Published March 4, 2018 © GPL3+

What Do I Build Next?...A CircuitPlaygroundExpressRobot

I just received my ADABOX006 kit now to use the Circuit Express to control DC Motors in a Robot Platform

IntermediateFull instructions provided8 hours1,612

What Do I Build Next?...A CircuitPlaygroundExpressRobot

Things used in this project

Hardware components

Adafruit Circuit Playground Express

From My ADABOX006 kit

DC motor (generic)

Possibly using 4 DC Motors

L9110S Motor Controller

https://www.bananarobotics.com/shop/How-to-use-the-HG7881-(L9110)-Dual-Channel-Motor-Driver-Module (for additional info) any DC Motor Controller can be used

Adafruit 3.7v Li Ion Battery

This will be used for the Circuit Playground Express

Adafruit 8 x AA Battery Pack

This will be used for DC Motors

Dagu 4WD chassis

Any generic 2WD/4WD chassis will do, preferably with 2 Decks

Adafruit AdaBox subscription

Ultrasonic Sensor - HC-SR04 (Generic)

Servos (Tower Pro MG996R)

generic Ultrasonic sensor mount

Can be found on Amazon, DX.com, etc

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

philips screwdriver

Miscellaneous common hand tools, small adjustable wrench, plyers, screwdrivers, wire strippers, solder and soldering iron, heatshrink

Story

Well, it's been a couple of weeks since my ADABOX006 kit arrived. I was busy with the latest IOT Virtual Bootcamp, Dec. 12-14th, 2017, sponsored by ADAFRUIT, Microsoft/Azure Services, Hackster IO and the Raspberry Pi Foundation. This was again an interesting 3 days....16 hour days actually and thankfully I had taken the week off from my day job (but actually had to supply phone support for some issues). It has been three months since I started this build...too many distractions..

Back to this build. The ADABOX006 had featured the Circuit Playground Express board that I had not played with or had done coding for before. I had watched a few videos last summer when the board 1st was released. Lady ADA incorporated, many sensors and features to learn and explore but those would not be part of this initial build.

Basically, I would be using the Circuit Playground Express, a L9110 motor controller, 2 or 4 DC motors (depending upon which platform i use.... those of you who are followers know I have alot of hardware to pick from and I never like to take apart a robot) and a generic Robot base/platform. Possibly adding an Ultrasonic sensor and a servo to make it autonomous.

My Initial decoder table

I will reuse previous Arduino code from other builds (and by other authors) to test subassemblies as I build it up.

1 / 11 • ADABOX006

Along the way, things didn't work...cheap yellow motors...decided to use a 2 wheeled vs a 4 wheeled platform. I wanted to incorporate LM393 speed sensors but the CPE was short one input pad. I used an UNO to do preliminary testing of code (I don't know why...it was there) and final code would be run on the CPE once the build was complete. Space and layout and features and code snippets were changing causing further delays.

1 / 6 • Testing the 5v/3.3v regulator outputs

My daytime real job drew excessive time from my project time....

But I made progress...

1 / 4 • CPR Robot taking shape

From the above "taking shape" assembly, I began testing code snippets...

Code:

#include <Servo.h> //Servo motor library. This is standard library

#include <NewPing.h> //Ultrasonic sensor function library. You must install this library

//#include <Ultrasonic.h>

//our L298N L9110 control pins

//const int LeftMotorForward = 10; //A3 5

//const int LeftMotorBackward = 9; //A2 6

//const int RightMotorForward = 6; //A1 11

//const int RightMotorBackward = 12; //A0 12

const int AIA = 10; //A3 5

const int AIB = 9; //A2 6

const int BIA = 6; //A1 11

const int BIB = 12; //A0 12

byte speed = 255;

//sensor pins

#define trig_pin 3 //analog input 1 A0 A6 9

#define echo_pin 4 //analog input 2 A1 A7 10

#define maximum_distance 300

boolean goesForward = false;

int distance = 100;

NewPing sonar(trig_pin, echo_pin, maximum_distance); //sensor function

Servo servo_motor; //our servo name

void setup(){

//pinMode(RightMotorForward, OUTPUT);

//pinMode(LeftMotorForward, OUTPUT);

//pinMode(LeftMotorBackward, OUTPUT);

//pinMode(RightMotorBackward, OUTPUT);

pinMode(AIA, OUTPUT);

pinMode(AIB, OUTPUT);

pinMode(BIA, OUTPUT);

pinMode(BIB, OUTPUT);

Serial.begin(9600); // Starts the serial communication

servo_motor.attach(11); //our servo pin A5 13

servo_motor.write(115);

delay(2000);

distance = readPing();

delay(100);

distance = readPing();

delay(100);

distance = readPing();

delay(100);

distance = readPing();

delay(100);

