Ultasonic sensors

hi there need advice, found code  , use sensors, want know if work sensors start @ same time dont understand code well, if please tell me first of if work , second need change in code?

thank



#include <newping.h>

#define sonar_num     3 // number of sensors.
#define max_distance 200 // maximum distance (in cm) ping.
#define ping_interval 0 // milliseconds between sensor pings (29ms min avoid cross-sensor echo).

unsigned long pingtimer[sonar_num]; // holds times when next ping should happen each sensor.
unsigned int cm[sonar_num];         // ping distances stored.
uint8_t currentsensor = 0;          // keeps track of sensor active.

newping sonar[sonar_num] = {     // sensor object array.
  newping(6, 7, max_distance), // each sensor's trigger pin, echo pin, , max distance ping.
  newping(8, 9, max_distance),
  newping(11, 12, max_distance)
};

void setup() {
  serial.begin(115200);
  pingtimer[0] = millis() + 75;           // first ping starts @ 75ms, gives time arduino chill before starting.
  (uint8_t = 1; < sonar_num; i++) // set starting time each sensor - can change make them start    @ same time??
    pingtimer = pingtimer[i - 1] + ping_interval;
}

void loop() {
  (uint8_t = 0; < sonar_num; i++) { // loop through sensors.
    if (millis() >= pingtimer) {         // sensor's time ping?
      pingtimer += ping_interval * sonar_num;  // set next time sensor pinged.
      if (i == 0 && currentsensor == sonar_num - 1) onesensorcycle(); // sensor ping cycle complete, results.
      sonar[currentsensor].timer_stop();          // make sure previous timer canceled before starting new ping (insurance).
      currentsensor = i;                                            // sensor being accessed.
      cm[currentsensor] = 0;                                 // make distance 0 in case there's no ping echo sensor.
      sonar[currentsensor].ping_timer(echocheck); // ping (processing continues, interrupt call echocheck echo).
    }
  }
  // other code *doesn't* analyze ping results can go here.
}

void echocheck() { // if ping received, set sensor distance array.
  if (sonar[currentsensor].check_timer())
    cm[currentsensor] = sonar[currentsensor].ping_result / us_roundtrip_cm;
}

void onesensorcycle() { // sensor ping cycle complete, results.
  // following code replaced code ping results.
  (uint8_t = 0; < sonar_num; i++) {
    serial.print(i);
    serial.print("=");
    serial.print(cm);
    serial.print("cm ");
  }
  serial.println();
}

now can see why ask use code tags when posting code?

Arduino Forum > Using Arduino > Project Guidance > Ultasonic sensors

arduino