Overflow enthusiasts!

I am trying to build a balancing robot with two wheels, using the polulu gear motor as mentioned above. In order to have a strong motor driver,the monster moto shield is used in this project. Here is the components and datasheets which is used.


Lipo batteries Arduino saint smart 2x Pololu 12V, 29:1 Gear Motor w/Encoder Monster moto shield

Now, back to the issue.. Well, the first problem I encountered was my motor driver. It keeps getting hot after a while, whenever I use it ( I run 2 motors through 1 driver). And the most frustrating part is that the motors can stop for a while, and then restart again ( suspect a hardware reset here). Is there any way this can be solved?, I have checked the datasheet for the monster moto driver but can't understand whether the components are already on the PCB boad or I manually have to add new components like resistors, capacitors and etc. Would be glad if you guys directed me on this issue.

Secondly, The other problem I have is that the motors are going fast CW and slow CCW whenever I reverse direction. I have also seen other ppl getting the same problem as I do and wonder why this happen.

Should I add external components ? Then which components should I use in order to subdue this problem?

Here are some pictures in order to clarify the problem. Mostly using cables to connect inputs and etc. I would be glad if you wonder something and want me to post more information.


enter image description here

enter image description here


/*  MonsterMoto Shield Example Sketch
  date: 5/24/11
  code by: Jim Lindblom
  hardware by: Nate Bernstein[![enter image description here][1]][1]
  SparkFun Electronics
 This is really simple example code to get you some basic
 functionality with the MonsterMoto Shield. The MonsterMote uses
 two VNH2SP30 high-current full-bridge motor drivers.

 Use the motorGo(uint8_t motor, uint8_t direct, uint8_t pwm) 
 function to get motors going in either CW, CCW, BRAKE[![enter image description here][1]][1]VCC, or 
 BRAKEGND. Use motorOff(int motor) to turn a specific motor off.

 The motor variable in each function should be either a 0 or a 1.
 pwm in the motorGo function should be a value between 0 and 255.

This code is beerware; if you see me (or any other SparkFun employee) at the
local, and you've found our code helpful, please buy us a round!
Distributed as-is; no warranty is given.
#define BRAKEVCC 0
#define CW   1
#define CCW  2
#define BRAKEGND 3
#define CS_THRESHOLD 100

/*  VNH2SP30 pin definitions
 xxx[0] controls '1' outputs
 xxx[1] controls '2' outputs */
int inApin[2] = {7, 4};  // INA: Clockwise input
int inBpin[2] = {8, 9}; // INB: Counter-clockwise input
int pwmpin[2] = {5, 6}; // PWM input
int cspin[2] = {2, 3}; // CS: Current sense ANALOG input
int enpin[2] = {0, 1}; // EN: Status of switches output (Analog pin)

int statpin = 13;

void setup()

  pinMode(statpin, OUTPUT);

  // Initialize digital pins as outputs
  for (int i=0; i<2; i++)
    pinMode(inApin[i], OUTPUT);
    pinMode(inBpin[i], OUTPUT);
    pinMode(pwmpin[i], OUTPUT);
  // Initialize braked
  for (int i=0; i<2; i++)
    digitalWrite(inApin[i], LOW);
    digitalWrite(inBpin[i], LOW);
  // motorGo(0, CW, 1022e3);
  // motorGo(1, CCW, 1023);

void loop()
  motorGo(0, CW, 1023);
  motorGo(1, CW, 1023);
  motorGo(0, CCW, 1023);
  motorGo(1, CCW, 1023);
  if ((analogRead(cspin[0]) < CS_THRESHOLD) && (analogRead(cspin[1]) < CS_THRESHOLD))
    digitalWrite(statpin, HIGH);

void motorOff(int motor)
  // Initialize braked
  for (int i=0; i<2; i++)
    digitalWrite(inApin[i], LOW);
    digitalWrite(inBpin[i], LOW);
  analogWrite(pwmpin[motor], 0);

/* motorGo() will set a motor going in a specific direction
 the motor will continue going in that direction, at that speed
 until told to do otherwise.

 motor: this should be either 0 or 1, will selet which of the two
 motors to be controlled

 direct: Should be between 0 and 3, with the following result
 0: Brake to VCC
 1: Clockwise
 2: CounterClockwise
 3: Brake to GND

 pwm: should be a value between ? and 1023, higher the number, the faster
 it'll go
void motorGo(uint8_t motor, uint8_t direct, uint8_t pwm)
  if (motor <= 1)
    if (direct <=4)
      // Set inA[motor]
      if (direct <=1)
        digitalWrite(inApin[motor], HIGH);
        digitalWrite(inApin[motor], LOW);

      // Set inB[motor]
      if ((direct==0)||(direct==2))
        digitalWrite(inBpin[motor], HIGH);
        digitalWrite(inBpin[motor], LOW);

      analogWrite(pwmpin[motor], pwm);

regards, Volkan

  • 1
    \$\begingroup\$ You didn't mention the actual battery you are using. What is the voltage and current ratings for it? Also, I doubt this is the root of your issues, but the cheap jumper wires you are using cannot reasonably handle the full 5A stall current of those motors. Secondly, it's not a good idea to drive a motor quickly in one direction and then instantly switch directions. Lastly, the Arduino code is gibberish to many EE's, so if it's a an issue with that, you might have better luck here: arduino.stackexchange.com \$\endgroup\$ – Kurt E. Clothier Jul 26 '15 at 2:28
  • \$\begingroup\$ The battery im using is a Li-poly RC Battery 2800mah 11.1V 35C. Could it be that the cables are to small to drive high current ? \$\endgroup\$ – ozzmanli Jul 26 '15 at 11:33
  • \$\begingroup\$ That battery should be fine, and the wire gauge shouldn't matter if you aren't putting this under load -that is, just driving the motors with the thing upside down like in your picture is fine... but when actually driving the robot around, you will want a better connection. I'm afraid my knowledge stops where the Arduino nonsense begins. \$\endgroup\$ – Kurt E. Clothier Jul 28 '15 at 3:10
  • \$\begingroup\$ Ok, Kurt I appreciate your time and effort to help me out. I will hopefully fix this problem . \$\endgroup\$ – ozzmanli Jul 28 '15 at 11:55
  • \$\begingroup\$ Good Luck, And Try Your question OnThe Arduino Page. \$\endgroup\$ – Kurt E. Clothier Jul 29 '15 at 15:35

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