}

void loop(){

int distanceRight = 0;

int distanceLeft = 0;

delay(50);

if (distance <= 20){

moveStop();

delay(300);

moveBackward();

delay(400);

moveStop();

delay(300);

distanceRight = lookRight();

delay(300);

distanceLeft = lookLeft();

delay(300);

if (distance >= distanceLeft){

turnRight();

moveStop();

}

else{

turnLeft();

moveStop();

}

else{

moveForward();

}

distance = readPing();

// Prints the distance on the Serial Monitor

Serial.print("Distance: ");

Serial.println(distance);

}

int lookRight(){

servo_motor.write(50);

delay(500);

int distance = readPing();

delay(100);

servo_motor.write(115);

return distance;

}

int lookLeft(){

servo_motor.write(170);

delay(500);

int distance = readPing();

delay(100);

servo_motor.write(115);

return distance;

delay(100);

}

int readPing(){

delay(70);

int cm = sonar.ping_cm();

if (cm==0){

cm=250;

}

return cm;

}

void moveStop(){

//analogWrite(RightMotorForward, 0);

//analogWrite(LeftMotorForward, 0);

//analogWrite(RightMotorBackward, 0);

//analogWrite(LeftMotorBackward, 0);

analogWrite(AIA, 0);

analogWrite(AIB, 0);

analogWrite(BIA, 0);

analogWrite(BIB, 0);

}

void moveForward(){

if(!goesForward){

goesForward=true;

//analogWrite(LeftMotorForward, 90);

//analogWrite(RightMotorForward, 95);

//analogWrite(LeftMotorBackward, 0);

//analogWrite(RightMotorBackward, 0);

analogWrite(AIA, speed);

analogWrite(AIB, 0);

analogWrite(BIA, speed);

analogWrite(BIB, 0);

}

void moveBackward(){

goesForward=false;

//analogWrite(LeftMotorBackward, 90);

//analogWrite(RightMotorBackward, 95);

//analogWrite(LeftMotorForward, 0);

//analogWrite(RightMotorForward, 0);

analogWrite(AIA, 0);

analogWrite(AIB, speed);

analogWrite(BIA, 0);

analogWrite(BIB, speed);

}

void turnRight(){

//analogWrite(LeftMotorForward, 90);

//analogWrite(RightMotorBackward, 95);

//analogWrite(LeftMotorBackward, 0);

//analogWrite(RightMotorForward, 0);

analogWrite(AIA, speed);

analogWrite(AIB, 0);

analogWrite(BIA, 0);

analogWrite(BIB, speed);

delay(450);

//analogWrite(LeftMotorForward, 90); //(AIA, speed)

//analogWrite(RightMotorForward, 95); //(BIA, speed)

//analogWrite(LeftMotorBackward, 0); //(AIB, 0)

//analogWrite(RightMotorBackward, 0); //(BIB, 0)

analogWrite(AIA, speed);

analogWrite(AIB, 0);

analogWrite(BIA, speed);

analogWrite(BIB, 0);

}

void turnLeft(){

//analogWrite(LeftMotorBackward, 90); //(AIB, 0)

//analogWrite(RightMotorForward, 95); //(BIA, speed)

//analogWrite(LeftMotorForward, 0); //(AIA, speed)

//analogWrite(RightMotorBackward, 0); //(BIB, 0)

analogWrite(AIA, 0);

analogWrite(AIB, speed);

analogWrite(BIA, speed);

analogWrite(BIB, 0);

delay(450);

//analogWrite(LeftMotorForward, 90); //(AIA, speed)

//analogWrite(RightMotorForward, 95); //(BIA, speed)

//analogWrite(LeftMotorBackward, 0); //(AIB, 0)

//analogWrite(RightMotorBackward, 0); //(BIB, 0)

analogWrite(AIA, speed);

analogWrite(AIB, 0);

analogWrite(BIA, speed);

analogWrite(BIB, 0);

}

Now the set-backs... yellow motor left hand side does not drive/spin well or at all... I need to dig through my boxes of components to find more....HC-SR04 needed mounting holes enlarged (but you knew they would)...figuring how to split the battery box into two separate supplies...

I needed to locate metal eyelets, screws, washers and nuts to be used to connect "dupont wires" from accessories to Circuit Playground Express...

Its again been a few weeks..2 months actually... since revisiting this build. Needed to create jumpers to tie all grounds together, Then build 2k/1k resistor voltage divider jumper for HC-SR04 sensor to go from "ECHO" to Circuit Playground Express pin (the echo return will be a 3.3vdc pulse that can be processed via the code).

