Robot does nothing.

Hello, I am making a robot that goes through a maze for my science fair project. I am using an HC-SR04 to make it navigate and the microcontroller is an arduino mega 2560(clone). I had the code written and everything ready but when I uploaded the code two days ago, the servo went left quickly, right a little slower, and then stopped and it will not do anything else :confused: I checked the motors on a different code, and they work. So does the servo, there is plenty of power(I have 3-4 AA battery holders wired together(should be 12 volts…?)), and the only other thing I can think of is that the HC-SR04 is shorted out or something and that confuses(or messes up) the robot.

Here is the code:

//Arduno Maze-Solving OS Robot 
#include <AFMotor.h>//Include Library for motor sheild
#include <NewPing.h>//include Library for 'HC-SR04'
#include <Servo.h>//include Library for the servo
#define TRIGGER_PIN 15 //trigger is on this pin
#define ECHO_PIN 16//echo on this one
#define MAX_DISTANCE 50//max distance to wait for is 50 CM
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); //Setup newPing
const int BLED = 50;//the pin for blue LED
const int RLED = 46;//the pin for red LED
const int GLED = 48;//the pin for green LED
const int ArmSensor = 35;//the pin the bump sensor is on
int val = 0;//create variable for bump sensor
int old_val = 0;//old value of bump semsor
Servo Head;//Create servo "Head"
int distance = 0;//variable to Sense distance
int LeftDistance = 0;//used to store distance to the left
int RightDistance = 0;//used to store distance to the right
float HeadPosition;//used to move the servo that turns the head
AF_DCMotor Left(2);//left motor is on motor 2
AF_DCMotor Right(1);//right motor is on motor 1
AF_DCMotor Fan(3);//fan is on motor three
//const int LightSensor = 12;//light sensor is on analog pin 12
//int LightLevel;//used to calculate light level

void setup() {//(Goes through this at the begining when robot is powered up. doesn't repeat)
  pinMode(BLED, OUTPUT);//vvvvvvvvv
  pinMode(GLED, OUTPUT);//LED's are outputs
  pinMode(RLED, OUTPUT);//^^^^^^^^^
  pinMode(ArmSensor, INPUT);//bump sensor is an input
  Left.setSpeed(78);//set speed of left motor
  Left.run(RELEASE);//stop the left motor
  Right.setSpeed(75);//set speed of Right motor
  Right.run(RELEASE);//stop right motor
 // Fan.setSpeed(100);
 // Fan.run(FORWARD);
  Head.attach(10);//the head servo motor is on pin 10
 // Head.write(56);//move the head a little to make sure it works
  delay(300);//wait a little
}

void loop() {//(main code. repeats untill powered off)
  val = digitalRead(ArmSensor);//see if the bump sensor has been pressed
  if((val = HIGH) && (old_val = LOW)) {//if we have crashed
    STOP();//stop moving(wil not start back up untill reset button is pressed);
  }else{//otherwise
    old_val = val;//store as old val
   // delay(2000);
    scan();//scan to see distance
   // delay(2000);
    if(distance > 16){//if we have room
      Forward();//keep going forward
      delay(400);//for .4 of a second
      Brake();
    }else if(distance <= 16) {//otherwise the distance is (Probably) going to be < or equal to 16 CM
       for(HeadPosition = 56; HeadPosition = 130; HeadPosition +5) {
      Head.write(HeadPosition);//look to the left
      delay(15);
    }
       scan();//read distance
    //  delay(2000);
      distance = LeftDistance;//store the distance as left
    //  delay(2000);
       for(HeadPosition = 130; HeadPosition = 30; HeadPosition -5) {
      Head.write(30);//look to the right
      delay(15);//give time to get there
      }
      scan();//read distance
   //   delay(2000);
      distance = RightDistance;//store the distance as right
      if(LeftDistance > RightDistance) { //if there is more room to the left
        TurnLeft(); //turn left
        delay(200);//(aproxamately 90 degree's)
        Brake();
      }else if(RightDistance >= LeftDistance) { //if there is more room to the right 
        TurnRight();// turn right
        delay(200);//(aproxamately 90 degree's)
        Brake();  
      }
    }
  }
}

