Temperature monitor with PIC16F877A, SSD1306 and DS18B20 sensor

[@ElectronicsDeveloper]

Source Code :
// SSD1306 OLED reset pin definition
#define SSD1306_RST PIN_D4

// DS18B20 Data pin is connected to pin RD5
#define DS18B20_PIN PIN_D5


#include
#fuses HS, NOWDT, NOPROTECT, NOLVP
#use delay(clock = 8MHz)
#use fast_io(B)
#use I2C(MASTER, I2C1, FAST = 400000, stream = SSD1306_STREAM) // initialize I2C

// include SSD1306 OLED driver source code
#include

// Variables declaration
int16 raw_temp;
char *temp = "000.0000 C";

char degree[] = {0, 7, 5, 7, 0}; // degree symbol custom char


int1 ds18b20_start(){
output_low(DS18B20_PIN); // Send reset pulse to the DS18B20 sensor
output_drive(DS18B20_PIN); // Configure DS18B20_PIN pin as output
delay_us(500); // Wait 500 us
output_float(DS18B20_PIN); // Configure DS18B20_PIN pin as input
delay_us(100); //wait to read the DS18B20 sensor response
if (!input(DS18B20_PIN)) {
delay_us(400); // Wait 400 us
return TRUE; // DS18B20 sensor is present
}
return FALSE;
}

void ds18b20_write_bit(int1 value){
output_low(DS18B20_PIN);
output_drive(DS18B20_PIN); // Configure DS18B20_PIN pin as output
delay_us(2); // Wait 2 us
output_bit(DS18B20_PIN, value);
delay_us(80); // Wait 80 us
output_float(DS18B20_PIN); // Configure DS18B20_PIN pin as input
delay_us(2); // Wait 2 us
}

void ds18b20_write_byte(int8 value){
int8 i;
for(i = 0; i < 8; i++)
ds18b20_write_bit(bit_test(value, i));
}

int1 ds18b20_read_bit(void) {
int1 value;
output_low(DS18B20_PIN);
output_drive(DS18B20_PIN); // Configure DS18B20_PIN pin as output
delay_us(2);
output_float(DS18B20_PIN); // Configure DS18B20_PIN pin as input
delay_us(5); // Wait 5 us
value = input(DS18B20_PIN);
delay_us(100); // Wait 100 us
return value;
}

int8 ds18b20_read_byte(void) {
int8 i, value = 0;
for(i = 0; i < 8; i++)
shift_right(&value, 1, ds18b20_read_bit());
return value;
}

int1 ds18b20_read(int16 *raw_temp_value) {
if (!ds18b20_start()) // Send start pulse
return FALSE;
ds18b20_write_byte(0xCC); // Send skip ROM command
ds18b20_write_byte(0x44); // Send start conversion command
while(ds18b20_read_byte() == 0); // Wait for conversion complete
if (!ds18b20_start()) // Send start pulse
return FALSE; // Return 0 if error
ds18b20_write_byte(0xCC); // Send skip ROM command
ds18b20_write_byte(0xBE); // Send read command
*raw_temp_value = ds18b20_read_byte(); // Read temperature LSB byte and store it on raw_temp_value LSB byte
*raw_temp_value |= (int16)(ds18b20_read_byte()) return 1
}

// main function
void main(void) {

delay_ms(1000);

// Initialize the SSD1306 OLED with an I2C addr = 0x7A (default address)
SSD1306_Init(SSD1306_SWITCHCAPVCC, SSD1306_I2C_ADDRESS);

// clear the whole display
SSD1306_ClearDisplay();

SSD1306_GotoXY(5, 2);
SSD1306_PutC("DS18B20 SENSOR");
SSD1306_GotoXY(6, 5);
SSD1306_PutC("TEMPERATURE:");

while (TRUE) {

if(ds18b20_read(&raw_temp)) {

if(raw_temp & 0x8000) { // If the temperature is negative
temp[0] = '-'; // Put minus sign (-)
raw_temp = ~raw_temp + 1; // Change temperature value to positive form
}
else {
if((raw_temp >> 4) >= 100) // If the temperatue >= 100 °C
temp[0] = '1'; // Put 1 of hundreds
else // otherwise
temp[0] = ' '; // put space ' '
}

// Put the first two digits ( for tens and ones)
temp[1] = ( (raw_temp >> 4) / 10 ) % 10 + '0'; // Put tens digit
temp[2] = (raw_temp >> 4) % 10 + '0'; // Put ones digit

// Put the 4 fraction digits (digits after the point)
// Why 625: because we're working with 12-bit resolution (default resolution)
temp[4] = ( (raw_temp & 0x0F) * 625) / 1000 + '0'; // Put thousands digit
temp[5] = (((raw_temp & 0x0F) * 625) / 100 ) % 10 + '0'; // Put hundreds digit
temp[6] = (((raw_temp & 0x0F) * 625) / 10 ) % 10 + '0'; // Put tens digit
temp[7] = ( (raw_temp & 0x0F) * 625) % 10 + '0'; // Put ones digit

SSD1306_GotoXY(6, 7);
printf(SSD1306_PutC, temp);
SSD1306_GotoXY(14, 7);
SSD1306_PutCustomC(degree); // degree symbol ( ° )
}

else {
SSD1306_GotoXY(6, 7); // Go to column 4 row 2
SSD1306_PutC(" Error! ");
}

delay_ms(1000); // Wait 1 second

}

}

[@ayushdeshpande2515]

Sir, please made a simulation project on PH sensor

[@ElectronicsDeveloper]

Ok, we are receiving lot of comments on similar project so we can publish it soon

[@mpumelelozungu5372]

is there a github link of all the files

[@noithugian494]

How can I make the text display larger?

[@ElectronicsDeveloper]

Use customised text or design library

[@smtronics]

How to solve the error for pin does not exist in child mode

[@ElectronicsDeveloper]

Make sure your circuit connection as per wiring diagram as shown