Voltage Sensor Module (Up to 25V)

A simple but very useful module which uses a potential divider to reduce any input voltage by a factor of 5. This allows you to use the analogue input of a microcontroller to monitor voltages much higher than it capable of sensing.

For example with a 0V - 5V analogue input range, you are able to measure a voltage up to 25V.

This module also includes convenient screw terminals for easy and secure connection of a wire.

This module is based on a principle of resistive voltage divider design, can make the red terminal connector input voltage to 5 times smaller. Arduino analog input voltages up to 5v, the voltage detection module input voltage not greater than 5Vx5=25V (if using a 3.3V systems, input voltage not greater than 3.3Vx5=16.5V).

Arduino AVR chips have 10-bit AD, so this module simulates a resolution of 0.00489V (5V/1023), so the minimum voltage of input voltage detection module is 0.00489Vx5=0.02445V.


Specification:

• Divider ratio: 5:1
• Resistor Tolerance: 1%
• Max input voltage: 25V
• Resistor Value: 30K/7.5K Ohm

Pinout:

INPUT:

• GND –  This is where you connect the low side of the voltage you are measuring.   * Caution:  This is the same electrical point as your Arduino ground.
• VCC –  The is where you connect the high side of  the voltage you are measuring (0 - 25V)

OUTPUT:

• S:  This connects to your Arduino analog input.
• – (or minus):  This connects to your Arduino ground.
• +:  This is not connected.  It does absolutely nothing.

Voltage Sensor Module tutorial  (by HenrysBench)

The Connections

Find yourself a 9 volt battery and connect it,  your voltage sensor module and Arduino as shown below.

The Sketch

Enter the following sketch, upload it and go to town.   If you open your Arduino serial monitor you will be able to see the voltage.

/*
DC Voltmeter Using a Voltage Divider
Based on Code Created By
T.K.Hareendran
*/

int analogInput = A1;
float vout = 0.0;
float vin = 0.0;
float R1 = 30000.0; //  
float R2 = 7500.0; // 
int value = 0;
void setup(){
   pinMode(analogInput, INPUT);
   Serial.begin(9600);
   Serial.print("DC VOLTMETER");
}
void loop(){
   // read the value at analog input
   value = analogRead(analogInput);
   vout = (value * 5.0) / 1024.0; // see text
   vin = vout / (R2/(R1+R2)); 
   
Serial.print("INPUT V= ");
Serial.println(vin,2);
delay(500);
}