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Offline ROVERTopic starter

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wiring help
« on: December 08, 2012, 05:13:05 PM »
could you guys help me out how to determine the wires inside my rc truck, i decided to remove the circuit board of my remote truck and bought this dual dc motor controller, I just need help wiring it to the dc motors and im kind of loss, the steering motor has a white and red wire and the rear dc motor has 3 wires, brown blue and black wire, I hook up the power wires the black to ground and the red wire to 5 volts, the remote truck is powered by a 9 volt battery,  did i do that right?

Hoping you could help me out thanks!

this is the link for the motor controller

http://www.ebay.com/itm/110953019447?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649









Offline jwatte

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Re: wiring help
« Reply #1 on: December 08, 2012, 09:06:39 PM »
Hoping you could help me out thanks!


It's impossible to see what is going where on that picture.

From the top picture, I would say that blue and brown are the power leads for the motor, and black is a sense lead that senses whether the motor is turning or not (to avoid stalling out for too long, perhaps?) I've noticed that kind of lead in other RC motors, too, and measuring them shows a waveform related to the motor spinning. The fact that the wire is much thinner than the power wires means it's a control/signal wire, not power.

When you say "steering motor," do you mean "servo" with a rotating horn that drives the link arms that pushes the steered wheels left/right? A servo does not run from a motor controller (typically) but instead from a microcontroller or servo controller, as you typically give it ground and power on the first two wires, and a PWM control signal for how much to steer on the third wire.

Offline ROVERTopic starter

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Re: wiring help
« Reply #2 on: December 09, 2012, 12:12:37 AM »
oh great i noticed the steering motor has 2 thin wires, it looks like a servo as it has a horn that turns two links to move the tires in the front shouldnt be 3 wires if it is a servo? I only see white and red wire that is really thin i dont see a third wire, and here is the picture of the motor controller if you could help me out identify how to hook it up i would really appreciate it




Offline jwatte

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Re: wiring help
« Reply #3 on: December 09, 2012, 01:11:14 AM »
For the drive motor, it's easy: Ignore the black wire, and send the blue/brown wires to the first motor output of your controller. When you tell the controller to "go" on that channel, the motor should go :-)


If the servo is non-standard, I don't know how to control it. There are a few ways to run a servo (or even a motor) as a steering thing with only two wires that I can think of:

1) Use a spring that makes the wheels turn one way. Use a regular motor to counter the spring, with stronger PWM the more you want to counter it. If this is the case, you can control that motor from one of the outputs of your controller.

2) Use a centering spring, and give the motor some power to turn either way. Again, if this is the case, you can run it with your motor controller.

3) Use the wires for power and control, and send ground through the mounting chassis. As the chassis looks to be plastic, this is unlikely in your case.

4) Use a digital modulated signal on top of the power signal. If this is the case, give up on that servo and mount your own, because trying to work out something that can control that correctly would be way too much work AFAIK.

Because turning is easier than propulsion, the wires are thinner, because the "steering motor" (whatever it is) probably is a lot weaker, so less current is needed.

Try measuring the motor with an oscilloscope or volt meter when it's turning (assuming you can still hook it up to the old controller...)


Offline ROVERTopic starter

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Re: wiring help
« Reply #4 on: December 09, 2012, 11:26:30 AM »
i reinstalled the old controller and measured the voltage for the steering motor, it reads 9.7 to 9.9 volts when turned fully to the left or to the right, ive attached an image of the steering motor and its basically a dc motor with lots of gear to produce a lot of torque from a very small dc motor, should it be alright to hook it up on one of the outputs of the motor controller?




Offline Soeren

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Re: wiring help
« Reply #5 on: December 09, 2012, 07:06:07 PM »
Hi,

[...] should it be alright to hook it up on one of the outputs of the motor controller?
If you give it the right voltage, yes.
Most "cheap" ready built R/C cars have got a DC motor  for steering and mostly without feedback, so it's hard left/right or center.

The black wire on the other motor is likely a ground lead (although it's skimpy), as a motor mounted in a plastic chassis has got no other way to ground the motor housing. Measure the resistance between the black wires far end and the motor housing itself and you'll know for sure.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


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