Arduino Basic Voltmeter

21 Feb 2018 on Weekend Projects

How to make a simple arduino voltage meter without resistor.

Today we make a simple voltage meter with Arduino. When I testing the ESP WiFi range, I found that the wifi range too low. I need a multimeter but not found around me. I use arduino as multimeter. Open Arduino IDE Software. Write code below on your project.

float a = 4.72; // measured with DMM
void setup()
{
   Serial.begin(115200);
}
void loop()
{
   float volts = analogRead(0) * a  / 1023;
   Serial.println(volts);
   delay(1000);
}

Save and install on your arduino.

You need two M/F jumper cable. One part connect to GND other one connect A0 pin.

Open Arduino serial console. Set serial speed to 115200. You can see some parameters on console. Connect your AA or AAA battery to cables see battery voltage.

Note: Can measure up to maximum 5 volt.