I am building a robot with multiple sensors, abilities etc. Since I had a bug with a HC-SR04 rotated by a servo, I experimented in a different sketch. If the distance is less than 30cm, the servo turns left and right. Since I need continuous readings of other sensors, I cannot use delays so I used millis in order to keep time. The sensor worked correctly in a different sketch, but something in the full one conflicts with it.
I decided to see what will happen if I start removing code. I removed most of the code that I did not need for this experiment. After the removal, the issue persisted. The sensor is still giving me 0s. Below, I will post the code where it does not work and gives me 0s. Notice that it is not the full code of the robot. I removed a lot of code to try to narrow it down. The full sketch is too long for me to post here. This is all the code that was left after I removed stuff:
#include <Servo.h>
//RTC_DS1307 rtc;
/*const int blue2 = 12;
const int blue1 = 11;
const int red1 = 10;
const int red2 = 9;
*/
Servo servo;
unsigned long counter;
unsigned long prevMillis = 0;
int piezoInterval = 200;
int drivingMode = 0;
boolean playPiezo=false;
#define trig 22
#define echo 24
long duration;
boolean turned150 = false;
int cm30, cm, cm150;
bool checkLeft = false;
boolean checkRight = false;
boolean mainPing = true;
unsigned long servoTimer = millis();
void setup(){
servo.attach(12);
/* for(int i=0;i<sizeof(leds)/sizeof(leds[0]);i++){
pinMode(leds[i], OUTPUT);
}
*/
Serial.begin(9600);
servo.write(90);
delay(200);
}
void loop(){
counter=millis();
//Serial.print("Millis1: ");
//Serial.println(millis());
/* if(irrecv.decode(&results)){
translateIR();
irrecv.resume();
}*/
// Serial.print("Millis2: ");
if(drivingMode == 0){
if(((counter-servoTimer) >= 150) && mainPing){
ping();
cm=duration/29.1/2;
Serial.println(cm);
counter=millis();
servoTimer=counter;
}
if((cm<30) && mainPing){
mainPing=false;
checkRight = true;
counter=millis();
servoTimer=millis();
servo.write(150);
cm=30;
}
if(checkRight && !checkLeft && ((counter-servoTimer) >= 170)){
ping();
checkLeft=true;
cm150 = duration/29.1/2;
counter=millis();
servoTimer=millis();
servo.write(50);
}
if(checkRight && checkLeft && ((counter-servoTimer) >= 340)){
checkRight=false;
checkLeft=false;
mainPing=true;
ping();
cm30 = duration/29.1/2;
counter=millis();
servoTimer=millis();
servo.write(90);
}
}
//getTime();
//existsFire();
/*if(!manualLeds){
readPhoto();
}*/
delay(2);
}
//}
void ping(){
digitalWrite(trig, LOW);
delayMicroseconds(2);
digitalWrite(trig, HIGH);
delayMicroseconds(10);
digitalWrite(trig, LOW);
duration = pulseIn(echo, HIGH, 24000L);
}
Maybe this means that the issue is within this remaining code. Of course I will need all of the code that I removed for the final project, but I was just trying to debug.
I made my code a lot more concise since the posted code draft, but the ultrasonic sensor still gives me 0s. I do not understand what can affect its performance as it works fine in my other sketch.
I tried connecting the sensor to an external 5 volt power source and the same thing happened. The reason for the issue is not because if my power source.
I used to have a small delay at the end of my code and I removed that in order to make it run faster. Since pulseIn is blocking for 24ms, the delays do not affect it and it should work normally. But it does not.
Also, the sensor is giving 0s not because the target is too far away. Even if I put my hand close, it still gives 0s. If I make the cm equal 400 if the duration equals 0, the cm are always 400 regardless of the distance from the sensor.