Powering 28byj-48 5v stepper motor through arduino

[thano]

I'm still learning about electronics so please excuse me if I say something extremely stupid.

I was looking at how to use a 28byj-48 5V stepper motor, and every website I read warned me never to try powering it through the 5v pin on the arduino. But when I checked I read that apparently it draws 250mA of current, and all sources told me that the 5v pin could handle that and much more. I just wanted to ask what the problem was in that case, because it left me confused.

[LarryD]

• Pulling 1/4 Amp from the Arduino 5V pin can damage components on your Arduino leaving it unusable.

[jim-p]

@thano

and all sources told me that the 5v pin could handle that and much more.

That is true, actually it can supply up to 800mA
However what the "all sources" didn't tell you is that it can only supply that much current for a few seconds before the regulator burns up

[groundFungus]

For experiments only, I power one of those small steppers from the Arduino. It is the only thing powered by the Arduino and the power is actually coming from USB.

For any serious or permanent project the motor would get its own power supply. So in the case of a tutorial, you may run from the Arduino, but it should be made clear that that is not great practice.

[LarryD]

@groundFungus

For experiments only, I power one of those small steppers from the Arduino.

Hand slap !
_{I do to}

[DaveX]

@groundFungus

For experiments only, I power one of those small steppers from the Arduino. It is the only thing powered by the Arduino and the power is actually coming from USB.

...through the Uno R3's 500ma polyfuse:

...as on the Mega:

Mega with 1 ohm across VIN and 5v

Does it have a polyfuse ? The polyfuse triggers at 500mA. [afbeelding]

[groundFungus]

I am not saying that its right nor am i proud of it but short term powering from Arduino (really USB) has caused no blue smoke.

I have tripped the polyfuse, but not with a little stepper.