CPE Robot on desktop

Desktop Trial

1st Floor Test

2nd Floor Test with weak batteries poor cable management via electrical tape

CPR Robot floor test with weak batteries

I am powering this build with separate 3 power packs; two (2x3.7vdc batteries-18650 Li-Ion) each: 1st to "5vdc regulator" for servo and HC-SR04 and 2nd to DC Motor/L9110S and 3rd 3.7vdc Lipo from Adafruit for Circuit Playground Express.

There is enough "juice" on Desktop to test code and Motor functions and reaction to HC-SR04 and obstacles, but these "old" batteries don't last long enough on floor with the higher DC motor current draw from my left wheel.

At least it all works now. My cable management could be alot better (using shorter wires) and a better support with standoffs for the Circuit Playground Express board. Most of all, better access to batteries or a different power schema...or even a 2nd/top platform for the CPE

Code

/*
  from https://www.bananarobotics.com/shop/How-to-use-the-HG7881-(L9110)-Dual-Channel-Motor-Driver-Module
  HG7881_Motor_Driver_Example - Arduino sketch
   
  This example shows how to drive a motor with using HG7881 (L9110) Dual
  Channel Motor Driver Module.  For simplicity, this example shows how to
  drive a single motor.  Both channels work the same way.
   
  This example is meant to illustrate how to operate the motor driver
  and is not intended to be elegant, efficient or useful.
   
  Connections:
   
    Arduino digital output D10 to motor driver input B-IA.
    Arduino digital output D11 to motor driver input B-IB.
    Motor driver VCC to operating voltage 5V.
    Motor driver GND to common ground.
    Motor driver MOTOR B screw terminals to a small motor.
     
  Related Banana Robotics items:
   
    BR010038 HG7881 (L9110) Dual Channel Motor Driver Module
    https://www.BananaRobotics.com/shop/HG7881-(L9110)-Dual-Channel-Motor-Driver-Module
 
  https://www.BananaRobotics.com
*/
 
// wired connections
#define HG7881_B_IA 10 // D10 --> Motor B Input A --> MOTOR B +
#define HG7881_B_IB 11 // D11 --> Motor B Input B --> MOTOR B -
 
// functional connections
#define MOTOR_B_PWM HG7881_B_IA // Motor B PWM Speed
#define MOTOR_B_DIR HG7881_B_IB // Motor B Direction
 
// the actual values for "fast" and "slow" depend on the motor
#define PWM_SLOW 50  // arbitrary slow speed PWM duty cycle
#define PWM_FAST 200 // arbitrary fast speed PWM duty cycle
#define DIR_DELAY 1000 // brief delay for abrupt motor changes
 
void setup()
{
  Serial.begin( 9600 );
  pinMode( MOTOR_B_DIR, OUTPUT );
  pinMode( MOTOR_B_PWM, OUTPUT );
  digitalWrite( MOTOR_B_DIR, LOW );
  digitalWrite( MOTOR_B_PWM, LOW );
}
 
void loop()
{
  boolean isValidInput;
  // draw a menu on the serial port
  Serial.println( "-----------------------------" );
  Serial.println( "MENU:" );
  Serial.println( "1) Fast forward" );
  Serial.println( "2) Forward" );
  Serial.println( "3) Soft stop (coast)" );
  Serial.println( "4) Reverse" );
  Serial.println( "5) Fast reverse" );
  Serial.println( "6) Hard stop (brake)" );
  Serial.println( "-----------------------------" );
  do
  {
    byte c;
    // get the next character from the serial port
    Serial.print( "?" );
    while( !Serial.available() )
      ; // LOOP...
    c = Serial.read();
    // execute the menu option based on the character recieved
    switch( c )
    {
      case '1': // 1) Fast forward
        Serial.println( "Fast forward..." );
        // always stop motors briefly before abrupt changes
        digitalWrite( MOTOR_B_DIR, LOW );
        digitalWrite( MOTOR_B_PWM, LOW );
        delay( DIR_DELAY );
        // set the motor speed and direction
        digitalWrite( MOTOR_B_DIR, HIGH ); // direction = forward
        analogWrite( MOTOR_B_PWM, 255-PWM_FAST ); // PWM speed = fast
        isValidInput = true;
        break;      
         
      case '2': // 2) Forward      
        Serial.println( "Forward..." );
        // always stop motors briefly before abrupt changes
        digitalWrite( MOTOR_B_DIR, LOW );
        digitalWrite( MOTOR_B_PWM, LOW );
        delay( DIR_DELAY );
        // set the motor speed and direction
        digitalWrite( MOTOR_B_DIR, HIGH ); // direction = forward
        analogWrite( MOTOR_B_PWM, 255-PWM_SLOW ); // PWM speed = slow
        isValidInput = true;
        break;      
         
