HC-SR04 Issue

i have several hc-sr04 ultrasonic sensors, , 2 of them stopped working. trying figure out if dead or not. bought them around 6-10 months ago, have had light use on time have owned them.

my setup:
6 hc-sr04 ultrasonic sensors
arduino mega 2560
windows 7
arduino 1.0.5

these sensors have been working past few weeks have been in on project. today 1 quit working, returns ~730 cm (works out 43 milliseconds). checked wiring, looked fine, no obvious damage sensor itself, took multimeter , poked around bit , compared working one, nothing looked different. took working 1 , swapped around non-working one. working 1 worked fine, let run 5 minutes, , still worked. bad 1 not work anywhere connected it. connected non-working sensor arduino new wiring, still did not work. 15 minutes later, 1 started doing same thing, 1 had stayed in spot whole time. repeated tests again , same, bad sensor not work anywhere, , others work in place.

here small part of code when broke:

code: [select]


const int ultrasonicpins[6][2] = {
 42,43,   //lb
 44,45,   //lf
 50,51,   //rb
 52,53,   //rf
 46,47,   //fl
 48,49};  //fr

#define lback 0
#define lfront 1
#define rback 2
#define rfront 3
#define fleft 4
#define fright 5
#define trig 0
#define echo 1

void setupultrasonic();
double ultrasoniccm(int ultrapin);

void setup()
{
 serial.begin(9600);

 setupultrasonic();
}

void loop()
{
 for(int i=0; < 6; i++)
 {
   serial.println(ultrasoniccm(i));

   delay(40);
 }

 serial.println(" ");
 delay(250);
}

void setupultrasonic()
{
 pinmode(ultrasonicpins[lback][trig], output);
 pinmode(ultrasonicpins[lback][echo], input);
 pinmode(ultrasonicpins[lfront][trig], output);
 pinmode(ultrasonicpins[lfront][echo], input);
 pinmode(ultrasonicpins[rback][trig], output);
 pinmode(ultrasonicpins[rback][echo], input);
 pinmode(ultrasonicpins[rfront][trig], output);
 pinmode(ultrasonicpins[rfront][echo], input);
 pinmode(ultrasonicpins[fleft][trig], output);
 pinmode(ultrasonicpins[fleft][echo], input);
 pinmode(ultrasonicpins[fright][trig], output);
 pinmode(ultrasonicpins[fright][echo], input);
}

double ultrasoniccm(int ultrapin)
{
 long dtime;

 digitalwrite(ultrasonicpins[ultrapin][trig], high);
 delaymicroseconds(10);
 digitalwrite(ultrasonicpins[ultrapin][trig], low);
 dtime = pulsein(ultrasonicpins[ultrapin][echo], high);
 return (dtime/2.00)*(340.29/10000.00);
}


once broke simplified down this:

code: [select]


double ultrasoniccm();

void setup()
{
 serial.begin(9600);

 pinmode(42, output);
 pinmode(43, input);
}

void loop()
{
 serial.println(ultrasoniccm());
 
 delay(250);
}

double ultrasoniccm()
{
 long dtime;

 digitalwrite(42, high);
 delaymicroseconds(10);
 digitalwrite(42, low);
 dtime = pulsein(43, high);
 return (dtime/2.00)*(340.29/10000.00);
}


i tried use newping library, return either 147cm or 0cm broken ones, , return values working ones (an occasional 0) . when did these tests swapped sensors around (working , non-working) on same port (one bad sensor  originally connected to).

i'd appreciate figuring out if these sensors died or if have issue.

thanks,
tr24em

unfortunately looks it's broken, if google "hc-sr04 broken", you'll find quite lot of similar stories.

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