Let's Make Robots!

how is this possible without an hbridge or similar?


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ezee's picture

i made the incorrect that servos and motors operated similarly....now I understand, thanks.

OddBot's picture

Servos do contain a "H" bridge as well as other control circuitry.

The control wire from the servo just requires a low power, digital signal. Servos can be powered from your processors +5V rail but it is not normally a good idea as a servo can draw a fair bit of current under heavy load.

Ideally your servos should be powered directly from your battery. If you use a seperate battery for the servos, make sure to connect the grounds otherwise your control signal will not have a return path.

birdmun's picture

As long as the servo doesn't pull more current than the powersupply/voltage regulator/battery pack can supply, you won't have any problems driving a servo directly from pretty any* microcontroller.

*NOTE: I say any with a note, because, I don't know of any micro that would have a problem driving a servo directly. Just because I don't know of one, doesn't mean there isn't one out there that can not drive a servo directly. It probably would not be very useful to robotics.

Maxhirez's picture
Just 3.6 g servos directly out of the Arduino. It's pretty clearly not able to steer using the wings. It maintains its vector once they begin to flap.