Could you expand on that? 40ma is over the threshold that the Arduino can supply safely using the on-board power?
Out of curiosity, what's a good way of knowing how many mA a piece of hardware is going to pull?
I'm assuming smeezekitty's assumption that the motor would be more than 40mA was based upon some pre-existing knowledge--but is there a basic cheat sheet or rule of thumb?
Does the motor shield make this sort of simple interaction (Arduino to pager motor) easier? From what I can tell from the FAQ it's designed more for larger 6v+ motors.
I noticed the specs have "4 H-Bridges: L293D chipset provides 0.6A per bridge (1.2A peak) with thermal shutdown protection, internal kickback protection diodes. Can run motors on 4.5VDC to 36VDC."
Unfortunately, this bridge likely won't work with your motor, as you motor is likely a 1.5-3.0 VDC motor; while you could "overvolt" the motor with 4.5-5.0 VDC, its bearings and other parts will likely fail in short order, leaving you with a burned out motor.
What is the data sheet voltage drop across that h-bridge? If it is 1-2v then the motor might be ok. A diode in series on the power supply could provide another .7v drop.
Though as Danrosey points out, he's only playing around, so if the shield interests him and he thinks he could use it for something else in the future (which I'm sure he could!), maybe he should go for it!
How can the output voltage be greater then the input voltage?
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