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Arduino voltmeter using an MCP3421 18 bit ∆-∑ ADC
/*
This revision includes the modified display output to the LCD
mcp adress = 0x68
sr= Sample Rate Selection
sr=0 ; 00 = 240 SPS (12 bits),
sr=1 ; 01 = 60 SPS (14 bits),
sr=2 ; 10 = 15 SPS (16 bits),
sr=3 ; 11 = 3.75 SPS (18 bits)
pga= PGA Programmable Gain Amplifier Selector
0 = 1 V/V,
1 = 2 V/V,
2 = 4 V/V,
******--MCP.init(address,sr,pga);--******
*/
#include <Wire.h>
#include "MCP3421.h"
MCP3421 MCP = MCP3421();
#include <LiquidCrystal.h>
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
//int pinVCC=17; // pin A3 used as + Powersupply for ADC
//int pinGND=16; // pin A2 used as GND Powersupply for ADC
int pinLed=13;
char st1[20];
long l1;
double vin;
float f1;
void setup(void)
{
lcd.begin(16,2);
//pinMode(pinVCC,OUTPUT); //Not Necessary unless you want to use the analog
//pinMode(pinGND,OUTPUT); //pins as a power supply output for the ADC
pinMode(pinLed,OUTPUT);
//digitalWrite(pinVCC,1); // switch on pin for MCP3421 5 volt powersupply
lcd.print("ADC MCP 3421"); // just to be sure things are working
Wire.begin();
delay(1000);
lcd.setCursor(0,1);
lcd.print("begin");
delay(2000);
lcd.clear();
MCP.init(0x68,3,0);
}
void loop(void)
{
while(MCP.ready()==0);
digitalWrite(pinLed,1);
vin=MCP.getDouble();
f1=vin;
analogRead(0);
delay(10);
int v1=analogRead(0);
int calibration=map(v1,0,1023,0,255);
float prescale=(calibration*0.01);
lcd.setCursor(1,0);
float voltage=(f1*(11+prescale));
float q=abs(voltage);
if (q>=10.0){
lcd.setCursor(2,0);
lcd.print(q,2);
}else{
lcd.setCursor(2,0);
lcd.print(q,3);
digitalWrite(pinLed,0);
delay(200);
}
//******************************************************************************************
void sprintDouble( char *str, double val, byte precision){
// prints val with number of decimal places determine by precision
// precision is a number from 0 to 6 indicating the desired decimial places
// example: lcdPrintDouble( 3.1415, 2); // prints 3.14 (two decimal places)
char st2[16];
unsigned long frac;
unsigned long mult = 1;
int mant= int(val);
byte padding = precision -1;
byte sgn=0;
sprintf(str,"");
if (val < 0) sprintf(str,"-");
mant=abs(mant);
sprintf(st2,"%d",mant); //prints the int part
strcat(str,st2);
if( precision > 0) {
strcat(str,".");
while(precision--)
mult *=10;
if(val >= 0)
frac = (val - int(val)) * mult;
else
frac = (int(val)- val ) * mult;
unsigned long frac1 = frac;
int cnt=precision;
// while( frac1 /= 10 )
while( frac1 = frac1 / 10 & cnt-- )
padding--;
while( padding--) strcat(str,"0");
sprintf(st2,"%ld",frac);
strcat(str,st2);
}
}
@wallygit

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wallygit commented Nov 1, 2013

where is the "MCP3421.h" file ?

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