I am currently using the attached 2DW Robot Chassis. 2 geared DC motors are used. I am controlling the motors with an Arduino Leonardo and a motor driver that is essentially identical to Adafruit's Motor Driver v2.0. The issue is that when I supply power to the Arduino via either the USB cable (attached to my laptop) or via the power jack (with a 12V DC supply), the motors do what my code tells them to do. However, when I supply power to the motor shield via the power terminals using either 5, 6, or 8 AA batteries, the motors seem to just do whatever they want. They start by jerking around a little, then run continuously until I disconnect a battery. I have the VIN jumper attached to the shield, and the Arduino power LED says that it is on; it just doesn't seem to be transferring the proper instructions, but it does when I power the Arduino and not the shield. In all cases, the power LED on the shield is on.
I have seen several sources saying it is unwise to power the Arduino and the motors using the same power source, but what other option is there for a mobile robot?
My code:
#include <Wire.h>
#include <Adafruit_MotorShield.h>
#include "utility/Adafruit_MS_PWMServoDriver.h"
Adafruit_MotorShield AFMS = Adafruit_MotorShield();
Adafruit_DCMotor *leftMotor = AFMS.getMotor(1);
Adafruit_DCMotor *rightMotor = AFMS.getMotor(2);
void setup() {
AFMS.begin();
}
void stopMotors() {
leftMotor -> setSpeed(0);
rightMotor -> setSpeed(0);
leftMotor -> run(RELEASE);
rightMotor -> run(RELEASE);
}
void loop() {
// both motors run at 50% speed for 2 seconds
leftMotor -> setSpeed(128);
leftMotor -> run(FORWARD);
rightMotor -> setSpeed(128);
rightMotor -> run(FORWARD);
delay(2000);
stopMotors();
delay(1000);
// left turn for 1 second
leftMotor -> run(BACKWARD);
rightMotor -> run(FORWARD);
leftMotor -> setSpeed(128);
rightMotor -> setSpeed(128);
delay(1000);
stopMotors();
delay(1000);
// forward again
leftMotor -> setSpeed(128);
leftMotor -> run(FORWARD);
rightMotor -> setSpeed(128);
rightMotor -> run(FORWARD);
delay(2000);
stopMotors();
delay(1000);
// rotate right at 25% speed
leftMotor -> run(FORWARD);
rightMotor -> run(BACKWARD);
leftMotor -> setSpeed(64);
rightMotor -> setSpeed(64);
delay(2000);
stopMotors();
delay(1000);
}
