Function Introduction
This 2WD DIY Arduino Robotics Kit will teach you how to build a automatic obstacle - avoidance robot which is achieved on the platform of the Turtle Robot, based on ultrasonic sensor as distance measuring device,and combined with servo.
STEP 1: Assemble Robot
Refer to Instruction Manual
Precautions:
1. Instruction Manual says nothing about how to deal with motor wire. The next pictrue tells it.
2. Finished the robot chassis.Then following the connection diagram to wire the hardware.
STEP 2: Debug Motor
Download the Code
int speedPin_M1 = 5; //M1 Speed Control
int speedPin_M2 = 6; //M2 Speed Control
int directionPin_M1 = 4; //M1 Direction Control
int directionPin_M2 = 7; //M1 Direction Control
void setup(){
}
void loop(){
carAdvance(100,100);
delay(1000);
carBack(100,100);
delay(1000);
carTurnLeft(250,250);
delay(1000);
carTurnRight(250,250);
delay(1000);
}
void carStop(){ // Motor Stop
digitalWrite(speedPin_M2,0);
digitalWrite(directionPin_M1,LOW);
digitalWrite(speedPin_M1,0);
digitalWrite(directionPin_M2,LOW);
}
void carAdvance(int leftSpeed,int rightSpeed){ //Move forward
analogWrite (speedPin_M2,leftSpeed); //PWM Speed Control
digitalWrite(directionPin_M1,HIGH);
analogWrite (speedPin_M1,rightSpeed);
digitalWrite(directionPin_M2,HIGH);
}
void carBack(int leftSpeed,int rightSpeed){ //Move backward
analogWrite (speedPin_M2,leftSpeed);
digitalWrite(directionPin_M1,LOW);
analogWrite (speedPin_M1,rightSpeed);
digitalWrite(directionPin_M2,LOW);
}
void carTurnRight(int leftSpeed,int rightSpeed){ //Turn Right
analogWrite (speedPin_M2,leftSpeed);
digitalWrite(directionPin_M1,LOW);
analogWrite (speedPin_M1,rightSpeed);
digitalWrite(directionPin_M2,HIGH);
}
void carTurnLeft(int leftSpeed,int rightSpeed){ //Turn Left
analogWrite (speedPin_M2,leftSpeed);
digitalWrite(directionPin_M1,HIGH);
analogWrite (speedPin_M1,rightSpeed);
digitalWrite(directionPin_M2,LOW);
}STEP 3：Install Upper Plate
1. Prepare the Materials 
2. Fixed Ultrasonic Sensor Position
Please see the Installation Manual
3. Fixed Servo Position 
STEP4: Debug Ultrasonic Sensor and Servo
1. Hardware Connection
2. Download Code Install the library firstly. Metro libray
#include <Servo.h>
#include <Metro.h>
Metro measureDistance = Metro(50);
Metro sweepServo = Metro(20);
unsigned long actualDistance = 0;
Servo myservo; // create servo object to control a servo
int pos = 60;
int sweepFlag = 1;
int URPWM = 3; // PWM Output 0－25000US，Every 50US represent 1cm
int URTRIG= 10; // PWM trigger pin
uint8_t EnPwmCmd[4]={0x44,0x02,0xbb,0x01}; // distance measure command
void setup(){ // Serial initialization
myservo.attach(9);
Serial.begin(9600); // Sets the baud rate to 9600
SensorSetup();
}
void loop(){
if(measureDistance.check() == 1){
actualDistance = MeasureDistance();
// Serial.println(actualDistance);
// delay(100);
}
if(sweepServo.check() == 1){
servoSweep();
}
}
void SensorSetup(){
pinMode(URTRIG,OUTPUT); // A low pull on pin COMP/TRIG
digitalWrite(URTRIG,HIGH); // Set to HIGH
pinMode(URPWM, INPUT); // Sending Enable PWM mode command
for(int i=0;i<4;i++){
Serial.write(EnPwmCmd[i]);
}
}
int MeasureDistance(){ // a low pull on pin COMP/TRIG triggering a sensor reading
digitalWrite(URTRIG, LOW);
digitalWrite(URTRIG, HIGH); // reading Pin PWM will output pulses
unsigned long distance=pulseIn(URPWM,LOW);
if(distance==50000){ // the reading is invalid.
