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Topic: Can I drive tiny steppers with digital pin directly? (Read 3172 times) previous topic - next topic

MorganS

20mA is "a lot". That's its normal operating load, within the specifications.

40mA is "OMG it might die!" It almost certainly won't, but that's only an "almost".
"The problem is in the code you didn't post."

ma_hty

http://www.ebay.com/itm/2pcs-DC-5V-Stepper-Motor-28BYJ-48-ULN2003-Driver-Test-Module-Board-for-Arduino-/321779670958


How about the stepper motor above?

5V and Phase Resistance 200Ω.

Phase Resistance 200Ω + Pin Output Resistance 30Ω, that will give us 230Ω.  Running at 5V, the current would be about 22 mA.  By the way, this one can only be unipolar, so current sinking at output pins is not needed.

( I'm really just curious.  Even if I can really drive a stepper motor with digital pins directly, I unlikely will do it as using a stepper motor drivers is simpler. )

MorganS

That doesn't seem entirely correct. That's either a mistake in the specifications or a really weak stepper motor. It could be fun to try though.
"The problem is in the code you didn't post."

ma_hty

That doesn't seem entirely correct. That's either a mistake in the specifications or a really weak stepper motor. It could be fun to try though.
^^" I played with this one a while ago.  It indeed is a weak stepper motor, not much torque even after gearing down by 64 times.  It's probably just intended for some casual projects.

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