      case '3': // 3) Soft stop (preferred)
        Serial.println( "Soft stop (coast)..." );
        digitalWrite( MOTOR_B_DIR, LOW );
        digitalWrite( MOTOR_B_PWM, LOW );
        isValidInput = true;
        break;      
 
      case '4': // 4) Reverse
        Serial.println( "Fast forward..." );
        // always stop motors briefly before abrupt changes
        digitalWrite( MOTOR_B_DIR, LOW );
        digitalWrite( MOTOR_B_PWM, LOW );
        delay( DIR_DELAY );
        // set the motor speed and direction
        digitalWrite( MOTOR_B_DIR, LOW ); // direction = reverse
        analogWrite( MOTOR_B_PWM, PWM_SLOW ); // PWM speed = slow
        isValidInput = true;
        break;      
         
      case '5': // 5) Fast reverse
        Serial.println( "Fast forward..." );
        // always stop motors briefly before abrupt changes
        digitalWrite( MOTOR_B_DIR, LOW );
        digitalWrite( MOTOR_B_PWM, LOW );
        delay( DIR_DELAY );
        // set the motor speed and direction
        digitalWrite( MOTOR_B_DIR, LOW ); // direction = reverse      
        analogWrite( MOTOR_B_PWM, PWM_FAST ); // PWM speed = fast
        isValidInput = true;
        break;
         
      case '6': // 6) Hard stop (use with caution)
        Serial.println( "Hard stop (brake)..." );
        digitalWrite( MOTOR_B_DIR, HIGH );
        digitalWrite( MOTOR_B_PWM, HIGH );
        isValidInput = true;
        break;      
         
      default:
        // wrong character! display the menu again!
        isValidInput = false;
        break;
    }
  } while( isValidInput == true );
 
  // repeat the main loop and redraw the menu...
}
/*EOF*/

#include <Servo.h>          //Servo motor library. This is standard library
#include <NewPing.h>        //Ultrasonic sensor function library. You must install this library
//#include <Ultrasonic.h>
//our L298N L9110 control pins
//const int LeftMotorForward = 10; //A3 5
//const int LeftMotorBackward = 9; //A2 6
//const int RightMotorForward = 6; //A1 11
//const int RightMotorBackward = 12; //A0 12
const int AIA = 10; //A3 5
const int AIB = 9; //A2 6
const int BIA = 6; //A1 11
const int BIB = 12; //A0 12
byte speed = 255;

//sensor pins
#define trig_pin 3 //analog input 1 A0 A6 9
#define echo_pin 4 //analog input 2 A1 A7 10

#define maximum_distance 300
boolean goesForward = false;
int distance = 100;



NewPing sonar(trig_pin, echo_pin, maximum_distance); //sensor function
Servo servo_motor; //our servo name


void setup(){

  //pinMode(RightMotorForward, OUTPUT);
  //pinMode(LeftMotorForward, OUTPUT);
  //pinMode(LeftMotorBackward, OUTPUT);
  //pinMode(RightMotorBackward, OUTPUT);
  pinMode(AIA, OUTPUT);
  pinMode(AIB, OUTPUT);
  pinMode(BIA, OUTPUT);
  pinMode(BIB, OUTPUT); 
  Serial.begin(9600); // Starts the serial communication



  servo_motor.attach(11); //our servo pin A5 13

  servo_motor.write(115);
  delay(2000);
  distance = readPing();
  delay(100);
  distance = readPing();
  delay(100);
  distance = readPing();
  delay(100);
  distance = readPing();
  delay(100);
}

void loop(){
  


  int distanceRight = 0;
  int distanceLeft = 0;
  delay(50);

  if (distance <= 20){
    moveStop();
    delay(300);
    moveBackward();
    delay(400);
    moveStop();
    delay(300);
    distanceRight = lookRight();
    delay(300);
    distanceLeft = lookLeft();
    delay(300);

    if (distance >= distanceLeft){
      turnRight();
      moveStop();
    }
    else{
      turnLeft();
      moveStop();
    }
  }
  else{
    moveForward(); 
  }
    distance = readPing();
    // Prints the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.println(distance);
}

int lookRight(){  
  servo_motor.write(50);
  delay(500);
  int distance = readPing();
  delay(100);
  servo_motor.write(115);
  return distance;
}

int lookLeft(){
  servo_motor.write(170);
  delay(500);
  int distance = readPing();
  delay(100);
  servo_motor.write(115);
  return distance;
  delay(100);
}

int readPing(){
  delay(70);
  int cm = sonar.ping_cm();
  if (cm==0){
    cm=250;
  }
  return cm;
}

void moveStop(){
  
  //analogWrite(RightMotorForward, 0);
  //analogWrite(LeftMotorForward, 0);
  //analogWrite(RightMotorBackward, 0);
  //analogWrite(LeftMotorBackward, 0);
  analogWrite(AIA, 0);
  analogWrite(AIB, 0);
  analogWrite(BIA, 0);
  analogWrite(BIB, 0);
}

void moveForward(){

  if(!goesForward){

    goesForward=true;
    
