Example Code for DFRduino-Voltage Display

Hardware Preparation

Software Preparation

• Development Tool: Arduino IDE (version 1.8.x or later). Download link: Arduino IDE
• Required Libraries:
  • Wire (built-in in Arduino IDE)
  • LiquidCrystal_I2C (needs to be installed)
• Library Installation Tutorial: Library Installation

Other Preparation Work

1. Stack the Power Shield onto the Arduino board.
2. Connect the I2C LCD module to the Arduino:
   • SDA pin of LCD → A4 pin of Arduino
   • SCL pin of LCD → A5 pin of Arduino
   • VCC pin of LCD → 5V pin of Arduino
   • GND pin of LCD → GND pin of Arduino
3. Set the jumpers near the Power Input socket of the Power Shield according to your power supply needs:
   • Both jumpers on left side: Only provide regulated power to the PWROUT terminal (Arduino Vin will have no voltage).
   • Top jumper on left, bottom jumper on right: Provide regulated power to PWROUT and connect Arduino Vin to the external power supply.
4. Connect the external power supply (4.5-35V) to the Power Shield's Power Input terminal.
5. Ensure all connections are secure and the power supply voltage is within the specified range (4.5-35V).

Sample Code

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,2);  // set the LCD address to 0x27 for a 16 chars and 2 line display

void setup()
{
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("www.DFRobot.com");
  lcd.setCursor(0, 1);
  lcd.print("Voltage: ");
  lcd.setCursor(13, 1);
  lcd.print("V");
}
void loop()
{
      int val;
      float temp;
      val=analogRead(0);
      temp=val/4.092;
      val=(int)temp;//
      lcd.setCursor(9, 1);
      lcd.print(temp);
/*
      lcd.print(0x30+val/100,BYTE);
      lcd.print(0x30+(val%100)/10,BYTE);
      lcd.print('.');
      lcd.print(0x30+val%10,BYTE);
*/
      delay(100);
}

Result

LCD will display the output voltage from the Power shield.

If you have a multimeter, you can easily read the output voltage through output terminal without the LCD and LCD displaying code. In other words, voltage regulation is independent. Consider it as a normal shield with function of voltage regulation.