Adatgy2015 / Mbed 2 deprecated DHT11_EEPROM

DHT11 and EEPROM together

Dependencies:   mbed

main.cpp@0:8253de48776b, 2016-01-13 (annotated)

Committer:
kaliczp
Date:
Wed Jan 13 12:52:35 2016 +0000
Revision:
0:8253de48776b
DHT11 and I2C EEPROM together

Who changed what in which revision?

UserRevisionLine numberNew contents of line
kaliczp 0:8253de48776b 1 #include "mbed.h"
kaliczp 0:8253de48776b 2
kaliczp 0:8253de48776b 3 #define EEPROM_ADDR (0b10100000) // EEPROM address
kaliczp 0:8253de48776b 4
kaliczp 0:8253de48776b 5 I2C i2c(I2C_SDA, I2C_SCL);
kaliczp 0:8253de48776b 6 DigitalOut myled(LED1); // Activate LED
kaliczp 0:8253de48776b 7 DigitalIn mybutton(USER_BUTTON); // Activate button
kaliczp 0:8253de48776b 8 DigitalInOut data_pin(A0); // Activate digital in
kaliczp 0:8253de48776b 9 Serial pc(SERIAL_TX, SERIAL_RX); // Initialize UART connection
kaliczp 0:8253de48776b 10 // Use a terminal program (eg. putty).
kaliczp 0:8253de48776b 11 Timer tmr; //initialize timer
kaliczp 0:8253de48776b 12 uint64_t adat; // 64 bit variable for temporary data
kaliczp 0:8253de48776b 13 int i;
kaliczp 0:8253de48776b 14 char data_write[4]; //Array for address and data
kaliczp 0:8253de48776b 15 char eeprom_read_address[2] = {0, 0};
kaliczp 0:8253de48776b 16 char data_read[2];
kaliczp 0:8253de48776b 17
kaliczp 0:8253de48776b 18 // Function to initialize DHT11
kaliczp 0:8253de48776b 19 void dht_read(void)
kaliczp 0:8253de48776b 20 {
kaliczp 0:8253de48776b 21 data_pin.output(); // Set A0 as output
kaliczp 0:8253de48776b 22 // Initialize measurement > 18 ms low
kaliczp 0:8253de48776b 23 data_pin = 0;
kaliczp 0:8253de48776b 24 wait_ms(20);
kaliczp 0:8253de48776b 25 // After high and release the pin switch input mode
kaliczp 0:8253de48776b 26 data_pin = 1;
kaliczp 0:8253de48776b 27 data_pin.input();
kaliczp 0:8253de48776b 28 // Wait until the end of 80 us low
kaliczp 0:8253de48776b 29 while(!data_pin.read()) {}
kaliczp 0:8253de48776b 30 // Wait until end of 80 us high
kaliczp 0:8253de48776b 31 while(data_pin.read()) {}
kaliczp 0:8253de48776b 32 // 40 bit, 40 read out cycle
kaliczp 0:8253de48776b 33 for(i=0; i<40; i++) {
kaliczp 0:8253de48776b 34 adat = adat << 1; // Shift for new number
kaliczp 0:8253de48776b 35 tmr.stop(); // Stop timer if runs
kaliczp 0:8253de48776b 36 tmr.reset(); // Reset timer
kaliczp 0:8253de48776b 37 // Wait until pin
kaliczp 0:8253de48776b 38 while(!data_pin.read()) {}
kaliczp 0:8253de48776b 39 tmr.start();
kaliczp 0:8253de48776b 40 while(data_pin.read()) {}
kaliczp 0:8253de48776b 41 // If DHT11 HIGH longer than 40 micro seconds (hopefully 70 us)
kaliczp 0:8253de48776b 42 if(tmr.read_us() > 40) {
kaliczp 0:8253de48776b 43 // bit is 1
kaliczp 0:8253de48776b 44 adat++;
kaliczp 0:8253de48776b 45 }
kaliczp 0:8253de48776b 46 }
kaliczp 0:8253de48776b 47 }
kaliczp 0:8253de48776b 48
kaliczp 0:8253de48776b 49 int main()
kaliczp 0:8253de48776b 50 {
kaliczp 0:8253de48776b 51 pc.printf("Log the DHT11 temperature and humidity sensor!\n\r"); //Welcome message
kaliczp 0:8253de48776b 52 while(1) {
kaliczp 0:8253de48776b 53 if (mybutton == 0) { // Button is pressed
kaliczp 0:8253de48776b 54 pc.printf("\n\rLogged humidity and temperature:\n\r"); //Welcome message
kaliczp 0:8253de48776b 55 myled = 1; // LED is ON
kaliczp 0:8253de48776b 56 i2c.write(EEPROM_ADDR, eeprom_read_address, 2, true);
kaliczp 0:8253de48776b 57 for( i=0; i < 30; i++ ) {
kaliczp 0:8253de48776b 58 i2c.read(EEPROM_ADDR, data_read, 2);
kaliczp 0:8253de48776b 59 pc.printf("%d %d\n\r",data_read[0], data_read[1]);
kaliczp 0:8253de48776b 60 }
kaliczp 0:8253de48776b 61 wait(3); // Wait 0.2 sec till continue.
kaliczp 0:8253de48776b 62 } else {
kaliczp 0:8253de48776b 63 myled =1;
kaliczp 0:8253de48776b 64 wait(0.1);
kaliczp 0:8253de48776b 65 adat = 0; // Resed global adat variable
kaliczp 0:8253de48776b 66 dht_read(); // Call the function
kaliczp 0:8253de48776b 67 // Save data to EEPROM
kaliczp 0:8253de48776b 68 data_write[2] = (adat & 0x000000ff00000000) >> 32; // Humidity
kaliczp 0:8253de48776b 69 data_write[3] = (adat & 0x0000000000ff0000) >> 16 ; // Temperature
kaliczp 0:8253de48776b 70 i2c.write(EEPROM_ADDR, data_write, 4);
kaliczp 0:8253de48776b 71 myled = 0; // LED is OFF
kaliczp 0:8253de48776b 72 wait(1.8);
kaliczp 0:8253de48776b 73 }
kaliczp 0:8253de48776b 74 }
kaliczp 0:8253de48776b 75 }