    //analogWrite(LeftMotorForward, 90);
    //analogWrite(RightMotorForward, 95);
    //analogWrite(LeftMotorBackward, 0);
    //analogWrite(RightMotorBackward, 0); 
    analogWrite(AIA, speed);
    analogWrite(AIB, 0);
    analogWrite(BIA, speed);
    analogWrite(BIB, 0); 

  }
}

void moveBackward(){

  
    goesForward=false;

  //analogWrite(LeftMotorBackward, 90);
  //analogWrite(RightMotorBackward, 95);  
  //analogWrite(LeftMotorForward, 0);
  //analogWrite(RightMotorForward, 0);
  analogWrite(AIA, 0);
  analogWrite(AIB, speed);
  analogWrite(BIA, 0);
  analogWrite(BIB, speed);

}

void turnRight(){

  //analogWrite(LeftMotorForward, 90);
  //analogWrite(RightMotorBackward, 95);  
  //analogWrite(LeftMotorBackward, 0);
  //analogWrite(RightMotorForward, 0);
  analogWrite(AIA, speed);
  analogWrite(AIB, 0);
  analogWrite(BIA, 0);
  analogWrite(BIB, speed);
  
  delay(450);
  
  //analogWrite(LeftMotorForward, 90); //(AIA, speed)
  //analogWrite(RightMotorForward, 95); //(BIA, speed) 
  //analogWrite(LeftMotorBackward, 0); //(AIB, 0)
  //analogWrite(RightMotorBackward, 0); //(BIB, 0)
  analogWrite(AIA, speed);
  analogWrite(AIB, 0);
  analogWrite(BIA, speed);
  analogWrite(BIB, 0); 
  
}

void turnLeft(){

  //analogWrite(LeftMotorBackward, 90); //(AIB, 0)
  //analogWrite(RightMotorForward, 95);  //(BIA, speed)
  //analogWrite(LeftMotorForward, 0); //(AIA, speed)
  //analogWrite(RightMotorBackward, 0); //(BIB, 0)
  analogWrite(AIA, 0);
  analogWrite(AIB, speed);
  analogWrite(BIA, speed);
  analogWrite(BIB, 0);

  
  delay(450);
  
  //analogWrite(LeftMotorForward, 90); //(AIA, speed)
  //analogWrite(RightMotorForward, 95); //(BIA, speed)
  //analogWrite(LeftMotorBackward, 0); //(AIB, 0)
  //analogWrite(RightMotorBackward, 0); //(BIB, 0)
  analogWrite(AIA, speed);
  analogWrite(AIB, 0);
  analogWrite(BIA, speed);
  analogWrite(BIB, 0);

}

/*
 code example from http://arduinobasics.blogspot.com/2012/11/hc-sr04-ultrasonic-sensor.html
 HC-SR04 Ping distance sensor:
 VCC to arduino 5v 
 GND to arduino GND
 Echo to Arduino pin 7 
 Trig to Arduino pin 8
 
 This sketch originates from Virtualmix: http://goo.gl/kJ8Gl
 Has been modified by Winkle ink here: http://winkleink.blogspot.com.au/2012/05/arduino-hc-sr04-ultrasonic-distance.html
 And modified further by ScottC here: http://arduinobasics.blogspot.com.au/2012/11/arduinobasics-hc-sr04-ultrasonic-sensor.html
 on 10 Nov 2012.
 */


#define echoPin 7 // Echo Pin
#define trigPin 8 // Trigger Pin
#define LEDPin 13 // Onboard LED

int maximumRange = 200; // Maximum range needed
int minimumRange = 0; // Minimum range needed
long duration, distance; // Duration used to calculate distance

void setup() {
 Serial.begin (9600);
 pinMode(trigPin, OUTPUT);
 pinMode(echoPin, INPUT);
 pinMode(LEDPin, OUTPUT); // Use LED indicator (if required)
}

void loop() {
/* The following trigPin/echoPin cycle is used to determine the
 distance of the nearest object by bouncing soundwaves off of it. */ 
 digitalWrite(trigPin, LOW); 
 delayMicroseconds(2); 

 digitalWrite(trigPin, HIGH);
 delayMicroseconds(10); 
 
 digitalWrite(trigPin, LOW);
 duration = pulseIn(echoPin, HIGH);
 
