Raspberry Pi: measure humidity and temperature with DHT11 / DHT22

 // How to access GPIO registers from C-code on the Raspberry-Pi // Example program // 15-January-2012 // Dom and Gert // // Access from ARM Running Linux #define BCM2708_PERI_BASE 0x20000000 #define GPIO_BASE (BCM2708_PERI_BASE + 0x200000) /* GPIO controller */ #include <stdio.h> #include <string.h> #include <stdlib.h> #include <dirent.h> #include <fcntl.h> #include <assert.h> #include <unistd.h> #include <sys/mman.h> #include <sys/types.h> #include <sys/stat.h> #include <bcm2835.h> #include <unistd.h> #define MAXTIMINGS 100 #define DHT11 11 #define DHT22 22 #define AM2302 22 int readDHT(int type, int pin); int main(int argc, char **argv) { if (!bcm2835_init()) return 1; if (argc != 3) { printf("usage: %s [11|22|2302] GPIOpin#\n", argv[0]); printf("example: %s 2302 4 - Read from an AM2302 connected to GPIO #4\n", argv[0]); return 2; } int type = 0; if (strcmp(argv[1], "11") == 0) type = DHT11; if (strcmp(argv[1], "22") == 0) type = DHT22; if (strcmp(argv[1], "2302") == 0) type = AM2302; if (type == 0) { printf("Select 11, 22, 2303 as type!\n"); return 3; } int dhtpin = atoi(argv[2]); if (dhtpin <= 0) { printf("Please select a valid GPIO pin #\n"); return 3; } printf("Using pin #%d\n", dhtpin); readDHT(type, dhtpin); return 0; } // main int bits[250], data[100]; int bitidx = 0; int readDHT(int type, int pin) { int counter = 0; int laststate = HIGH; int j=0; int i=0; // Set GPIO pin to output bcm2835_gpio_fsel(pin, BCM2835_GPIO_FSEL_OUTP); bcm2835_gpio_write(pin, HIGH); usleep(100); bcm2835_gpio_write(pin, LOW); usleep(20000); bcm2835_gpio_fsel(pin, BCM2835_GPIO_FSEL_INPT); data[0] = data[1] = data[2] = data[3] = data[4] = 0; // read data! for (i=0; i< MAXTIMINGS; i++) { counter = 0; while ( bcm2835_gpio_lev(pin) == laststate) { counter++; nanosleep(1); // overclocking might change this? if (counter == 100) break; } laststate = bcm2835_gpio_lev(pin); if (counter == 100) break; bits[bitidx++] = counter; if ((i>3) && (i%2 == 0)) { // shove each bit into the storage bytes data[j/8] <<= 1; if (counter > 16) data[j/8] |= 1; j++; } } #ifdef DEBUG for (int i=3; i<bitidx; i+=2) { printf("bit %d: %d\n", i-3, bits[i]); printf("bit %d: %d (%d)\n", i-2, bits[i+1], bits[i+1] > 15); } #endif printf("Data (%d): 0x%x 0x%x 0x%x 0x%x 0x%x\n", j, data[0], data[1], data[2], data[3], data[4]); if ((j >= 39) && (data[4] == ((data[0] + data[1] + data[2] + data[3]) & 0xFF)) ) { // yay! if (type == DHT11) printf("Temp = %d *C, Hum = %d \%\n", data[2], data[0]); if (type == DHT22) { float f, h; h = data[0] * 256 + data[1]; printf ("%s\n",h); h /= 10; f = (data[2] & 0x7F)* 256 + data[3]; f /= 10.0; if (data[2] & 0x80) f *= -1; printf("Temp = %.1f *C, Hum = %.1f \%\n", f, h); } return 1; } return 0; } 

 <?php ini_set("include_path",get_include_path().':/home/pi/dht/library'); require_once 'Zend/Loader.php'; Zend_Loader::loadClass('Zend_Gdata_Spreadsheets'); Zend_Loader::loadClass('Zend_Gdata_ClientLogin'); define('GDATA_USER','googleusername'); define('GDATA_PASSWORD','google user password'); define('GDATA_SPREADSHEET_KEY','spreadsheetkey from url'); define('GDATA_WORKSHEET_ID','od6'); try { $t = new Temperature_DHT(); // get data from sensor $data = $t->getData(11,4); $service = Zend_Gdata_Spreadsheets::AUTH_SERVICE_NAME; $client = Zend_Gdata_ClientLogin::getHttpClient(GDATA_USER, GDATA_PASSWORD, $service); $service = new Zend_Gdata_Spreadsheets($client); // add row to spreadsheet $row = array( 'datetime'=>date("Ymd H:i:s"), 'temperature'=>$data[0], 'humidity'=>$data[1], ); $service->insertRow($row, GDATA_SPREADSHEET_KEY, GDATA_WORKSHEET_ID); } catch (Exception $e) { die( $e->getMessage() ); } class Temperature_DHT { private $_maxFailCount=5; public function getData($type, $pin) { $count = 0; while ($count<=$this->_maxFailCount) { $count++; $filename = '/home/pi/dht/readDHT'; $out = exec ("$filename $type $pin"); if(preg_match("'^Temp = ([0-9\.]+) \*C, Hum = ([0-9\.]+) %'", $out,$result)) { return array($result[1],$result[2]); } } } }