Microcontroller Based ammeter and voltmeter using Atmega 16

Here  Atmega16  measuring the  current and voltage by inbuilt comparator  .Previous post described how to read ADC value click here . Two  ADC port is used  PA0/ADC0  is  measuring voltage .And PA1/ADC1 is  measuring current .

For Advancedtutorials click here Voltmeter Design

                We have to measure 0 to 12 volt, but controller can only read as maximum voltage 5 volt .
Hence a voltage divider circuit used to reduce the corresponding voltage level  at a mximum 5Volt.

take
Vin  = 12volt
Vout = 5 volt.
Assume one of the resistor value and find out the other .
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  we have to measure current ,But we cant directly measure the current . there are more technique to measure the current. we uses a shunt resistor method .

The millivoltmeter voltage is taken and calculated by some equation and displayed as current .for more click here

For example .
According Ohm's law,  0.1 Ohm resistor under 1A current will give 0.1V voltage drop
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                                             The program shown below

* Created: 14-Oct-15 6:44:15 PM
 *  Author: Gireesh 
 */ 
#define F_CPU 16000000UL
#include <avr/io.h>
#include<util/delay.h>
#include"lcd.h"
#include "adc.h"

int main(void)
  
{   
 
 unsigned char volt[5] ,current[5];
   DDRD = 0xFF;
   int v,i;
   char ch_sec =0;
    adc_init();
    lcd_init(); 
 string ("G Electron ");
 LINE2
 string("Power Supply");
 _delay_ms(50);
 CLEAR
 while(1)
 
 {
   v =   read_adc(0);  // reading voltage    
   i =   read_adc(1);  // reading voltage for current  
   v = (v * 4.89 * 2.4)/10;
   i = (i * 2.92);
   i = ((i*4.89)/0.47)/10;
   
   
      
   if(v< 1200)
   {
   volt[0] = ((v /1000)%10)+0x30;
   volt[1] = ((v /100) % 10) + 0x30;
   volt[2] = '.';
   volt[3] = ((v/ 10) %10) + 0x30;
   volt[4] = (v % 10) + 0x30 ;
   
   
   string("Volt    : ");
   for(int i =0; i<5;i++)
  lcd_data(volt[i]); // just displaying ADC value 
  string("V");
  }
  else
  {
 
   string("Over Voltage");
    }
 LINE2
 if(i<3100)
 {
 current[0] =((i /1000)%10)+0x30;
 current[1] = '.';
 current[2] = ((i /100) % 10) + 0x30;
 current[3] = ((i/ 10) %10) + 0x30;
 string("Current : ");
 for(int i =0; i<4;i++)
 lcd_data(current[i]);
 string("A");
 } 
 else
 {
  
  string("Over Current");
 }
 _delay_ms(50);
 CLEAR 
 }  
}

design circuits to feed controller for current and Volt. the whole project can be download Below including proteus file For downloading click below
      
                                                 Download