ploeffler / dcmotorservo

Arduino Library for controlling DC motors with rotary encoders.

DCMotorServo

An Arduino Library for controlling DC motors with rotary encoders. This library uses PID and Encoder feedback. It is modeled a little bit after the AccelStepper library.

• Encoder Library, for measuring quadrature encoded signals from http://www.pjrc.com/teensy/td_libs_Encoder.html
• PID Library, for using encoder feedback to controll the motor from http://playground.arduino.cc/Code/PIDLibrary also on GitHub

Circuit

I used a 754410 quad half-H controller (a pin-compatible L293D). I'm sure it would be cheaper to make out of other components, but i've never done transistor matching, and i'm afraid of burning things.

Example circuit connections

L293D or 754410 pins	Device
1, 9	arduino	pin_pwm_output
2, 15	arduino	pin_dir
7, 10	arduino	pin_dir
4, 5, 12, 13	power	GND
16	power	5V
8	power	12V
3, 14	motor	motor pin 1
6, 11	motor	motor pin 2

Hardware

• Metal Gearmotor 37Dx57L mm with 64 CPR Encoder from Pololu
• Arduino
• 754410 or L293D MC33926 Motor Driver Carrier

Pins

Pinout for motor control uses 3 pins for output. It is somewhat wasteful, but had more flexibility. Two pins for direction control, and one for motor power (assuming PWM). Be sure to pick a PWM capable pin for pin_pwm_output.

The two input pins are for the encoder feedback.

Two direcional pins allow for setting a motor brake by shorting the terminals of the motor together (set both directions HIGH, and preferably turn off the PWM)

TODO

• implement brake feature for 3-pin mode
• 2-pin constructor
• implement friendlier tuning method for PID