@takero
I write what happened after that.
I bought a 2.5A AC adapter. I replaced it with a 1A adapter, but it didn't work.
However, it works with power supplied from a PC.

@microdynasty
Thank you for your answer.
I saw the m5 spec says 5V @ 500mA. I used a 1A AC adapter.
Does that mean it's small?

I measured the temperature and humidity, soil temperature and soil moisture using M5stack basic, sent it with sigfox, and could see it with ambient.
Then I decided to do the same with M5stack core2.

However, in the case of basic, it worked even if it was powered by the USB of the PC or from the AC adapter, but in core2 it works only by the USB power of the PC.

Even if I supply power to core2 with an AC adapter, it does not start.

I saw an article like this:
When supplying power to core2 from AC100V, press the power button, press and hold it, press it twice, or press the reset button. However, I tried everything but it didn't work.

Does anyone know how to start up when using AC adapter power supply to core2?
I would appreciate it if you could teach me.　Thank you.

@m5stack
I supplied 5v to Ⅿ5 BASIC, but it doesn't work. Why?
I connected + 5.1v to the pin socket battery and connected -t o GND.
Is it not possible to supply power from the pin socket?

Ok.Thank you.

I bought m5stack basic and core2.
These must be powered by AA batteries.

If I connect 4 batteries, the voltage will be 6V.
Is it high as a power source for m5stack?

Will m5stack supplied with 6v break?

Thank you.

Hello.　I got Basic and Core2. I want to make a door sensor by connecting ”M5stack”, ”COM.sigfox” and a ”magnet sensor”.　 Does anyone know of a helpful sketch or program?

@zontex Thank you.
DHT, DS18B20 and Soil Moisture Sensor are not M5 products. Use Arduino.
Thank you.

Hello.
I want to connect the sensors DHT22 and DS18B20 and the capacitive soil moisture sensor to Core 2 for operation.
Below is the sketch.　However, when I wrote the sketch with the pin stuck, fatal error occurred.And after that, I couldn't write.

Core 2 has been lucky enough to come back, but it's scary.Therefore, I would like to know the GPIO that should point to the sensor. Please let me know.
Thank you.

//#include <M5Stack.h>
#include <M5Core2.h>

#include "DHT.h"  
//#define DHTPIN 13  // Basic.DHT22.
#define DHTPIN 27  // Core2.DHT22 .19.27
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

#include <OneWire.h>  //DS18B20
#include <DallasTemperature.h>  //DS18B20
//#define ONE_WIRE_BUS 0 // Basic.DS18B20. 
#define ONE_WIRE_BUS 26 // Core2.DS18B20.25.26.27
OneWire oneWire(ONE_WIRE_BUS); //　OneWire
DallasTemperature sensors(&oneWire);//  Dallas Temperature sensor

#define PinSoilMoist 35  //CapSoilMoistSensor
  const int dry = 3700;   
  const int wet = 1400; 

int inttemp , inthumid ;  
int intsoilmoist , soilval , intsoiltemp;  
float temperature, humidity, soilMoist, soilTemp;  

void getData() {
delay(2000);
dht.begin();
float temperature = dht.readTemperature();
float humidity = dht.readHumidity();
if (isnan(temperature) || isnan(humidity) ) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
}
  inttemp = int ( temperature ); 
  inthumid = int ( humidity );
  Serial.print( inttemp ); Serial.println(" *C, ");  
  Serial.print( inthumid ); Serial.println(" RH% ");

  soilMoist = analogRead(PinSoilMoist);  
  soilval = map(soilMoist, dry, wet, 0, 100); 
  if(soilval >= 99)
{
  intsoilmoist = 99;
}
else if(soilval <=20)
{
  intsoilmoist = 20;
}
else if(soilval >21 && intsoilmoist < 99)
{
  intsoilmoist = soilval ;  
}
//  Serial.print( soilMoist ); Serial.println(" Pin ");  
  Serial.print( intsoilmoist ); Serial.println(" soil% ");  
  delay(250);

  sensors.requestTemperatures();  
  float soilTemp = sensors.getTempCByIndex(0);
  intsoiltemp = int ( soilTemp );  
  Serial.print( intsoiltemp ); Serial.println(" soil*C, ");  
}

void sendSigfox() {
  String msg = String (inttemp, HEX)    
               + String (inthumid, HEX)
               + String (intsoilmoist, HEX)
               + String (intsoiltemp, HEX);

   Serial2.println("AT$SF=" + msg);
  Serial.println("AT$SF=" + msg);
}

void setup() {
  M5.begin(true, false, true);  
//  M5.Speaker.write(0); 
//  M5.Axp.SetSpkEnable(0);  

//  Serial2.begin(9600, SERIAL_8N1, 16, 17);  
  Serial2.begin(9600, SERIAL_8N1, 13, 14);  
//  Serial.begin(9600);  
}

void loop() {
  getData();
  sendSigfox();  

//  M5.Power.deepSleep(SLEEP_SEC(60*15)); 
  M5.Axp.DeepSleep(SLEEP_SEC(60*0.5)); 
}

@felmue
While I was writing to Core 2, I pressed the power button for a long time and the writing was successful.

Thank you.