Code for power supply display

power_supply.c

/*
 * Voltage and current monitor for lab supply
 * 
 * LCD and analog input pin assignments as shown below
 * 
 * Matt Godfrey, 2015
*/

#include <LiquidCrystal.h>

int Vset = A7;
int Iset = A6;
int Vmeas = A5;
int Imeas = A4;

//               (RS, EN, D4, D5, D6, D7)
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

void setup() {
  //lcd setup
  lcd.begin(20, 4);
  lcd.clear();
  
  //ADC pin setup
  pinMode(Vset, INPUT);  
  pinMode(Vmeas, INPUT);  
  pinMode(Iset, INPUT);  
  pinMode(Imeas, INPUT);  
  analogReference(DEFAULT); //use power supply reference (5V)
}


void loop() {
  //meaure values. Note the calibration factors (5.64) which were
  //calculated by measuring the output with a multimeter
  float set_voltage = 5.64*5.0/1024.0*analogRead(Vset); 
  float meas_voltage = 5.64*5.0/1024.0*analogRead(Vmeas);
  float set_current = analogRead(Iset)*(5.0/1024.0);
  float meas_current = analogRead(Imeas)*(5.0/1024.0);

  //update the lcd
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Vmeas = ");
  lcd.setCursor(8, 0);
  lcd.print(meas_voltage);
  lcd.setCursor(0, 1);
  lcd.print("Vset = ");
  lcd.setCursor(8, 1);
  lcd.print(set_voltage);
  lcd.setCursor(0, 2);
  lcd.print("Imeas = ");
  lcd.setCursor(8, 2);
  lcd.print(meas_current);
  lcd.setCursor(0, 3);
  lcd.print("Iset = ");
  lcd.setCursor(8, 3);
  lcd.print(set_current);
  
  delay(50);  
}