Blog 19

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Revision as of 11:21, 23 November 2015 by Cartridge1987 (talk | contribs) (2 Wheeled car: Arduino Version)

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2 Wheeled car: Arduino Version

#define Motor 0x48

#include <Wire.h> 

//Time to pause rotating
//static unsigned long Pause = 10000;
static unsigned long Speed = 40;

void setup()
  Wire.begin(); // wake up I2C bus

byte get_var(byte address, byte reg)
  byte value;   
  delayMicroseconds (10);
  Wire.requestFrom(Motor, 1);
  value =;
  return value;

void set_var(byte address, byte reg, byte value)
  Wire.beginTransmission(address); // transmit to motor     
  delayMicroseconds  (10);
  delayMicroseconds  (10);
  Wire.endTransmission();    // stop transmitting

void loop()
  unsigned long AddressA;
  unsigned long AddressB;  

  char buf[32];
  set_var(0x48, 0x21, Speed); 
  set_var(0x48, 0x31, Speed);  

  AddressA = get_var(0x48, 0x21);
  sprintf (buf, "Speed:  A:%d ", AddressA);
  Serial.write (buf); 

  AddressB = get_var(0x48, 0x31);
  sprintf (buf, " B:  %d\r\n", AddressB);
  Serial.write (buf); 

//  delay(Pause);

This is the list I have made for the Raspberry Pi Version, what also counts for the Arduino version(If your car is switched to the other side this can of course be the opposite):

  • # X is forwards - Y is backwards
  • #Wheels at front
  • #20 A backwards
  • #21 A forwards
  • #22 A stop
  • #30 B backwards
  • #31 B forwards
  • #32 B stop

You can also check the motor protocol, for more info.

In my example script we go forward with 0x21 + 0x31 having the same value. For other movements you should have(If you car is flipped this can of course be the opposite!):

To go backwards:

  set_var(0x48, 0x20, Same Speed value); 
  set_var(0x48, 0x30, Same Speed value); 

To go left:

  set_var(0x48, 0x21, High Speed value); 
  set_var(0x48, 0x31, Low Speed value); 

To go right:

  set_var(0x48, 0x21, Low Speed value); 
  set_var(0x48, 0x31, High Speed value); 

To stop the car:

  set_var(0x48, 0x21, Speed value doesn't matter); 
  set_var(0x48, 0x31, Speed value doesn't matter);

To rotate to the left:

  set_var(0x48, 0x21, Same Speed value); 
  set_var(0x48, 0x30, Same Speed value); 

To rotate to the right:

  set_var(0x48, 0x20, Same Speed value); 
  set_var(0x48, 0x31, Same Speed value);

If you do this don't forget to add: static unsigned long Speed2 = "Put here your value";