ESP32 and SCT013 problem

who_took_my_nick · 9 March 2021 09:37

I am new with SCT013 but I managed to work with an Uno. The next step is to switch to an ESP32 for sending the data to a server. Here comes the problem.

Maybe there is some solution for this here, but I didn’t find it. So here it goes…

When I use the very bone sketch for getting the data from the CT, it works like a charm.

github.com

openenergymonitor/EmonLib/blob/master/examples/current_only/current_only.ino

// EmonLibrary examples openenergymonitor.org, Licence GNU GPL V3

#include "EmonLib.h"                   // Include Emon Library
EnergyMonitor emon1;                   // Create an instance

void setup()
{  
  Serial.begin(9600);
  
  emon1.current(1, 111.1);             // Current: input pin, calibration.
}

void loop()
{
  double Irms = emon1.calcIrms(1480);  // Calculate Irms only
  
  Serial.print(Irms*230.0);	       // Apparent power
  Serial.print(" ");
  Serial.println(Irms);		       // Irms
}

This outputs the data. I tied the CT to a pin 15, which is an analog pin on ESP32.
However, when I add the WiFi.begin(SSID, pass); in the setup function, it stops outputting the data. Is there any work arround?

Robert.Wall · 9 March 2021 13:56

I have read - I cannot remember where - that this is a known problem. It might have been here:

We generally do not recommend the ESP 32 for analogue processing, see these comments that relate particularly to noise and linearity problems.:

github.com/espressif/esp-idf

[TW#12287] ESP32 ADC accuracy

opened 09:19PM - 14 Dec 16 UTC

nassks

Type: Bug

Hi, I'm testing the ESP32's ADC on the SparkFun ESP32 Thing. Currently my me…asure seems very noisy, it constantly varies on the 5 first bits, and the zero value is around 90mV. Is there a way to achieve better accuracy? My test code : ``` adc1_config_width(ADC_WIDTH_12Bit); adc1_config_channel_atten(ADC1_CHANNEL_7, ADC_ATTEN_0db); while (true) { vTaskDelay(300 / portTICK_PERIOD_MS); printf("ADC value : %x\n", adc1_get_voltage(ADC1_CHANNEL_7)); } ``` Thank you in advance for your help.

who_took_my_nick · 10 March 2021 08:09

It says a lot.

I tried a few workarounds but not any progress.