Help in choosing the correct servo

I need help in choosing a servo controller for my robot. I am using 4 pololu brushed motors, and two pololu 18V15 motor controllers, I built a tank style robot. Two left side wheels controlled by one motor controller, and two right side wheels controlled by the other motor controller.

I am using an arduino mega attached to an Xbee series 1 to receive data from the transmitter and writing this data via TTL to the arduino to the motor controllers. The transmitter is made up of two joy sticks attached to the transmitting xbee. After much trial and error it actually works!!

Phase two is to make an arm with two servos. One to raise it an the other to extend it even higher. Also I would like to make a pan/tilt camera attached to the end of the arm.

This makes 4 joy sticks (one for pan/tilt, one for the arm, and two for the tank control(left and right side), 4 servos, plus 2 motor drivers.

  1. I am assuming the arduino Mega can’t handle all that and I need a seperate servo controller with another arduino?

  2. Am I on the right track with this setup?

  3. Which Pololu servo controller should I use if this is possible.

I would like to stay with the xbee’s as I am learning this, but eventually will graduate to RC control.

Thank you for your time,

It does sound like you are on the right track jedihonor.

Your assumption that the Mega can’t do all of that is faulty though. If you are controlling the motor drivers via RC pulse, then even an Uno can do all of that and more! If you are controlling the driver via serial, then you should use the hardware serial ports on the mega, or you may have to program more carefully using SoftwareSerial.

The capabilities of microcontrollers are far greater than many people assume. The real issue is good programming practices. One of the checks is that if you are using long delay()'s a lot, you probably need to re-evaluate your program flow. Use millis() and micros() and divide the work into functions.

Check out the Arduino Servo library if you haven’t already.

The XBees are actually really great for RC control. “Upgrading” will probably be unnecessary unless you are having interference issues with other RC pilots/drivers. On the other hand, the transmitters that come with RC equipment are really nice.

As Darth Maker said, the Arduino Mega might be able to handle all of that. In general, controlling servos well can be a burden to the processor. If you would like to offload that burden, you might consider using one of our Maestro servo controllers, which can be controlled by your Mega over the serial interface.


Thank you Darth Maker and Derrill.
After a few hours, I got it working. My tank style 4 wheel robot, two motor controllers, and the two servos pan/tilt, using the Arduino Mega, and Xbee series 1. Can’t believe it works although it looks a mess. I have ordered the maestro servo mini 12 to see if I can actually now put together the arm that goes up and down.

I want to press a button, and have the arm extend at a set speed and stop at full extension, and another button to retract, all the while using the pan/tilt while the robot is moving.
Thanks for helping,