Arduino drawing too much current?

Hello everyone, we're trying to make a robot rotate a weighted flat board 180degrees on top of a chassis.

After a few attempts of it working, suddenly the board was only turning just over 90degrees, and then resetting and starting from the beginning of It's program. A nearby classmate told us that "the Arduino had drawn too much current and stopped working". It is powered by 9 AA batteries. We know this particular board is "Arduino Duemilanove or Nano w/ ATmega328".

Does anyone here know what we can do to fix this?

Thanks -Josh, Dan & Fizi

You need to measure your 9 volt supply from the AAs to ensure they are giving adequate voltage output. It is possible that your earlier trials have drain the cells. If both arduino and motor are powered from the same 9 volt supply, it's unlikely that the arduino is drawing excess current, more like the servo (or whatever) that's doing the rotation.

JOBrien: Does anyone here know what we can do to fix this?

Are you certain that you have identified the problem correctly ?

Does the same happen if you run the Arduino from a seperate power supply ?

Like the old saying : don't try to fix something that isn't broken.

Just a thought.

JOBrien: Hello everyone, we're trying to make a robot rotate a weighted flat board 180degrees on top of a chassis.

After a few attempts of it working, suddenly the board was only turning just over 90degrees, and then resetting and starting from the beginning of It's program. A nearby classmate told us that "the Arduino had drawn too much current and stopped working". It is powered by 9 AA batteries. We know this particular board is "Arduino Duemilanove or Nano w/ ATmega328".

Does anyone here know what we can do to fix this?

Thanks -Josh, Dan & Fizi

  1. What is rotating the board? A servo? A gear-motor?
  2. What is driving the motor (if it is a gear-motor)? What kind of motor controller is used?
  3. 9 AA batteries - in series? That's 13.5 volts (if using alkaline, if using 1.2 V cells, then its 10.8 volts, of course) - are you driving both the servo (or motor), and the Arduino off both at the same time?
  4. If you are driving a servo (vs a gearmotor) using anything more than 6 volts or so - you are at risk of burning out the servo.

You want to fix this?

  1. First off, measure the stall current needs of the servo or gear motor you are using to turn the table. This will give your upper limit on what you need for your power supply.
  2. If you are using servos, find out their max voltage requirements - DO NOT EXCEED THIS.
  3. Use separate supplies for the Arduino and the servos (but tie thier grounds together). You should not be driving the Arduino with anything more than 9 VDC - you can go up to around 12 VDC with the on-board regulator, but it will get really hot (it really needs a heat sink). Keep it around 7-9 volts to keep the heat down.

If you are using a servo to turn the board, then use 4 or 5 C cells in series for the servo power supply, and 6 AA cells in series for the Arduino. If you are using a gear motor, it will depend on the size of the motor, but if it is a small gear motor with a small 6V hobbyist motor in it, 4 to 5 C cells would still be ok.

  1. What is rotating the board? A servo? A gear-motor? A gear motor controls a wheel that rolls around in a circle on the board below. We have not used any servos

  2. What is driving the motor (if it is a gear-motor)? What kind of motor controller is used? The Arduino controlls whether or not the motor receives power from the batteries.

  3. 9 AA batteries - in series? That's 13.5 volts (if using alkaline, if using 1.2 V cells, then its 10.8 volts, of course) - are you driving both the servo (or motor), and the Arduino off both at the same time? I apologise for this, it is 6 AA batteries, and i believe it is powering both the Arduino and the motor.

Thanks

A nearby classmate told us that "the Arduino had drawn too much current and stopped working"

Then that class mate is either a fool or very sloppy at talking. You can kill an arduino if you draw too much current from it but not the other way round.