Native Bi-Directional Control for 24mAh Motor

I've got a space sensitive project and need a very little motor to be bi-directional, I understand the I/O pins can handle 40mAh at an absolute maximum (info form here). My motor draws no more than 24mAh, so it sounds like I should be fine to control the direction with 2 I/O pins .. correct?

600baud: My motor draws no more than 24mAh, so it sounds like I should be fine to control the direction with 2 I/O pins .. correct?

The Arduino pins have a max of 40*mA* - NOT 40*mAh*. If you don't know the difference don't try to drive your motors from the Arduino until you learn.

24mA is VERY little for a motor. Double and treble check your information and measure it with your multimeter.

What is the stall current for the motor? That is what could ruin the Arduino. The stall current will almost certainly arise when the motor starts and reverses.

Motors usually produce high voltage spikes that can also damage an Arduino.

Probably best not to drive the motor directly from the pins unless you can afford to replace your Arduino.

...R

Robin2: The Arduino pins have a max of 40*mA* - NOT 40*mAh*. If you don't know the difference don't try to drive your motors from the Arduino until you learn.

Sorry that was the result of bad copy/paste and me not paying enough attention to my post.

Robin2: 24mA is VERY little for a motor. Double and treble check your information and measure it with your multimeter.

Yes its a very very tiny motor, will be sure to check!

Robin2: What is the stall current for the motor? That is what could ruin the Arduino. The stall current will almost certainly arise when the motor starts and reverses.

That actually is the stall current.

Robin2: Motors usually produce high voltage spikes that can also damage an Arduino.

Probably best not to drive the motor directly from the pins unless you can afford to replace your Arduino.

I'll triple check everything and hope for the best.

Thanks for the response Robin2

600baud: I've got a space sensitive project and need a very little motor to be bi-directional, I understand the I/O pins can handle 40mAh at an absolute maximum (info form here). My motor draws no more than 24mAh, so it sounds like I should be fine to control the direction with 2 I/O pins .. correct?

Your thinking logical, wiring the small motor between two output pins would allow you forward/reverse/off control. The problem you might have is the back EMF spike that any electro-magnetic device when you go from on to off, or in your case maybe forward to reverse rotation. These spikes can be quite destructive as they can rise to X4 the applied voltage. The AVR pins do have simple internal clamping diode protection but are rated for very small currents which may or may not be enough prevention against damage from your motor. So either external clamping diode protection may be required or just run the risk. What model arduino board are you using?

retrolefty: Your thinking logical

:D

retrolefty: What model arduino board are you using?

Nano V3.1

Thanks for the input Lefty

600baud:

retrolefty: Your thinking logical

:D

retrolefty: What model arduino board are you using?

Nano V3.1

Thanks for the input Lefty

Nano 3.1 boards are amoung of my favorites, I own two of them presently. So simple to just embed them into a project board.

Good luck you your project.

Reversing current is twice stall current(*), so you may have to take that into account.

Any system where the mechanical side of things can drive the motor also risks exceeding nominal stall current (and can drive the motor voltage above nominal).

(*) because then supply voltage and back-EMF sum to twice the supply voltage briefly. Ramping up and down the speed via PWM can avoid this situation.

MarkT: Reversing current is twice stall current(*), so you may have to take that into account.

wowzers! I didn't know that, thankyou MarkT