Real time clock with relative humidity and temperature sensing
To see how to interface PIC18F4550 with DS1307 take a look at the following topic:
Real time clock with PIC18F4550 and DS1307 RTC
And to see how to interface PIC18F4550 with DHT22 (AM2302) take a look at this topic:
Interfacing PIC18F4550 with DHT22(AM2302-RHT03) digital humidity and temperature sensor
Required components:
- PIC18F4550 microcontroller
- DS1307 RTC
- DHT22 (AM2302 - RHT03) sensor
- 20x4 LCD display
- 3V Coin cell battery
- 32.768KHz crystal oscillator
- 2 x 10K resistors
- 4.7K resistor
- 10K Potentiometer
- 2 Buttons
- +5V Power Supply
- Protoboard
- Jumper Wires
Project circuit:
CCS C code:
// PIC18F4550 with DS1307 and DHT22 (AM2302-RHT03) CCS C code // http://ccspicc.blogspot.com/ // electronnote@gmail.com //LCD module connections #define LCD_RS_PIN PIN_D0 #define LCD_RW_PIN PIN_D1 #define LCD_ENABLE_PIN PIN_D2 #define LCD_DATA4 PIN_D3 #define LCD_DATA5 PIN_D4 #define LCD_DATA6 PIN_D5 #define LCD_DATA7 PIN_D6 //End LCD module connections #include <18F4550.h> #fuses NOMCLR INTRC_IO #use delay(clock = 8000000) #include <lcd.c> #use fast_io(B) #use I2C(master, I2C1, FAST=100000) #define DHT22_PIN PIN_B4 // Connection pin between DHT22 and mcu short button_state, Time_out; char time[] = "TIME: : : "; char calendar[] = " / /20 "; unsigned int8 second, second10, minute, minute10, hour, hour10, date, date10, month, month10, year, year10, day, i, j ; char message1[] = "Temperature: 00.0 C "; char message2[] = "Humidity : 00.0 % "; unsigned int8 T_byte1, T_byte2, RH_byte1, RH_byte2, CheckSum, time_read ; unsigned int16 Temp, RH; void ds1307_display(){ second10 = (second & 0x70) >> 4; second = second & 0x0F; minute10 = (minute & 0x70) >> 4; minute = minute & 0x0F; hour10 = (hour & 0x30) >> 4; hour = hour & 0x0F; date10 = (date & 0x30) >> 4; date = date & 0x0F; month10 = (month & 0x10) >> 4; month = month & 0x0F; year10 = (year & 0xF0) >> 4; year = year & 0x0F; time[16] = second + 48; time[15] = second10 + 48; time[13] = minute + 48; time[12] = minute10 + 48; time[10] = hour + 48; time[9] = hour10 + 48; calendar[9] = year + 48; calendar[8] = year10 + 48; calendar[4] = month + 48; calendar[3] = month10 + 48; calendar[1] = date + 48; calendar[0] = date10 + 48; lcd_gotoxy(1, 1); // Go to column 1 row 1 printf(lcd_putc, time); // Display time lcd_gotoxy(1, 2); // Go to column 1 row 2 switch(day){ case 1: lcd_putc("DATE:Sun"); break; case 2: lcd_putc("DATE:Mon"); break; case 3: lcd_putc("DATE:Tue"); break; case 4: lcd_putc("DATE:Wed"); break; case 5: lcd_putc("DATE:Thu"); break; case 6: lcd_putc("DATE:Fri"); break; case 7: lcd_putc("DATE:Sat"); break;} lcd_gotoxy(10, 2); // Go to column 10 row 2 printf(lcd_putc, calendar); // Display calendar } void ds1307_write(unsigned int8 address, data_){ i2c_start(); // Start I2C i2c_write(0xD0); // DS1307 address i2c_write(address); // Send register address i2c_write(data_); // Write data to the selected register i2c_stop(); // Stop I2C } void ds1307_read(){ i2c_start(); // Start I2C i2c_write(0xD0); // DS1307 address