I have a project dealing with 3 servos (12v 5a max) and was wondering if I had a motor controller, with an external power supply, hooked up to each servo, can I connect all 3 motor controllers to 1 uno?
You don't use motor controllers with servos - look in the playground.
Dietz4345: 3 servos (12v 5a max)
Those don't sound like the sort of RC hobby servos that we usually associated with the word servo. What are the electrical characteristics of these servos - how are they controlled, how are they powered?
Yes, point to some datasheet for these motors you have. We have no idea what you are working with.
Yeah sorry it's a pololu dc brushed gear motor.
Pololu 12V, 100:1 Gear Motor w/Encoder
• Gear ratio: 100:1 • Free-run speed @ 12V: 100 rpm • Free-run current @ 12V: 300 mA • Stall current @ 12V: 5000 mA • Stall torque @ 12V: 220 oz·in
The stall current is high enough to rule out the common Arduino-specific motor driver shields, but you can probably find a motor driver board which supports that voltage and current. Once you have selected the driver board you can look at the spec to see how many pins each motor is going to need.
If you don't need variable speed control then you could get away with a relay instead of a motor driver, and if you don't need it to be reversible that makes things even simpler.
I saw that the arduino motor controller can supply 4amps to the motor. The motor can still run on 4amps, we are willing to take the decrease in power.