Embedded System Desgin

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 .
***********************************************************************************
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
*********************************************************************************

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

Microcontroller Based ammeter and voltmeter using Atmega 16

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.

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

ADC Reading With Internal Adc Of AVR - Atemga 32 And Displaying On LCD

Download HereADC Reading With Internal Adc Of AVR - Atemga 32 And Displaying On LCD

According to data sheet there are 3 registers are used to works the ADC in AVR atmega 32

ie ,

1) ADMUX

2)ADSCR

3)ADC

1) ADMUX :-

It is an 8 bit Register ,each bit has some functions as follows

REFS1 & REFS0 :- is used for the reference Voltage with respect to our analog input (for resolution) to know more search this blog.

I am giving 5volt as reference so selected REFS1 = 0 & REFS0 = 1

ADMUX=(1<<REFS0); // AVcc with external capacitor at AREF ,giving a high to REFS0.

MUX0-MUX4 :- it is used to select the input channel ,ie 8 analog input channel can be given so desired one selection by giving appropriate value .

ADLAR : - used to shift the resulted data (ADC Value) left or right .I am using right shift so makes as low.

.....................................................................................................................................

2) ADSCR :- ADCSRA = (1<<ADEN)|(1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0);

It is also an 8 bit register .

Bit 7 used to ADC ON (ADC Turn ONing by applying a high bit )

Bit6 ADSC is used to start the conversion .and still maintain it value as high up to the conversion . after conversion it becomes low (Zero)

ADATE and ADIF is not used by me now .(not by using Intruppet

Bit 0 to bit2 is used for select ADC frequency .

2) ADC: It is a 16 bit to 8 bit register ADCL & ADCH. By applying right shift value it is autmatically set as normal value so we can take simple value from it

eg : return (ADC);

adc_value = read_adc(ch_sec);

The program as follows . The full program can be download below including Proteus simulation file.

Full project Download here