i2c_write(0); // Send register address i2c_start(); // Restart I2C i2c_write(0xD1); // Initialize data read second =i2c_read(1); // Read seconds from register 0 minute =i2c_read(1); // Read minuts from register 1 hour = i2c_read(1); // Read hour from register 2 day = i2c_read(1); // Read day from register 3 date = i2c_read(1); // Read date from register 4 month = i2c_read(1); // Read month from register 5 year = i2c_read(0); // Read year from register 6 i2c_stop(); // Stop I2C } int8 edit(int8 parameter, int8 xx, int8 yy){ while(TRUE){ if(input(PIN_B2)) button_state = 0; while(!input(PIN_B3)){ parameter++; if(i == 1 && parameter > 23) parameter = 0; if(i == 2 && parameter > 59) parameter = 0; if(i == 3 && parameter > 31) parameter = 1; if(i == 4 && parameter > 12) parameter = 1; if(i == 5 && parameter > 99) parameter = 0; lcd_gotoxy(xx, yy); printf(lcd_putc,"%02u", parameter); delay_ms(200);} lcd_gotoxy(xx, yy); lcd_putc(" "); j = 0; while((input(PIN_B2) || button_state) && input(PIN_B3) && j < 5){ j++; delay_ms(50);} lcd_gotoxy(xx, yy); printf(lcd_putc,"%02u", parameter); j = 0; while((input(PIN_B2) || button_state) && input(PIN_B3) && j < 5){ j++; delay_ms(50);} if(!input(PIN_B2) && !button_state){ button_state = 1; return parameter;} } } void start_signal(){ output_drive(DHT22_PIN); // Configure connection pin as output output_low(DHT22_PIN); // Connection pin output low delay_ms(25); output_high(DHT22_PIN); // Connection pin output high delay_us(30); output_float(DHT22_PIN); // Configure connection pin as input } short check_response(){ delay_us(40); if(!input(DHT22_PIN)){ // Read and test if connection pin is low delay_us(80); if(input(DHT22_PIN)){ // Read and test if connection pin is high delay_us(50); return 1; } } } unsigned int8 Read_Data(){ unsigned int8 i, k, _data = 0; // k is used to count 1 bit reading duration if(Time_out) break; for(i = 0; i < 8; i++){ k = 0; while(!input(DHT22_PIN)){ // Wait until pin goes high k++; if (k > 100) {Time_out = 1; break;} delay_us(1);} delay_us(30); if(!input(DHT22_PIN)) bit_clear(_data, (7 - i)); // Clear bit (7 - i) else{ bit_set(_data, (7 - i)); // Set bit (7 - i) while(input(DHT22_PIN)){ // Wait until pin goes low k++; if (k > 100) {Time_out = 1; break;} delay_us(1);} } } return _data; } void main(){ setup_oscillator(OSC_8MHZ); // Set internal oscillator to 8MHz setup_adc_ports(NO_ANALOGS); // Configure all AN pins as digital port_b_pullups(TRUE); // Enable PORTB pull-ups output_b(0); set_tris_b(0x0F); // Configure RB0,RB1,RB2 & RB3 as inputs lcd_init(); // Initialize LCD module lcd_putc('\f'); // LCD clear while(TRUE){ Time_out = 0; if(input(PIN_B2)) button_state = 0; if(!input(PIN_B2) && (!button_state)){ button_state = 1; // Convert BCD to decimal minute = minute + minute10 * 10; hour = hour + hour10 * 10; date = date + date10 * 10; month = month + month10 * 10; year = year + year10 * 10; // End conversion i=1; hour = edit(hour, 10, 1); i=2; minute = edit(minute, 13, 1); while(TRUE){ if(input(PIN_B2)) button_state = 0; while(!input(PIN_B3)){ day++; if(day > 7) day = 1; lcd_gotoxy(6, 