Weird PPM readings

hi,

i getting weird readings of ppm spektrum ar8000 receiver on data/bind port (supposed ppm signal according reply spektrum).

i using arduino pro mini 3v/8mhz clone.

here's code:

code: [select]

#define pin                  2      // arduino pro mini 3v/8mhz
#define n                  100      // max channels
#define frameendthreshold 4000

int chans[n];
int next;                           // next position in chans
bool capturing = false;

void setup() {
  serial.begin(115200);
  pinmode(pin, input);
}

void loop() {
  int w = pulsein(pin, high);
 
  if (capturing) {
    if (next < n) {                 // record channel
      chans[next] = w;
      next++;
    }

    if (w > frameendthreshold) {    // print if frame end detected
      serial.print(next);
      serial.print(": ");
      (int = 0; < next; i++) {
        serial.print(chans[i]);
        serial.print(i != (next - 1) ? " - " : "\n");
      }
      capturing = false;
    }

  } else {
    if (w > frameendthreshold) {    // start recording if frame end detected
      capturing = true;
      next = 0;
    }
  }
}

here's example output:

code: [select]

⸮4⸮4⸮⸮$4⸮\⸮⸮$t⸮\⸮⸮e⸮⸮⸮⸮⸮⸮⸮$4⸮4⸮⸮⸮4⸮⸮$4д⸮⸮$4⸮⸮⸮⸮e⸮t⸮⸮⸮⸮^d⸮.⸮⸮%⸮⸮⸮⸮⸮⸮⸮$⸮^⸮$⸮17: 9 - 9 - 18 - 9 - 9 - 9 - 9 - 18 - 78 - 9 - 27 - 18 - 79 - 9 - 9 - 9 - 20484
19: 9 - 9 - 18 - 9 - 9 - 9 - 9 - 9 - 26 - 18 - 72 - 9 - 27 - 18 - 79 - 10 - 9 - 9 - 20511
17: 9 - 9 - 9 - 9 - 10 - 9 - 26 - 18 - 78 - 9 - 27 - 18 - 78 - 9 - 9 - 9 - 20466
16: 9 - 9 - 18 - 9 - 9 - 9 - 9 - 18 - 79 - 10 - 18 - 79 - 9 - 9 - 9 - 20544
17: 10 - 9 - 18 - 9 - 6 - 9 - 9 - 18 - 78 - 9 - 27 - 18 - 79 - 10 - 9 - 9 - 20458
17: 9 - 9 - 18 - 9 - 9 - 9 - 10 - 18 - 79 - 9 - 26 - 18 - 78 - 9 - 9 - 9 - 20520
17: 10 - 9 - 18 - 9 - 10 - 9 - 9 - 18 - 78 - 9 - 27 - 18 - 78 - 9 - 9 - 9 - 20459
17: 9 - 9 - 18 - 9 - 9 - 9 - 9 - 18 - 78 - 9 - 27 - 18 - 79 - 10 - 9 - 9 - 20502
18: 9 - 9 - 18 - 9 - 9 - 9 - 9 - 27 - 18 - 78 - 9 - 27 - 18 - 78 - 9 - 9 - 9 - 20487
17: 10 - 9 - 18 - 9 - 10 - 9 - 9 - 18 - 78 - 9 - 27 - 18 - 72 - 9 - 9 - 9 - 20502
16: 9 - 10 - 9 - 9 - 9 - 9 - 18 - 79 - 9 - 27 - 18 - 78 - 9 - 9 - 9 - 20496
17: 9 - 9 - 18 - 9 - 9 - 9 - 10 - 18 - 79 - 9 - 26 - 18 - 72 - 9 - 9 - 9 - 20511
17: 9 - 9 - 18 - 9 - 10 - 9 - 9 - 18 - 78 - 9 - 27 - 18 - 78 - 9 - 9 - 9 - 20501
18: 9 - 9 - 18 - 9 - 9 - 10 - 9 - 26 - 18 - 78 - 9 - 27 - 18 - 78 - 9 - 9 - 9 - 20512
17: 9 - 9 - 18 - 9 - 9 - 9 - 9 - 18 - 78 - 9 - 27 - 18 - 79 - 10 - 9 - 9 - 20502
18: 9 - 9 - 15 - 9 - 9 - 9 - 9 - 10 - 18 - 79 - 9 - 26 - 18 - 78 - 9 - 9 - 9 - 20511
18: 9 - 9 - 9 - 9 - 9 - 9 - 9 - 26 - 18 - 72 - 9 - 27 - 18 - 79 - 10 - 9 - 9 - 20510
17: 9 - 9 - 18 - 7 - 9 - 9 - 10 - 18 - 79 - 9 - 26 - 18 - 78 - 9 - 9 - 9 - 20511
19: 9 - 9 - 18 - 10 - 9 - 9 - 9 - 9 - 27 - 18 - 78 - 9 - 27 - 18 - 78 - 9 - 9 - 9 - 20510
17: 9 - 9 - 9 - 5 - 9 - 9 - 9 - 18 - 78 - 9 - 27 - 18 - 78 - 9 - 9 - 9 - 20519
16: 9 - 9 - 18 - 9 - 9 - 9 - 9 - 18 - 78 - 9 - 18 - 79 - 9 - 9 - 9 - 20502
17: 9 - 9 - 18 - 9 - 9 - 9 - 9 - 18 - 79 - 9 - 27 - 18 - 78 - 9 - 9 - 9 - 20485
16: 9 - 9 - 9 - 9 - 10 - 9 - 18 - 78 - 9 - 27 - 18 - 78 - 9 - 9 - 9 - 20493

any ideas on can wrong this?

(why there 19 channels, why these numbers small , why changing joystick positions @ transmitter doesn't have affect on output).

i think line

code: [select]

capturing = false;
will not caught this

code: [select]

else {
    if (w > frameendthreshold) {

and consequently next not set 0

removing else may solve problem - need think carefully. , have code check long w why not there.

...r

Arduino Forum > Using Arduino > Networking, Protocols, and Devices (Moderator: fabioc84) > Weird PPM readings

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