So with a bit of research, I develop this simple code that makes exactly what I was asking here:

#include <M5Core2.h>
#define DEVICE_TIMEOUT 120000
float Time_bat = 0;

void setup{
  M5.begin();
  M5.Axp.SetBusPowerMode(1);
}

void loop{
  M5.Lcd.drawString(("Battery: " + String(M5.Axp.GetBatteryLevel())), 0, 120, 2);
  if(!M5.Axp.isVBUS() && !M5.Axp.isCharging()){
    M5.Lcd.drawString(String((millis() - Time_bat)/1000,0) + "         ", 1, 154, 1);
  }else{M5.Lcd.drawString("Feeded             ", 1, 154, 1);}

  if(!M5.Axp.isVBUS() && !M5.Axp.isCharging()){
      if(Time_bat == 0){Time_bat = millis();}
      if((millis() - Time_bat) > DEVICE_TIMEOUT){M5.shutdown();}
  }else{
    Time_bat = 0;
  } 
}

Hope it helps someone!

There are lots of ways to filter this type of data. The mean is one but you can also use median or an FIR filter. Take a look 🤗

Fábio Dias

Hello everyone,

I have some questions about powering the Core2 module:

1. Currently, if the device is turned off and is connected by USB-C, it turns on. I would like to know if I put the 5V bus in input mode and feed it 5V the same thing happens.
2. I was wondering what is the best way to detect the 5V input turning off to turn off the Core2 since there is a battery and it could stay on. Any ideas?

Thanks very much for your help!
Fábio Dias

It worked! Fixed problem eheh!

@felmue thanks for your reply again Felix,

You might just be right. Tomorrow I'll try it. Thanks a lot!

Thanks for your response @felmue,

It's very strange, that's why I'm asking on this forum. I could not find anything online. I'll take a picture of the setup, and send the relevant code.

It works well without the PmodRS232.

Code:

void setup(){
M5.begin();
M5.Rtc.begin();

// Serial Config
Serial2.begin(115200 , SERIAL_8N1, 32 , 33 );
Serial2.setTimeout(300);

// ADC Config
analogReadResolution(12);
analogSetAttenuation(ADC_11db);
pinMode(36, INPUT); // I already tried with and without this, same results
}

void loop{
M5.Lcd.drawString(("Read voltage: " + String(analogRead(36)/4095*3.9), 0, 0, 4);
}

Hi everyone,

I'm using M5Core2 to make a datalogger. For that, I'm communicating with a telemetry box by Serial using a PmodRS232, with needs alimentation. So I use PortA for Serial and feeding of PmodRS232 and the communications run smoothly.

The problem is that I'm also using PIN 36 as an ADC and if I plug the PmodRS232 at PortA the readings of the ADC increase by ~60%. If I unplug the cable of PIN 36 I get 4095 if PmodRS232 is plugged in (which is wrong), and 0, if PmodRS232 isn't plugged in (which is correct).

I already know PortA as pull-up resistors, but I don't understand why that affects PIN 36 (or 35, I already tried it) readings.

Thanks a lot for your help, I'm looking forward to solving this problem.