Instead of having to wire my battery pack supply pins into Vin, I can plug them directly into the Arduino's power adapter. I soldered a barrel jack onto the 9-volt battery adapter and covered the connection in heat-shrink tubing to prevent any mishaps. Not only is it easier to connect to the Arduino, but it keeps everything a lot more clean.
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| 8 x 1.2V Rayovac 4.0 NiMH Batteries |
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| This is what happens when you order more stuff, bigger box for projects. |
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| Plastic geared motors with matching sumo wheels |
Since the robot will be driven by two wheels, I'll need a caster to help keep it balanced. Replaced the guitar pick with an actual metal caster ball.
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| http://www.sparkfun.com/products/8909 |
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| You can sort of see the motor driver in there. I need to get another spool of wire to make longer jumpers |
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| No the arduino isn't going to hang out of the box, it's just for show! |
Enough talk, let's see it in action:
The digital camera can record sound, unlike my cellphone.
Made a quick change to the code and didn't want to re-record the first video!
Here is the code from the demo video:
Once again, this code is made specifically for the 1A Dual TB6612FNG motor driver.
// Noah Stahl
// 8/25/2011
// http://arduinomega.blogspot.com
// Arduino Mega 2560
//This sketch is used to control the TB6612FNG Motor Driver.
//The Motor Driver is controlling two bidirectional DC Motors, A and B.
//There are four states for each motor in this code: STANDBY, BRAKE, CW, CCW.
//The speed of the motors can be controlled through PWM. 0 for stopped and
//255 for full-speed.
//!!!READ-ME!!!
//Depending on the placement and wiring of your motors, this code may not work
//as intended on your project. YMMV! You can fix any of the wrong directions by
//changing the FORWARD, REVERSE, RIGHT, and LEFT define values below.
//You will also have to do a little experimenting to determine a good delay
//value for turning. This value is going to change depending on your motor speed,
//torque, surface material, battery voltage, and a whole bunch of other variables
//that you will probably be unable to account for. Just use a good guess.
// LCD Vss(1) to GND
// LCD Vdd(2) to +5V
// LCD Vo (3) to +5V (contrast control)
// LCD RS (4) to digital pin 43
// LCD R/W(5) to GND
// LCD EN (6) to digital pin 42
// LCD D4 (7) to digital pin 40
// LCD D5 (8) to digital pin 39
// LCD D6 (9) to digital pin 38
// LCD D7 (10)to digital pin 37
#include <LiquidCrystal.h>
// Specify the numbers of the LCD pins on the Arduino
LiquidCrystal lcd(43, 42, 40, 39, 38, 37); // RS, EN, D4, D5, D6, D7
#define PWMA 2
#define AIN1 53
#define AIN2 52
#define BIN1 51
#define BIN2 50
#define PWMB 3
#define STBY 49
#define motor_A 0
#define motor_B 1
#define FORWARD 1
#define REVERSE 0
#define RIGHT 1
#define LEFT 0
void setup()
{
pinMode(PWMA,OUTPUT);
pinMode(AIN1,OUTPUT);
pinMode(AIN2,OUTPUT);
pinMode(PWMB,OUTPUT);
pinMode(BIN1,OUTPUT);
pinMode(BIN2,OUTPUT);
pinMode(STBY,OUTPUT);
lcd.begin(20, 2); // Number of columns and rows on the LCD
lcd.println("ArduinoMega Blagspot");
lcd.setCursor(0,1);
lcd.println(" Motor Driver ");
delay(5000);
lcd.clear();
motor_standby(false); //Must set STBY pin to HIGH in order to move
}
void loop()
{
motor_brake(); //STOP for 1s
delay(1000);
motor_drive(FORWARD, 255); //Move FORWARD at full speed for 1s
delay(1000);
motor_brake(); //STOP for 1s
delay(1000);
motor_drive(REVERSE, 150); //REVERSE at about half-speed for 1s
delay(1000);
motor_brake(); //STOP for 1s
delay(1000);
motor_turn(RIGHT, 255, 255); //Spin RIGHT for 0.5s
delay(500);
}
//Turns off the outputs of the Motor Driver when true
void motor_standby(char standby)
{
if (standby == true) digitalWrite(STBY,LOW);
else digitalWrite(STBY,HIGH);
lcd.clear();
lcd.setCursor(0,0);
lcd.print("MOTOR ON");
}
//Stops the motors from spinning and locks the wheels
void motor_brake()
{
digitalWrite(AIN1,1);
digitalWrite(AIN2,1);
digitalWrite(PWMA,LOW);
digitalWrite(BIN1,1);
digitalWrite(BIN2,1);
digitalWrite(PWMB,LOW);
lcd.clear();
lcd.setCursor(0,0);
lcd.print("STOP");
}
//Control the direction the motors turn, speed from 0(off) to 255(full speed)
void motor_drive(char direction, unsigned char speed)
{
if (direction == FORWARD)
{
motor_control(motor_A, FORWARD, speed);
motor_control(motor_B, FORWARD, speed);
lcd.clear();
lcd.setCursor(0,0);
lcd.print("FORWARD");
lcd.setCursor(0,1);
lcd.print("Speed: ");
lcd.print((int)speed);
}
else
{
motor_control(motor_A, REVERSE, speed);
motor_control(motor_B, REVERSE, speed);
lcd.clear();
lcd.setCursor(0,0);
lcd.print("REVERSE");
lcd.setCursor(0,1);
lcd.print("Speed: ");
lcd.print((int)speed);
}
}
//You can control the turn radius by specifying the speed of each motor
//Set both to 255 for it to spin in place
void motor_turn(char direction, unsigned char speed_A, unsigned char speed_B )
{
if (direction == RIGHT)
{
motor_control(motor_A, REVERSE, speed_A);
motor_control(motor_B, FORWARD, speed_B);
lcd.clear();
lcd.setCursor(0,0);
lcd.print("RIGHT");
lcd.setCursor(0,1);
lcd.print("Speed: ");
lcd.print((int)speed_A);
}
else
{
motor_control(motor_A, FORWARD, speed_A);
motor_control(motor_B, REVERSE, speed_B);
lcd.clear();
lcd.setCursor(0,0);
lcd.print("LEFT");
lcd.setCursor(0,1);
lcd.print("Speed: ");
lcd.print((int)speed_A);
}
}
void motor_control(char motor, char direction, unsigned char speed)
{
if (motor == motor_A)
{
if (direction == FORWARD)
{
digitalWrite(AIN1,HIGH);
digitalWrite(AIN2,LOW);
}
else
{
digitalWrite(AIN1,LOW);
digitalWrite(AIN2,HIGH);
}
analogWrite(PWMA,speed);
}
else
{
if (direction == FORWARD) //Notice how the direction is reversed for motor_B
{ //This is because they are placed on opposite sides
digitalWrite(BIN1,LOW); //To go FORWARD, motor_A spins CW and motor_B spins CCW
digitalWrite(BIN2,HIGH);
}
else
{
digitalWrite(BIN1,HIGH);
digitalWrite(BIN2,LOW);
}
analogWrite(PWMB,speed);
}
}
When it comes time to build my robot, I am most likely going to need to upgrade my plastic motors to metal gearmotors. I'd hate to have the plastic gears fail in the middle of a demonstration. As long as I can keep the current for each motor under 1.2A continuous and 3A peak, I will be able to still use this motor driver and the code.