2); // Go to column 6 row 2 switch(day){ case 1: lcd_putc("Sun"); break; case 2: lcd_putc("Mon"); break; case 3: lcd_putc("Tue"); break; case 4: lcd_putc("Wed"); break; case 5: lcd_putc("Thu"); break; case 6: lcd_putc("Fri"); break; case 7: lcd_putc("Sat"); break;} delay_ms(200); } lcd_gotoxy(6, 2); lcd_putc(" "); j = 0; while((input(PIN_B2)||button_state) && input(PIN_B3) && j < 5){ j++; delay_ms(50);} lcd_gotoxy(6, 2); switch(day){ case 1: lcd_putc("Sun"); break; case 2: lcd_putc("Mon"); break; case 3: lcd_putc("Tue"); break; case 4: lcd_putc("Wed"); break; case 5: lcd_putc("Thu"); break; case 6: lcd_putc("Fri"); break; case 7: lcd_putc("Sat"); break;} if(!input(PIN_B2) && (!button_state)){ button_state = 1; break;} j = 0; while((input(PIN_B2)||button_state) && input(PIN_B3) && j < 5){ j++; delay_ms(50);} } i=3; date = edit(date, 10, 2); i=4; month = edit(month, 13, 2); i=5; year = edit(year, 18, 2); // Convert decimal to BCD minute = ((minute/10) << 4) + (minute % 10); hour = ((hour/10) << 4) + (hour % 10); date = ((date/10) << 4) + (date % 10); month = ((month/10) << 4) + (month % 10); year = ((year/10) << 4) + (year % 10); // End conversion ds1307_write(1, minute); ds1307_write(2, hour); ds1307_write(3, day); ds1307_write(4, date); ds1307_write(5, month); ds1307_write(6, year); ds1307_write(0, 0); } ds1307_read(); // Read data from DS1307 RTCC ds1307_display(); // Diaplay time and calendar if(((second10 * 10+second)>time_read)||((second10 * 10+second)==0 && time_read)){ time_read = second10 * 10 + second; Start_signal(); if(check_response()){ // If there is response from sensor RH_byte1 = Read_Data(); // read RH byte1 RH_byte2 = Read_Data(); // read RH byte2 T_byte1 = Read_Data(); // read T byte1 T_byte2 = Read_Data(); // read T byte2 Checksum = Read_Data(); // read checksum if(Time_out){ // If reading takes long time lcd_gotoxy(21, 1); // Go to column 1 row 3 lcd_putc(" Time Out! "); lcd_gotoxy(21, 2); // Go to column 1 row 4 lcd_putc(" "); // Clear 4th row } else{ if(CheckSum == ((RH_Byte1 + RH_Byte2 + T_Byte1 + T_Byte2) & 0xFF)){ RH = RH_byte1; RH = (RH << 8) | RH_byte2; Temp = T_byte1; Temp = (Temp << 8) | T_byte2; if(Temp > 0X8000){ message1[12] = '-'; Temp = Temp & 0X7FFF; } else message1[12] = ' '; message1[13] = (Temp / 100) % 10 + 48; message1[14] = (Temp / 10) % 10 + 48; message1[16] = Temp % 10 + 48; message2[13] = (RH / 100) % 10 + 48; message2[14] = (RH / 10) % 10 + 48; message2[16] = RH % 10 + 48; message1[17] = 223; // Degree symbol lcd_gotoxy(21, 1); // Go to column 1 row 1 printf(lcd_putc, message1); // Display message1 lcd_gotoxy(21, 2); // Go to column 1 row 2 printf(lcd_putc, message2); // Display message2 } else{ lcd_gotoxy(21, 1); // Go to column 1 row 3 lcd_putc(" Checksum Error! "); lcd_gotoxy(21, 1); // Go to column 1 row 4 lcd_putc(" "); // Clear 4th row } } } else { lcd_gotoxy(21, 1); // Go to column 3 row 3 lcd_putc(" No response "); lcd_gotoxy(21, 2); // Go to column 1 row 4 lcd_putc(" from the sensor "); } } delay_ms(50); } }
Interfacing PIC18F4550 with DS1307 and DHT22 Project Video:
