project clarity required

[govindraj]

Dear sir;
i am doing project with atmega8 controller, when i am connecting load with controller that time not able to get proper voltage from controller , can u give proper relay connection.here i’m sending code of my project.

“”@@@
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay_basic.h>
#define F_CPU 1000000
#define Motor_ON PORTC|=(0X20)
#define Motor_OFF PORTC&~(1<<5))
void delay(unsigned char);
uint16_t ReadADC(uint8_t ch);
void InitADC();
void init_lcd();
void ioinit (void);
void lcd_cmd(unsigned char command);
void lcd_data(unsigned char data);
void adc(unsigned int values);
unsigned int CheckResetButton();
int display(uint8_t t);
uint16_t Current_MIN,Current_MAX,valueofthirtyper,sum,avg;
uint16_t adc_value1,adc_value2,arr[10];
uint8_t t,a,b,c;

void ioinit (void)
{
DDRB = 0b11111111; //Pin 27 of MCU as input
//PORTB = 0b00000000; //Enable internal pullup of pin 27
DDRC=0b00110000; //ADC input
PORTC|=0b00001000;
}
void adc(unsigned int values)
{
int h,t,o,ten;
t=(values/1000);
h=(values/100)%10;
ten=(values/10)%10;
o=(values%10);

lcd_data(t+48);
delay(1);
lcd_data(h+48);
delay(1);
lcd_data(ten+48);
delay(1);
lcd_data(o+48);
}

unsigned int CheckResetButton()
{
int i,j;
sum=0;avg=0;
for(i=0;i<10;i++)
{
arr=ReadADC(0);
sum+=arr;
//lcd_cmd(0xC0);
//adc(sum);
delay(1);
PORTC|=0x10;
delay(2);
PORTC&~(1<<4));
delay(1);
for(j=0;j<20;j++)
delay(2);

}
avg=sum/10;
//return(&avg);
}
void main()
{
Motor_OFF;
int i,value;
//DDRB=0xff;
DDRD=0xff;
//DDRC=0xff;
init_lcd();
InitADC();
ioinit ();
while(1)
{
lcd_cmd(0x80);
value=ReadADC(0);
adc(value);
if (bit_is_clear(PINC, 3))
{
Motor_OFF;
CheckResetButton();
valueofthirtyper=(avg)*0.3;
Current_MIN=(avg)-valueofthirtyper;
Current_MAX=(avg)+valueofthirtyper;
lcd_cmd(0xC0);
adc(Current_MIN);
}
if(value>Current_MIN && value<Current_MAX)
Motor_ON;
else
Motor_OFF;

}
}

void lcd_cmd(unsigned char command)

{

//Put command on the Data Bus
PORTB = command;

//Enable LCD for command writing
PORTD = 0b00010000;

//Allow delay for LCD to read the databus
delay(1);

//Disable LCD again
PORTD = 0b00000000;

//Allow some more delay
delay(1);
}

//Function for sending Data to LCD
void lcd_data(unsigned char data)
{
//Put data on Data Bus
PORTB= data;

//Set R/S (Regiter Select) to High, and Enable to High
PORTD = 0b00110000;

//Allow for delay
delay(1);

//Disable LCD again
PORTD = 0b00100000;

//Allow for some more delay
delay(1);
}

//Function to Initilise LCD
void init_lcd()
{
//Setup both lines of LCD
lcd_cmd(0x38);
//Set Cursor off – Enable LCD
lcd_cmd(0x0E);
//Clear Screen
lcd_cmd(0x01);
//Goto first position
lcd_cmd(0x80);
}

//Delay function

void delay(unsigned char dtime)
{
int i,j;
for(i=0;i<=dtime;i++)
{
for(j=0;j<1000;j++);
}}
//You can use your own delay functions and replace this delay function with your code
/*

---

*/

uint16_t ReadADC(uint8_t ch)
{
//Select ADC Channel ch must be 0-7
ch=ch&0b00000111;
ADMUX|=ch;

//Start Single conversion
ADCSRA|=(1<<ADSC);

//Wait for conversion to complete
while(!(ADCSRA & (1<<ADIF)));

//Clear ADIF by writing one to it
ADCSRA|=(1<<ADIF);

return(ADC);
}

void InitADC()
{
ADMUX=(1<<REFS0);
ADCSRA=(1<<ADEN)|(1<<ADPS2)|(ADPS1)|(ADPS0);//Enable ADC with Prescalar=Fcpu/128 // For Aref=AVcc;//Wait for conversion to complete
}
“”””@@@@.
In this code 1st 1min it will take 10 values from current sensor and it will make average.after that i’m adding and subtraction +-30% tolarance.it will check current value with that +-30%.when it goes beyond the avg+30% or lessthan avg-30% making portc 5th pin as high.that 5th pin giving to relay.while connecting in proteus i’m gettng o/p.but connecting in hardware its not giving constantly.in hardware part i connected o/p of current sensor to controller.can u tell me hw to interface load through relay and current sensor with controller.

Thank you.

[AJISH ALFRED]

Hi,

Simulators are just waste of time, if you want to try the same in real hardware.

 

Always connect a relay to a microcontroller through a driver circuit. The driver circuit can be a single transistor. Connect the output pin to the base of the transistor through a resistor of 1K and connect the relay to the collector. If it is an NPN transistor connect the other end of relay tp positove and emitter of transistor to ground.

[Author]

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