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Topic: Power/ Motors (Read 914 times) previous topic - next topic

2ndattempt

Nov 28, 2012, 08:03 pm Last Edit: Nov 28, 2012, 09:21 pm by 2ndattempt Reason: 1
Hi

I have one basic question about how much voltage needs and supplies an arduino uno.

How many devices like Dc motors or Stepmotors can i hook up to an arduino uno, wich one is externally powered, without burn it?


Thanks

MarkT

You want to power such things directly from an external supply, which might or might not also power Vin (or barrel jack) on the Arduino.

What you really should not do is power any motors or servos from the Arduino 5V pin.
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2ndattempt


You want to power such things directly from an external supply, which might or might not also power Vin (or barrel jack) on the Arduino.

What you really should not do is power any motors or servos from the Arduino 5V pin.


Im sorry for my bad explanation.

I know, this pin work more like an output. I already make a project with a Dc Motor with my Arduino Uno. But now i´m going to use these Dc Motor with a Mp3 Shield from Sparkfun, and maybe with a servo too, and all of that have to response to a LDR. Because of that, im wondering if its really possible power externally the Arduino Uno with so many devices like those, or the way to make it, if its possible, without smoke it.

The last time the motor circuitry was composed of a diode, a resistor and a transistor.

Thank you very much, im a totally moron in electronics.

Chagrin

You probably won't "smoke" the Arduino, but due to the power hungry nature of the motors/servos you're most likely to cause power fluctuations that will cause the Arduino to reset or make your analog readings go nutty.

This mosfet tutorial shows how to connect external power for your motor/transistor. Assuming the external power is 5V then the servo can also take power from it; connect the red and black wires to the power source and the signal line (white or orange) stays connected to the Arduino.

There should always be a ground connection between the Arduino and any external power supply.

MarkT

Quote
im wondering if its really possible power externally the Arduino Uno with so many devices like those, or the way to make it, if its possible, without smoke it.


If the motors are externally powered then they are not being powered by the Arduino, so their can't be a problem, no power flows
between the Arduino and the motor circuit, only logic control signals + ground link them.
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