=== Station météo === Objectif : Construire une station météo de taille réduite (portable) et à faible coût (inférieur à 10€) donnant dans un premier temps des informations en temps réel (température, risque de pluie ...). == mesure et affichage d'une pression et d'une température == matériel provisoire : * Arduino UNO * écran http://www.electrodragon.com/product/eds-tft-lcd-lcm-spi-interface-variable1-82-2/ * capteur de pression : https://www.sparkfun.com/tutorials/253 connections : * écran : voir tutoriel * capteur : * VCC -> 3.3V * GND -> GND * SCL -> A5 * SDA -> A4 code : #include // Arduino LCD library #include #include // pin definition for the Uno #define cs 10 #define dc 9 #define rst 8 #define BMP085_ADDRESS 0x77 // I2C address of BMP085 // create an instance of the library TFT TFTscreen = TFT(cs, dc, rst); // char array to print to the screen char tempPrintout[9]; char presPrintout[12]; const unsigned char OSS = 0; // Oversampling Setting // Calibration values int ac1; int ac2; int ac3; unsigned int ac4; unsigned int ac5; unsigned int ac6; int b1; int b2; int mb; int mc; int md; // b5 is calculated in bmp085GetTemperature(...), this variable is also used in bmp085GetPressure(...) // so ...Temperature(...) must be called before ...Pressure(...). long b5; short temperature; long pressure; void setup() { Wire.begin(); bmp085Calibration(); // Put this line at the beginning of every sketch that uses the GLCD: TFTscreen.begin(); // clear the screen with a black background TFTscreen.background(0, 0, 0); // write the static text to the screen // set the font color to white TFTscreen.stroke(255, 255, 255); // set the font size TFTscreen.setTextSize(2); // write the text to the top left corner of the screen TFTscreen.text("Temperature :\n ", 0, 0); TFTscreen.text("Pression :\n ", 0, 40); // ste the font size very large for the loop TFTscreen.setTextSize(2); } void loop() { // convert the reading to a char array String sensorVal = String((float)(temperature*0.1f)); sensorVal.setCharAt(4, '\r'); sensorVal.concat(" C"); String sensorVal2 = String((float)(pressure*0.01f)); sensorVal2.concat(" hPa"); sensorVal.toCharArray(tempPrintout, 9); sensorVal2.toCharArray(presPrintout, 12); // set the font color TFTscreen.stroke(0, 255, 0); // print the sensor value TFTscreen.text(tempPrintout, 0, 20); TFTscreen.text(presPrintout, 0, 60); // wait for a moment delay(1000); temperature = bmp085GetTemperature(bmp085ReadUT()); pressure = bmp085GetPressure(bmp085ReadUP()); // erase the text you just wrote TFTscreen.stroke(0, 0, 0); TFTscreen.text(tempPrintout, 0, 20); TFTscreen.text(presPrintout, 0, 60); } void bmp085Calibration() { ac1 = bmp085ReadInt(0xAA); ac2 = bmp085ReadInt(0xAC); ac3 = bmp085ReadInt(0xAE); ac4 = bmp085ReadInt(0xB0); ac5 = bmp085ReadInt(0xB2); ac6 = bmp085ReadInt(0xB4); b1 = bmp085ReadInt(0xB6); b2 = bmp085ReadInt(0xB8); mb = bmp085ReadInt(0xBA); mc = bmp085ReadInt(0xBC); md = bmp085ReadInt(0xBE); } // Calculate temperature given ut. // Value returned will be in units of 0.1 deg C short bmp085GetTemperature(unsigned int ut) { long x1, x2; x1 = (((long)ut - (long)ac6)*(long)ac5) >> 15; x2 = ((long)mc << 11)/(x1 + md); b5 = x1 + x2; return ((b5 + 8)>>4); } // Calculate pressure given up // calibration values must be known // b5 is also required so bmp085GetTemperature(...) must be called first. // Value returned will be pressure in units of Pa. long bmp085GetPressure(unsigned long up) { long x1, x2, x3, b3, b6, p; unsigned long b4, b7; b6 = b5 - 4000; // Calculate B3 x1 = (b2 * (b6 * b6)>>12)>>11; x2 = (ac2 * b6)>>11; x3 = x1 + x2; b3 = (((((long)ac1)*4 + x3)<>2; // Calculate B4 x1 = (ac3 * b6)>>13; x2 = (b1 * ((b6 * b6)>>12))>>16; x3 = ((x1 + x2) + 2)>>2; b4 = (ac4 * (unsigned long)(x3 + 32768))>>15; b7 = ((unsigned long)(up - b3) * (50000>>OSS)); if (b7 < 0x80000000) p = (b7<<1)/b4; else p = (b7/b4)<<1; x1 = (p>>8) * (p>>8); x1 = (x1 * 3038)>>16; x2 = (-7357 * p)>>16; p += (x1 + x2 + 3791)>>4; return p; } // Read 1 byte from the BMP085 at 'address' char bmp085Read(unsigned char address) { unsigned char data; Wire.beginTransmission(BMP085_ADDRESS); Wire.write(address); Wire.endTransmission(); Wire.requestFrom(BMP085_ADDRESS, 1); while(!Wire.available()) ; return Wire.read(); } // Read 2 bytes from the BMP085 // First byte will be from 'address' // Second byte will be from 'address'+1 int bmp085ReadInt(unsigned char address) { unsigned char msb, lsb; Wire.beginTransmission(BMP085_ADDRESS); Wire.write(address); Wire.endTransmission(); Wire.requestFrom(BMP085_ADDRESS, 2); while(Wire.available()<2) ; msb = Wire.read(); lsb = Wire.read(); return (int) msb<<8 | lsb; } // Read the uncompensated temperature value unsigned int bmp085ReadUT() { unsigned int ut; // Write 0x2E into Register 0xF4 // This requests a temperature reading Wire.beginTransmission(BMP085_ADDRESS); Wire.write(0xF4); Wire.write(0x2E); Wire.endTransmission(); // Wait at least 4.5ms delay(5); // Read two bytes from registers 0xF6 and 0xF7 ut = bmp085ReadInt(0xF6); return ut; } // Read the uncompensated pressure value unsigned long bmp085ReadUP() { unsigned char msb, lsb, xlsb; unsigned long up = 0; // Write 0x34+(OSS<<6) into register 0xF4 // Request a pressure reading w/ oversampling setting Wire.beginTransmission(BMP085_ADDRESS); Wire.write(0xF4); Wire.write(0x34 + (OSS<<6)); Wire.endTransmission(); // Wait for conversion, delay time dependent on OSS delay(2 + (3<> (8-OSS); return up; }