Ardumoto

I am using ardumoto to control a dc motor,

#define PwmPinMotorA 10
#define PwmPinMotorB 11
#define DirectionPinMotorA 12
#define DirectionPinMotorB 13

void setup(){
  pinMode(PwmPinMotorA, OUTPUT);
  pinMode(PwmPinMotorB, OUTPUT);
  pinMode(DirectionPinMotorA, OUTPUT);
  pinMode(DirectionPinMotorB, OUTPUT);
}

void loop(){
  analogWrite(PwmPinMotorA, 100);
  digitalWrite(DirectionPinMotorA, LOW);
}

Using this sketch, motor is connected to output 1/2. But all i get is some hissing sound from the motor and no movement at all. Also the direction LED on the ardumoto goes dim.

Am i doing something wrong? I have tried with two different motors non work.

Try using a transistor and more power

motor is connected to output 1/2

but:- analogWrite(PwmPinMotorA, 128); Is needed for half. But that is minor.

Have you tried full? Motors often won't start off slow but can be brought down when running.

Make sure you have not confused direction with enable as this also would cause these symptoms.

It sounds like you have not got enough voltage or current capability from your supply.

Following the replies here is what i did,

i removed the digitalWrite, upped the speed now only

  analogWrite(PwmPinMotorA, 255);

remains. What i did not try was to give motor a little push, if i do that it starts spinning but without a little push it can't move, it's like the magnets are holding it..

Does that mean that the current is not enough? Using the method explaing here http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1238366770 using a multimeter i get a reading of .20, so thats 20 milli amps? am i wrong? i have 40 on the pins?

Well that means you need to give the motor more power. You should try to use a transistor like so: http://www.neufeld.newton.ks.us/images/electronics/2006/03/08/motor-demo-transistor.png

forgive my ignorance but can you explain a little more how a transistor will help me? what exactly my problem is?

/cs guy

What powersupply are you using ?

Well the problem you have is that the motor doesn't get the power it need. With the transistor you can control the motor with the arduino but the power will come from a more powerful power supply.

I think you are missing the point he is using an Ardumoto to drive the motors:- http://www.sparkfun.com/commerce/product_info.php?products_id=9213

So there is no question of a transistor being needed. You need either a power supply that will give more current, if current limiting is your problem. Or one that gives more voltage if your present PSU is not current limiting.

i have tracked the problem down to my usb hub, when i disconnected the usb hub connected directly to usb on the macbook motors started spinning.

One other question, does running on low power damage arduino? when connected through the usb hub. because i did not noticed this before with sensors before.

does running on low power damage arduino

No reducing the voltage will not harm it.

I am inclined to think it is more of a ground problem but anyway glad to here you have it working.

No reducing the voltage will not harm it.

I am inclined to think it is more of a ground problem but anyway glad to here you have it working.

you mean grounding problem on the usb hub or my circuit?