 //Calculate the distance (in cm) based on the speed of sound.
 distance = duration/58.2;
 
 if (distance >= maximumRange || distance <= minimumRange){
 /* Send a negative number to computer and Turn LED ON 
 to indicate "out of range" */
 Serial.println("-1");
 digitalWrite(LEDPin, HIGH); 
 }
 else {
 /* Send the distance to the computer using Serial protocol, and
 turn LED OFF to indicate successful reading. */
 Serial.println(distance);
 digitalWrite(LEDPin, LOW); 
 }
 
 //Delay 50ms before next reading.
 delay(50);
}

//http://www.instructables.com/id/Arduino-Ultimate-Obstacle-Avoiding-Robot/
//Be sure to check pinouts-these are defaults from other Arduino's
//https://www.robotshop.com/letsmakerobots/files/Code_for_Obstacle_Avoidance_Arduino_Robot.txt

#include "IRremote.h"
#include <Servo.h>

//Pins for motor A 
const int MotorA1 = 6;
const int MotorA2 = 7; 
//Pins for motor B 
const int MotorB1 = 8;
const int MotorB2 = 9;
//Pins for ultrasonic sensor
const int trigger=10;
const int echo=11;

int leftscanval, centerscanval, rightscanval, ldiagonalscanval, rdiagonalscanval;
char choice;
  
//Pin for IR control
int receiver = 12; // pin 1 of IR receiver to Arduino digital pin 12
IRrecv irrecv(receiver);           // create instance of 'irrecv'
decode_results results; 
char contcommand;
int modecontrol=0;
int power=0;

const int distancelimit = 27; //Distance limit for obstacles in front           
const int sidedistancelimit = 12; //Minimum distance in cm to obstacles at both sides (the robot will allow a shorter distance sideways)

int distance;
int numcycles = 0;
char turndirection; //Gets 'l', 'r' or 'f' depending on which direction is obstacle free
const int turntime = 900; //Time the robot spends turning (miliseconds)
int thereis;
Servo head;

void setup(){
  head.attach(5);
  head.write(80);
  irrecv.enableIRIn(); // Start the IR receiver
  pinMode(MotorA1, OUTPUT); 
  pinMode(MotorA2, OUTPUT); 
  pinMode(MotorB1, OUTPUT); 
  pinMode(MotorB2, OUTPUT);
  pinMode(trigger,OUTPUT);
  pinMode(echo,INPUT);
  //Variable inicialization
  digitalWrite(MotorA1,LOW);
  digitalWrite(MotorA2,LOW);
  digitalWrite(MotorB1,LOW);
  digitalWrite(MotorB2,LOW);
  digitalWrite(trigger,LOW);
}

void go(){ 
   digitalWrite (MotorA1, HIGH);                              
   digitalWrite (MotorA2, LOW); 
   digitalWrite (MotorB1, HIGH); 
   digitalWrite (MotorB2, LOW);
}

void backwards(){
  digitalWrite (MotorA1 , LOW);                              
  digitalWrite (MotorA2, HIGH); 
  digitalWrite (MotorB1, LOW); 
  digitalWrite (MotorB2, HIGH);
}

int watch(){
  long howfar;
  digitalWrite(trigger,LOW);
  delayMicroseconds(5);                                                                              
  digitalWrite(trigger,HIGH);
  delayMicroseconds(15);
  digitalWrite(trigger,LOW);
  howfar=pulseIn(echo,HIGH);
  howfar=howfar*0.01657; //how far away is the object in cm
  return round(howfar);
}

void turnleft(int t){
  digitalWrite (MotorA1, LOW);                              
  digitalWrite (MotorA2, HIGH); 
  digitalWrite (MotorB1, HIGH); 
  digitalWrite (MotorB2, LOW);
  delay(t);
}

void turnright(int t){
  digitalWrite (MotorA1, HIGH);                              
  digitalWrite (MotorA2, LOW); 
  digitalWrite (MotorB1, LOW); 
  digitalWrite (MotorB2, HIGH);
  delay(t);
}  

void stopmove(){
  digitalWrite (MotorA1 ,LOW);                              
  digitalWrite (MotorA2, LOW); 
  digitalWrite (MotorB1, LOW); 
  digitalWrite (MotorB2, LOW);
}  

