ESP32 Forum

$ 1 0.000005 9.78399845368213 59 5 43
v -64 176 -64 240 0 1 50 9 0 0 0.5
d -32 176 80 176 2 1N4004
w -64 176 -32 176 0
r 96 176 224 176 0 1000
w 80 176 96 176 0
w 224 400 -64 400 0
w -64 240 -64 400 0
g 320 368 320 400 0
162 256 352 256 384 2 default-led 0 1 0 0.002
407 224 224 336 224 1
w 320 256 320 288 0
w 224 256 224 400 0
R 320 160 288 160 0 0 40 3.3 0 0 0.5
w 320 176 320 160 0
r 320 176 320 224 0 10000
w 432 288 432 224 0
403 496 176 736 288 0 0_64_0_21259_20_0.0125_0_2_0_3
w 320 224 432 224 2
403 496 320 736 432 0 17_64_0_21003_5_0.00009765625_0_2_17_3
w 320 288 320 368 0
x 259 436 355 439 6 12 Ground\sOf\sESP32
x 405 312 462 315 6 16 GPIO34
p 80 208 80 288 1 0 0
w 80 288 192 288 0
w 192 288 192 256 0
w 192 256 224 256 0
w 80 208 192 208 0
w 192 208 192 224 0
w 192 224 224 224 0
w 224 176 224 224 0

int count = 0;
unsigned long lastEntry;
int stat = 0;


#define INPUTPIN A0


void setup() 
{

  Serial.begin(115200);
  pinMode(INPUTPIN, INPUT);
  
  //Serial.printf("ESP TIMER : %jd \n", esp_timer_get_time());
}

void loop() 
{

  count = 0;
  lastEntry = millis();
  while (millis() < lastEntry + 1000) 
  {

    bool inputSignal = (digitalRead(INPUTPIN));
    switch (stat) 
    {
      case 0:
        if (inputSignal) 
        {
          count++;
          stat = 1;
        }
        break;

      case 1:
        if (!inputSignal) 
          stat = 0;
        break;

      default: 
        break;
    }
  }
  Serial.print("Frequency : ");
  Serial.println(count);

  
}

ESP_Sprite wrote: ↑

Thu Sep 03, 2020 7:18 am

Could be that the issue is that you're naively assuming that you're the only thing running on an ESP32... while in reality, you also have the OS, WiFi stack, BT stack, NVM, whatever that all can interrupt your task and make you detect the edge too late. Suggest you use a hardware peripheral (e.g. RMT) to do it instead.

Agree007 wrote: ↑

Thu Sep 03, 2020 12:42 pm

If this statement:

//
I got One ESP32 to produce a Square wave and send that through 1 wire to another ESP32 that reads the pulses ,
everything worked perfectly and it was so stable , but once we connect mains power .. we get those erratic readings
//

Then your problem is with your power circuit and not with the esp32. How did you powered the esp32 when it worked perfect ?

Make sure you have solid ground, eliminate noice and supply the current required by the esp32.