Andy Kelley N1YEW wrote:
>
> Hello,
>
> I have an RC car that does not have a radio and i would like to make it into a roving robot like thing.
>
> I am stuck with this:
> how do I control a motor from a PIC using one side of the motor tied to 1/2 rail(2.5v) and either grounding or connecting Vcc to the motor.  Now is the problem:
>
> I dont know how do this and I have already destroyed a few 2n222's
>
> the motor draws 6/10 of an amp.
>
> @ 2.5 volts that is 1.5 W.
>
> I tried a fet like this
>
>  -/\/\/\/\- Gate
>
>
> Source
> __|_
> /  /  /
>
> Drain - motor - 2.5v
>
> and all it did was make the motor spin in one direction.
>
> Also i have another motor i need to drive at full 5v so i need to reverse both wires on the motor if i want to go in reverse
>
> How can i do this???
>
> Thanks
> Andy N1YEW


Andy, I am guessing you don't have a lot of experience driving
a motor with transistors etc. If you want something quick and
reliable, I think there was a person here selling a small
module that can drive two dc motors (both directions) from a PIC,
it was about $20 or $25 and very simple to connect. If they don't
reply I am sure I can search my records and find his web page.

If you really want to design the motor driver circuit yourself
I think you need to research the type of transistor you are
using and make sure it can handle *many times* the 6/10 amp
you need, when the robot hits things and also starts moving
it will draw a lot more than 600mA.
:o)
-Roman

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