Alexandru Albul Albul / Mbed 2 deprecated mbed1768FinalProject

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Dependencies:   mbed MbedJSONValue HTTPClient TFT_fonts SPI_TFT_ILI9341 mbed-rtos picojsontest NTPClient SDFileSystem EthernetInterface DHT Stepper_Motor_X27168

Dht11.cpp@4:1eea5edaffc4, 2019-05-01 (annotated)

Committer:
aalbul3
Date:
Wed May 01 04:11:18 2019 +0000
Revision:
4:1eea5edaffc4
This is a test

Who changed what in which revision?

UserRevisionLine numberNew contents of line
aalbul3 4:1eea5edaffc4 1 #include "Dht11.h"
aalbul3 4:1eea5edaffc4 2
aalbul3 4:1eea5edaffc4 3 Dht11::Dht11(PinName const &p) : _pin(p) {
aalbul3 4:1eea5edaffc4 4 // Set creation time so we can make
aalbul3 4:1eea5edaffc4 5 // sure we pause at least 1 second for
aalbul3 4:1eea5edaffc4 6 // startup.
aalbul3 4:1eea5edaffc4 7 _timer.start();
aalbul3 4:1eea5edaffc4 8
aalbul3 4:1eea5edaffc4 9 _temperature = 0;
aalbul3 4:1eea5edaffc4 10 _humidity = 0;
aalbul3 4:1eea5edaffc4 11 }
aalbul3 4:1eea5edaffc4 12
aalbul3 4:1eea5edaffc4 13 int Dht11::read()
aalbul3 4:1eea5edaffc4 14 {
aalbul3 4:1eea5edaffc4 15 // BUFFER TO RECEIVE
aalbul3 4:1eea5edaffc4 16 uint8_t bits[5];
aalbul3 4:1eea5edaffc4 17 uint8_t cnt = 7;
aalbul3 4:1eea5edaffc4 18 uint8_t idx = 0;
aalbul3 4:1eea5edaffc4 19
aalbul3 4:1eea5edaffc4 20 // EMPTY BUFFER
aalbul3 4:1eea5edaffc4 21 for (int i=0; i< 5; i++) bits[i] = 0;
aalbul3 4:1eea5edaffc4 22
aalbul3 4:1eea5edaffc4 23 // Verify sensor settled after boot
aalbul3 4:1eea5edaffc4 24 while(_timer.read_ms() < 1500) {}
aalbul3 4:1eea5edaffc4 25 _timer.stop();
aalbul3 4:1eea5edaffc4 26
aalbul3 4:1eea5edaffc4 27 // Notify it we are ready to read
aalbul3 4:1eea5edaffc4 28 _pin.output();
aalbul3 4:1eea5edaffc4 29 _pin = 0;
aalbul3 4:1eea5edaffc4 30 wait_ms(18);
aalbul3 4:1eea5edaffc4 31 _pin = 1;
aalbul3 4:1eea5edaffc4 32 wait_us(40);
aalbul3 4:1eea5edaffc4 33 _pin.input();
aalbul3 4:1eea5edaffc4 34
aalbul3 4:1eea5edaffc4 35 // ACKNOWLEDGE or TIMEOUT
aalbul3 4:1eea5edaffc4 36 unsigned int loopCnt = 10000;
aalbul3 4:1eea5edaffc4 37 while(_pin == 0)
aalbul3 4:1eea5edaffc4 38 if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT;
aalbul3 4:1eea5edaffc4 39
aalbul3 4:1eea5edaffc4 40 loopCnt = 10000;
aalbul3 4:1eea5edaffc4 41 while(_pin == 1)
aalbul3 4:1eea5edaffc4 42 if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT;
aalbul3 4:1eea5edaffc4 43
aalbul3 4:1eea5edaffc4 44 // READ OUTPUT - 40 BITS => 5 BYTES or TIMEOUT
aalbul3 4:1eea5edaffc4 45 for (int i=0; i<40; i++)
aalbul3 4:1eea5edaffc4 46 {
aalbul3 4:1eea5edaffc4 47 loopCnt = 10000;
aalbul3 4:1eea5edaffc4 48 while(_pin == 0)
aalbul3 4:1eea5edaffc4 49 if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT;
aalbul3 4:1eea5edaffc4 50
aalbul3 4:1eea5edaffc4 51 //unsigned long t = micros();
aalbul3 4:1eea5edaffc4 52 Timer t;
aalbul3 4:1eea5edaffc4 53 t. start();
aalbul3 4:1eea5edaffc4 54
aalbul3 4:1eea5edaffc4 55 loopCnt = 10000;
aalbul3 4:1eea5edaffc4 56 while(_pin == 1)
aalbul3 4:1eea5edaffc4 57 if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT;
aalbul3 4:1eea5edaffc4 58
aalbul3 4:1eea5edaffc4 59 if (t.read_us() > 40) bits[idx] |= (1 << cnt);
aalbul3 4:1eea5edaffc4 60 if (cnt == 0) // next byte?
aalbul3 4:1eea5edaffc4 61 {
aalbul3 4:1eea5edaffc4 62 cnt = 7; // restart at MSB
aalbul3 4:1eea5edaffc4 63 idx++; // next byte!
aalbul3 4:1eea5edaffc4 64 }
aalbul3 4:1eea5edaffc4 65 else cnt--;
aalbul3 4:1eea5edaffc4 66 }
aalbul3 4:1eea5edaffc4 67
aalbul3 4:1eea5edaffc4 68 // WRITE TO RIGHT VARS
aalbul3 4:1eea5edaffc4 69 // as bits[1] and bits[3] are allways zero they are omitted in formulas.
aalbul3 4:1eea5edaffc4 70 _humidity = bits[0];
aalbul3 4:1eea5edaffc4 71 _temperature = bits[2];
aalbul3 4:1eea5edaffc4 72
aalbul3 4:1eea5edaffc4 73 uint8_t sum = bits[0] + bits[2];
aalbul3 4:1eea5edaffc4 74
aalbul3 4:1eea5edaffc4 75 if (bits[4] != sum) return DHTLIB_ERROR_CHECKSUM;
aalbul3 4:1eea5edaffc4 76 return DHTLIB_OK;
aalbul3 4:1eea5edaffc4 77 }
aalbul3 4:1eea5edaffc4 78
aalbul3 4:1eea5edaffc4 79 float Dht11::getFahrenheit() {
aalbul3 4:1eea5edaffc4 80 return((_temperature * 1.8) + 32);
aalbul3 4:1eea5edaffc4 81 }
aalbul3 4:1eea5edaffc4 82
aalbul3 4:1eea5edaffc4 83 int Dht11::getCelsius() {
aalbul3 4:1eea5edaffc4 84 return(_temperature);
aalbul3 4:1eea5edaffc4 85 }
aalbul3 4:1eea5edaffc4 86
aalbul3 4:1eea5edaffc4 87 int Dht11::getHumidity() {
aalbul3 4:1eea5edaffc4 88 return(_humidity);
aalbul3 4:1eea5edaffc4 89 }