Module introduction:
This module is designed based on the principle of resistance voltage division, which can reduce the input voltage of the terminal interface by 5 times. The Arduin analog input voltage is 5V, so the input voltage of the voltage detection module should not be greater than 5V×5=25V (if the 3.3V system is used, the input voltage should not be greater than 3.3Vx5=16.5V). Because the AVR chip used by Arduino is 10-bit AD, the analog resolution of this module is 0.00489V (5V/1023), so the voltage detection module detects the input low voltage of 0.00489V×5=0.02445V.
Parameters:
Voltage input range: DC0-25V
Voltage detection range: DC0.02445V-25V
Voltage analog resolution: 0.00489V
DC input interface: positive terminal is connected to VCC, negative terminal is connected to GND
Output interface: “+” connects to 5/3.3V, “-” connects to GND, “s” connects to AD pin of Arduin

Reference code:
#include <Wire.h>

int val11;
int val2;

void setup()
{
pinMode(LED1,OUTPUT);
Serial.begin(9600);
Serial.println(“Emartee.Com”);
Serial.println(“Voltage: “);
Serial.print(“V”);
}
void loop()
{
float temp;
val11=analogRead(1);
Temp = val11/4.092;
val11=(int)temp; //
val2=((val11%100)/10);
Serial.println(val2);
delay(1000);
}