuff. :-[
however, I have a lot of small DC motors , so i was wondering if i could replace the servos with them? what modifications do I have to make to the schematics, if its possible to do?
I know the dc motors arent very strong, but just as a proof of concept, theyre strong enough to what Im trying to accomplish..
I dont know if this is the right board, but I dont want to double post, so im trying here first ;-)

Offline offy

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Re: replace servos with DC motors?
« Reply #1 on: March 21, 2009, 12:45:08 PM »
For DC motors you need a motor controller. A dual one controls 2 DC motors, they vary from $50 to $200. Servos would be cheaper to start out with since they plug right into the board.

Offline Webbot

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Re: replace servos with DC motors?
« Reply #2 on: March 21, 2009, 01:04:10 PM »
I have done a tutorial on creating DC motor controllers - so you can check that out. Do your motors have gearboxes? If not they may run VERY fast and have LITTLE torque - so as soon as you put the robot on the floor then the motors will stall.
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Offline kroninTopic starter

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Re: replace servos with DC motors?
« Reply #3 on: March 21, 2009, 01:51:09 PM »
wow - you guys work fast :)
I guess youre referring to http://www.societyofrobots.com/member_tutorials/node/163 for the motor controller tutorial? I will have a look at my electronic stuff and see if i have the parts needed to build one
now, maybe im not quite ready for this, but how do i make the circuitry to include a motor controller in the $50? it uses 1 pin for a servo, but either im misunderstanding something, or a dc motor requires 2 pins (but witch??)
Yes, i have gears for the motors (stripped an old RC), so i think that part is easy to solve.

Offline want2learn

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Re: replace servos with DC motors?
« Reply #4 on: March 21, 2009, 04:16:07 PM »
If you stripped an rc model, couldn't you use the servos from that? Very few rc models use only motors
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Offline SmAsH

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Re: replace servos with DC motors?
« Reply #5 on: March 21, 2009, 05:02:58 PM »
If you stripped an rc model, couldn't you use the servos from that? Very few rc models use only motors
i thought that was just the expensive ones? all the rc cars ive taken apart use dc motors?
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Offline want2learn

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Re: replace servos with DC motors?
« Reply #6 on: March 22, 2009, 12:44:48 AM »
I said model. ;) not toy
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Offline SmAsH

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Re: replace servos with DC motors?
« Reply #7 on: March 22, 2009, 12:49:49 AM »
ohhh sorry, my bad. yeah, i can imagine most of them would have servos. but why pay for the model when you can just buy servos? i can understand if you find a broken one but...
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Offline Admin

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Re: replace servos with DC motors?
« Reply #8 on: March 22, 2009, 06:43:03 AM »
http://www.societyofrobots.com/robot_faq.shtml#servo_motor

You can get decent dual packaged motor drivers for as little as $20:
http://www.pololu.com/catalog/product/1110

But depends on your current . . .

If you don't care about reverse, you can use a simple $1 MOSFET per motor.

But I personally recommend just buying the servo. Once you have it, you'll never have to buy it again.

 


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