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Topic: RC-Car, H-Bridge --- Need Help (Read 1 time) previous topic - next topic

barkingbeagle

Mar 06, 2012, 12:50 pm Last Edit: Mar 06, 2012, 12:53 pm by barkingbeagle Reason: 1
Hi,

a few weeks ago I wanted to throw my old (more than ten years) RC Car away. But since I'm totally interested in arduino I wanted to give it a try.

So, fact is my motor (forward / backward direction) has to speed modes.

By direct connection to 4.8V DC (the batteries are a bit fuller: around 5 V)
It "uses"

  • in the first one: 0.6A and 4.8V

  • in the second one: 1 A and 4.5 V




I still have some L293D lying around. But I dont think they fit (with 0.6 A and peak 1.2 A, I think)


Has anyone done something similar? Is there a better way to control the direction of the motor?

THX to every helpfull answer.

DuaneB

Hi,

   If the car still works, why not use the existing components, there is a long thread here on doing this, I think it was titled 'Modding an RC car'

Duane B

rcarduino.blogspot.com
Read this
http://rcarduino.blogspot.com/2012/04/servo-problems-with-arduino-part-1.html
then watch this
http://rcarduino.blogspot.com/2012/04/servo-problems-part-2-demonstration.html

Rcarduino.blogspot.com

barkingbeagle

Hi Duane,

the big problem is that the old PCB was totally covered with some kind of resin and so it was unuseable.

So I had it connected to the L293D. The Logic Power (+5V) came from the arduino and the motorpower came from the batteries (4.8V) But I have measured only <1V  across the motor and current was 600mA.

I'm a bit confused about the voltage loss....


DuaneB

Hi,
   This is far from a definitive answer, but if the motor is running, it is also acting as a generator, generating a 'back emf' search the web for this term and it may explain why you see a smaller voltage drop than you expect.

Duane B.

rcarduino.blogspot.com
Read this
http://rcarduino.blogspot.com/2012/04/servo-problems-with-arduino-part-1.html
then watch this
http://rcarduino.blogspot.com/2012/04/servo-problems-part-2-demonstration.html

Rcarduino.blogspot.com

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