void watchsurrounding(){ //Meassures distances to the right, left, front, left diagonal, right diagonal and asign them in cm to the variables rightscanval, 
                         //leftscanval, centerscanval, ldiagonalscanval and rdiagonalscanval (there are 5 points for distance testing)
  centerscanval = watch();
  if(centerscanval<distancelimit){stopmove();}
  head.write(120);
  delay(100);
  ldiagonalscanval = watch();
  if(ldiagonalscanval<distancelimit){stopmove();}
  head.write(160); //Didn't use 180 degrees because my servo is not able to take this angle
  delay(300);
  leftscanval = watch();
  if(leftscanval<sidedistancelimit){stopmove();}
  head.write(120);
  delay(100);
  ldiagonalscanval = watch();
  if(ldiagonalscanval<distancelimit){stopmove();}
  head.write(80); //I used 80 degrees because its the central angle of my 160 degrees span (use 90 degrees if you are moving your servo through the whole 180 degrees)
  delay(100);
  centerscanval = watch();
  if(centerscanval<distancelimit){stopmove();}
  head.write(40);
  delay(100);
  rdiagonalscanval = watch();
  if(rdiagonalscanval<distancelimit){stopmove();}
  head.write(0);
  delay(100);
  rightscanval = watch();
  if(rightscanval<sidedistancelimit){stopmove();}

  head.write(80); //Finish looking around (look forward again)
  delay(300);
}

char decide(){
  watchsurrounding();
  if (leftscanval>rightscanval && leftscanval>centerscanval){
    choice = 'l';
  }
  else if (rightscanval>leftscanval && rightscanval>centerscanval){
    choice = 'r';
  }
  else{
    choice = 'f';
  }
  return choice;
}

void translateIR() { //Used when robot is switched to operate in remote control mode
  switch(results.value)
  {
  case 0xFF629D: //Case 'FORWARD'
    go();
    break;
  case 0xFF22DD: //Case 'LEFT'
    turnleft(turntime); 
    stopmove();  
    break;
  case 0xFF02FD: //Case 'OK'
    stopmove();   
    break;
  case 0xFFC23D: //Case 'RIGHT'
    turnright(turntime);
    stopmove(); 
    break;
  case 0xFFA857: //Case 'REVERSE'
    backwards();
    break;
  case 0xFF42BD:  //Case '*'
    modecontrol=0; stopmove(); // If an '*' is received, switch to automatic robot operating mode
    break;
  default: 
    ;
  }// End Case
  delay(500); // Do not get immediate repeat
} 

void loop(){
  
  if (irrecv.decode(&results)){ //Check if the remote control is sending a signal
    if(results.value==0xFF6897){ //If an '1' is received, turn on robot
      power=1; }
    if(results.value==0xFF4AB5){ //If a '0' is received, turn off robot
      stopmove();
      power=0; }
    if(results.value==0xFF42BD){ //If an '*' is received, switch operating mode from automatic robot to remote control (press also "*" to return to automatic robot mode)
      modecontrol=1; //  Activate remote control operating mode
      stopmove(); //The robot stops and starts responding to the user's directions
    }
    irrecv.resume(); // receive the next value
  }
  
  while(modecontrol==1){ //The system gets into this loop during the remote control mode until modecontrol=0 (with '*')
    if (irrecv.decode(&results)){ //If something is being received
      translateIR();//Do something depending on the signal received
      irrecv.resume(); // receive the next value
     }
  }
  if(power==1){
  go();  // if nothing is wrong go forward using go() function above.
  ++numcycles;
  if(numcycles>130){ //Watch if something is around every 130 loops while moving forward 
    watchsurrounding();
    if(leftscanval<sidedistancelimit || ldiagonalscanval<distancelimit){
      turnright(turntime);
    }
    if(rightscanval<sidedistancelimit || rdiagonalscanval<distancelimit){
      turnleft(turntime);
    }
    numcycles=0; //Restart count of cycles
  }
  distance = watch(); // use the watch() function to see if anything is ahead (when the robot is just moving forward and not looking around it will test the distance in front)
  if (distance<distancelimit){ // The robot will just stop if it is completely sure there's an obstacle ahead (must test 25 times) (needed to ignore ultrasonic sensor's false signals)
      ++thereis;}
  if (distance>distancelimit){
      thereis=0;} //Count is restarted
  if (thereis > 25){
    stopmove(); // Since something is ahead, stop moving.
    turndirection = decide(); //Decide which direction to turn.
    switch (turndirection){
      case 'l':
        turnleft(turntime);
        break;
      case 'r':
        turnright(turntime);
        break;
      case 'f':
        ; //Do not turn if there was actually nothing ahead
        break;
    }
    thereis=0;
  }
 }
}