void Forward() {//defining function forward
  Left.run(FORWARD); Right.run(FORWARD);//make both wheels go forward
  digitalWrite(GLED, HIGH);
  digitalWrite(BLED, LOW);//signal with LEDs
  digitalWrite(RLED, LOW);
}
void TurnLeft() {//defining left
  Left.run(BACKWARD); Right.run(FORWARD);//make wheels go left
  digitalWrite(BLED, HIGH);
  digitalWrite(GLED, LOW);//signal with LEDs
  digitalWrite(RLED, LOW);
}
void TurnRight() {//defining right
  Left.run(FORWARD); Right.run(BACKWARD);//make wheels go right
  digitalWrite(RLED, HIGH);
  digitalWrite(GLED, LOW);//signaal with LED's
  digitalWrite(BLED, LOW);
}
void Backward() {//defining backward
  Left.run(BACKWARD); Right.run(BACKWARD);//make wheels go backward
  digitalWrite(GLED, HIGH);
  digitalWrite(BLED, HIGH);//signal with LED's
  digitalWrite(RLED, LOW);
}
void scan() {//defining scan
  delay(50);//pause between pings
  unsigned int uS = sonar.ping();///calculateing distance infront of us
  distance = uS / US_ROUNDTRIP_CM;//^^^
  digitalWrite(GLED, HIGH);
  digitalWrite(RLED, HIGH);//signal that we are scanning
  digitalWrite(BLED, LOW);
}
void Brake() {
  Left.run(RELEASE);Right.run(RELEASE);
}

 
void STOP() {//define how to stop
  Left.run(RELEASE);//stop left
  Right.run(RELEASE);//stop right
  Fan.run(RELEASE);//stop the fan
  digitalWrite(GLED, LOW);
  digitalWrite(BLED, HIGH);//signal that we are stopped
  digitalWrite(RLED, HIGH);
  Head.write(90.5);//turn head exactly to center
}

Oh and I haven’t built the maze yet (if that tells you anything that you need to know).

Thank you for your time

Sorry got that wrong: It looks RIGHT quickly, LEFT slower then stops

analogpin is not 12 why break after 0.5 seconds, just scan and if scan wants something else change the direction or speed. get the right and left distance back from the scan routine by using them in an integer.

if((val = HIGH) && (old_val = LOW))

Oh dear.

 for(HeadPosition = 130; HeadPosition = 30; HeadPosition -5)

Much more oopsiness

shooter: analogpin is not 12

?

Well the brake is just in the testing. I was planing on taking the brake out when I actually have it run through the maze. What do you guys mean analog pin is not 12? I have a pin 12 on the board I’m using

I don't dispute the presence of an analogue pin 12 on a Mega.

AWOL: if((val = HIGH) && (old_val = LOW))

Oh dear.

 for(HeadPosition = 130; HeadPosition = 30; HeadPosition -5)

Much more oopsiness

What do you mean by that? I didn't understand it.

The for loop has two faults.
What should be a comparison is an assignment, and the end of loop expression does nothing.

The if has two assignments which should be comparisons.

Ohhh so it should just be

if(val == HIGH) { ...

thank you I will try it

On top of the other problems already pointed out, there’s this one. It will lock the servo at 130 degrees.:-

for(HeadPosition = 56; HeadPosition = 130; HeadPosition +5) {
      Head.write(HeadPosition);//look to the left
      delay(15);
    }

Instead, maybe:-

for (HeadPosition = 56; HeadPosition <= 130; HeadPosition += 5)
{
    Head.write(HeadPosition);//look to the left
    delay(15);
}

(The one AWOL pointed out will lock the servo at 30 degrees):-

for(HeadPosition = 130; HeadPosition = 30; HeadPosition -5) {
      Head.write(30);//look to the right
      delay(15);//give time to get there
      }

And it would do that even if you hadn‚Äôt hard-coded 30 in the ‚ÄėHead.write()‚Äô call.

Edit: And there’s nothing actually wrong with this:-

unsigned int uS = sonar.ping();///calculateing distance infront of us
  distance = uS / US_ROUNDTRIP_CM;//^^^

but I just thought I’d point out that you can simplify it:-distance = sonar.ping_cm();  // calculating distance in front of us in cm.

Ok, Thank you for your help!

So I tried changing all those(which were all careless mistakes of mine, I'm sorry) and still nothing happened. BUT, when I took out the whole if loop right here:

void loop() {//(main code. repeats until powered off)
/*  val = digitalRead(ArmSensor);//see if the bump sensor has been pressed
  if(val = HIGH) {//if we have crashed
    STOP();//stop moving(will not start back up until reset button is pressed);
  }else{//otherwise*/......

It worked properly?What?! :confused: Oh well. at least it works, but can anyone tell me how to have it so that it will stop when the button is pressed, but without having that problem. Because at the moment I do not really trust the HC-SR04, at least not until I test it some more to make sure it is accurate.

Thank you I appreciate this guys,

if(val = HIGH)

I thought you said you'd got rid of the careless mistakes?

You have another assignment instead of an == comparison.

Oh. I though you meant it should only have one = sign. [u]My bad sorry[/u] sorry :fearful:

Thank you so much guys I'm really thankful. It works great now :) !