Serial.print("Invalid");
}else{
distance=distance/50; // every 50us low level stands for 1cm
}
return distance;
}
void servoSweep(){
if(sweepFlag ){
if(pos>=60 && pos<=120){
pos=pos+1; // in steps of 1 degree
myservo.write(pos); // tell servo to go to position in variable 'pos'
}
if(pos>119) sweepFlag = false; // assign the variable again
}else {
if(pos>=60 && pos<=120){
pos=pos-1;
myservo.write(pos);
}
if(pos<61) sweepFlag = true;
}
}STEP 5: Debugging Robot
#include <Servo.h>
#include <Metro.h>
Metro measureDistance = Metro(50);
Metro sweepServo = Metro(20);
int speedPin_M1 = 5; //M1 Speed Control
int speedPin_M2 = 6; //M2 Speed Control
int directionPin_M1 = 4; //M1 Direction Control
int directionPin_M2 = 7; //M1 Direction Control
unsigned long actualDistance = 0;
Servo myservo; // create servo object to control a servo
int pos = 60;
int sweepFlag = 1;
int URPWM = 3; // PWM Output 0－25000US，Every 50US represent 1cm
int URTRIG= 10; // PWM trigger pin
uint8_t EnPwmCmd[4]={0x44,0x02,0xbb,0x01}; // distance measure command
void setup(){ // Serial initialization
myservo.attach(9);
Serial.begin(9600); // Sets the baud rate to 9600
SensorSetup();
}
void loop(){
if(measureDistance.check() == 1){
actualDistance = MeasureDistance();
// Serial.println(actualDistance);
// delay(100);
}
if(sweepServo.check() == 1){
servoSweep();
}
if(actualDistance <= 30){
myservo.write(90);
if(pos>=90){
// carBack(100,100);
//// Serial.println("carBack");
// delay(100);
carTurnRight(150,150);
// Serial.println("carTurnRight");
delay(100);
}else{
// carBack(100,100);
//// Serial.println("carBack");
// delay(100);
carTurnLeft(150,150);
// Serial.println("carTurnLeft");
delay(100);
}
}else{
carAdvance(70,70);
// Serial.println("carAdvance");
delay(100);
}
// carBack(150,150);
}
void SensorSetup(){
pinMode(URTRIG,OUTPUT); // A low pull on pin COMP/TRIG
digitalWrite(URTRIG,HIGH); // Set to HIGH
pinMode(URPWM, INPUT); // Sending Enable PWM mode command
for(int i=0;i<4;i++){
Serial.write(EnPwmCmd[i]);
}
}
int MeasureDistance(){ // a low pull on pin COMP/TRIG triggering a sensor reading
digitalWrite(URTRIG, LOW);
digitalWrite(URTRIG, HIGH); // reading Pin PWM will output pulses
unsigned long distance=pulseIn(URPWM,LOW);
if(distance==50000){ // the reading is invalid.
Serial.print("Invalid");
}else{
distance=distance/50; // every 50us low level stands for 1cm
}
return distance;
}
void carStop(){ // Motor Stop
digitalWrite(speedPin_M2,0);
digitalWrite(directionPin_M1,LOW);
digitalWrite(speedPin_M1,0);
digitalWrite(directionPin_M2,LOW);
}
void carAdvance(int leftSpeed,int rightSpeed){ //Move forward
analogWrite (speedPin_M2,leftSpeed); //PWM Speed Control
digitalWrite(directionPin_M1,HIGH);
analogWrite (speedPin_M1,rightSpeed);
digitalWrite(directionPin_M2,HIGH);
}
void carBack(int leftSpeed,int rightSpeed){ //Move backward
analogWrite (speedPin_M2,leftSpeed);
digitalWrite(directionPin_M1,LOW);
analogWrite (speedPin_M1,rightSpeed);
digitalWrite(directionPin_M2,LOW);
}
void carTurnRight(int leftSpeed,int rightSpeed){ //Turn Right
analogWrite (speedPin_M2,leftSpeed);
digitalWrite(directionPin_M1,LOW);
analogWrite (speedPin_M1,rightSpeed);
digitalWrite(directionPin_M2,HIGH);
}
void carTurnLeft(int leftSpeed,int rightSpeed){ //Turn Left
analogWrite (speedPin_M2,leftSpeed);
digitalWrite(directionPin_M1,HIGH);
analogWrite (speedPin_M1,rightSpeed);
digitalWrite(directionPin_M2,LOW);
}
void servoSweep(){
if(sweepFlag){
if(pos>=60 && pos<=120){
pos=pos+1; // in steps of 1 degree
myservo.write(pos); // tell servo to go to position in variable 'pos'
}
if(pos>119) sweepFlag = false; // assign the variable again
}
else {
if(pos>=60 && pos<=120){
pos=pos-1;
myservo.write(pos);
}
if(pos<61) sweepFlag = true;
}
}Your own car was born!