Instructables

RC servo Torque Increase?

Hi;
I have a DC Servo motor. I want to increase its torque. It has 12volt and max 900mamp current gives 15kgcm torque. I want to remove the tiny DC motor and fix a 5amp 12volt big motor with metal gears. I want to ask " How can I give more current without burning the main SMD circuit board". If I place a battery in parallel to the motor terminals it can burn the circuit. Any ideas ?

If you are changing the motor to a much larger one then whatever motor drive electronics that are currently in the servo won't be adequate. There won't really be much of the original servo left that can be used, except may be the potentiometer that provides the feedback of the position.

I think I have seen modules at places like Pololu and other sites that cater to hobby robotics that are intended for use in making a servo out of a larger gear motor. I would look into something like that.
MohitJindal (author)  LargeMouthBass1 year ago
I am planning to buy a new DC motor driver board which can run 5amp motor but I don't know how to connect it with Atmega 8A chip. Please see the pdf I attached for Atmega 8A.

Here are the 7 pins in DC motor controller:-

Pin No. Pin Functionality
1 GND Ground
2 IN-1 Logic input for the motor direction.
3 Diagnostic 1
(DG-1) Output pin with logic 1 output in normal operation. Represents side of the internal
H bridge corresponding to IN-1. Pin is pulled to logic low by the motor driver in
case of over temperature or overload due to short circuit.
4 PWM Used to apply Pulse Width Modulation to control motor velocity
5 Diagnostic 2
(DG-2) Output pin with logic 1 output in normal operation. Represents side of the internal
H bridge corresponding to IN-2. Pin is pulled to logic low by the motor driver in
case of over temperature or overload due to short circuit.
6 IN-2 Logic input for the motor direction.
7 CS* Current Sense output to measure the current flowing through the driver
Your motor controller looks to be a dual driver, and it expects to see a direction signal and a PWM signal for speed control from your processor. The CS output would only need to be used if you wanted to know the motor current, and the diagostic pins would only need to be connected if you want your micro to detect a fault on the motor controller.