#include <Servo.h>          //Servo motor library. This is standard library
#include <NewPing.h>        //Ultrasonic sensor function library. You must install this library
//#include <Ultrasonic.h>
//our L298N control pins
const int LeftMotorForward = A3; //A3 5
const int LeftMotorBackward = A2; //A2 6
const int RightMotorForward = A1; //A1 11
const int RightMotorBackward = A0; //A0 12


//sensor pins
#define trig_pin A6 //analog input 1 A0 A6 9
#define echo_pin A7 //analog input 2 A1 A7 10

#define maximum_distance 200
boolean goesForward = false;
int distance = 100;



NewPing sonar(trig_pin, echo_pin, maximum_distance); //sensor function
Servo servo_motor; //our servo name


void setup(){

  pinMode(RightMotorForward, OUTPUT);
  pinMode(LeftMotorForward, OUTPUT);
  pinMode(LeftMotorBackward, OUTPUT);
  pinMode(RightMotorBackward, OUTPUT);
  Serial.begin(9600); // Starts the serial communication



  servo_motor.attach(A5); //our servo pin A5 13

  servo_motor.write(115);
  delay(2000);
  distance = readPing();
  delay(100);
  distance = readPing();
  delay(100);
  distance = readPing();
  delay(100);
  distance = readPing();
  delay(100);
}

void loop(){
  


  int distanceRight = 0;
  int distanceLeft = 0;
  delay(50);

  if (distance <= 20){
    moveStop();
    delay(300);
    moveBackward();
    delay(400);
    moveStop();
    delay(300);
    distanceRight = lookRight();
    delay(300);
    distanceLeft = lookLeft();
    delay(300);

    if (distance >= distanceLeft){
      turnRight();
      moveStop();
    }
    else{
      turnLeft();
      moveStop();
    }
  }
  else{
    moveForward(); 
  }
    distance = readPing();
    // Prints the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.println(distance);
}

int lookRight(){  
  servo_motor.write(50);
  delay(500);
  int distance = readPing();
  delay(100);
  servo_motor.write(115);
  return distance;
}

int lookLeft(){
  servo_motor.write(170);
  delay(500);
  int distance = readPing();
  delay(100);
  servo_motor.write(115);
  return distance;
  delay(100);
}

int readPing(){
  delay(70);
  int cm = sonar.ping_cm();
  if (cm==0){
    cm=250;
  }
  return cm;
}

void moveStop(){
  
  analogWrite(RightMotorForward, 0);
  analogWrite(LeftMotorForward, 0);
  analogWrite(RightMotorBackward, 0);
  analogWrite(LeftMotorBackward, 0);

}

void moveForward(){

  if(!goesForward){

    goesForward=true;
    
    analogWrite(LeftMotorForward, 90);
    analogWrite(RightMotorForward, 95);
  
    analogWrite(LeftMotorBackward, 0);
    analogWrite(RightMotorBackward, 0); 
    

  }
}

void moveBackward(){

  
    goesForward=false;

  analogWrite(LeftMotorBackward, 90);
  analogWrite(RightMotorBackward, 95);
  
  analogWrite(LeftMotorForward, 0);
  analogWrite(RightMotorForward, 0);


}

void turnRight(){

  analogWrite(LeftMotorForward, 90);
  analogWrite(RightMotorBackward, 95);
  
  analogWrite(LeftMotorBackward, 0);
  analogWrite(RightMotorForward, 0);

  
  delay(450);
  
  analogWrite(LeftMotorForward, 90);
  analogWrite(RightMotorForward, 95);
  
  analogWrite(LeftMotorBackward, 0);
  analogWrite(RightMotorBackward, 0);
  

 
  
  
}

void turnLeft(){

  analogWrite(LeftMotorBackward, 90);
  analogWrite(RightMotorForward, 95);
  
  analogWrite(LeftMotorForward, 0);
  analogWrite(RightMotorBackward, 0);


  
  delay(450);
  
  analogWrite(LeftMotorForward, 90);
  analogWrite(RightMotorForward, 95);
  
  analogWrite(LeftMotorBackward, 0);
  analogWrite(RightMotorBackward, 0);


}

Credits

James Martel

48 projects • 64 followers

Self taught Robotics platform developer with electronics background

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What Do I Build Next?...A CircuitPlaygroundExpressRobot

What Do I Build Next?...A CircuitPlaygroundExpressRobot

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Schematics

Additional Components Layouts

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Additional Components Layouts

Additional Components Layouts

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Additional Components Layouts

Code

Test code example for one motor

Circuit Playground Express, L9110S Motor Control, HC-SR04 Ultrasonic Sensor with Pan, with DC Motors

Test code example for HC-SR04 Ultrasonic Sensor

Test code example for Avoidance Robot

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James Martel

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