Doma sa mi váľal barometer BME280, z ktorého sa neskôr vykľul iba BMP280 – rozdiel v tom, že BME obsahuje aj vlhkomer. To z neho robí ideálny snímač na meteostanicu, a za tú cenu kľudne aj interiérový snímač pre teplotu a vlhkosť. Z čínskych webov sa doska s BME280 dá kúpiť za cca 2€ a na výber býva model s priamou 3.3V logikou (pre Arduino Mini 3.3V, Arduino Nano, ARM verzie SAMDx alebo STM32…) alebo 5V pre staré Arduino UNO a čokoľvek s 5V IO. Rozdiel je v pridaní 2 mosfetov na zmenu logickej úrovne a malého LDO na zníženie napätia.
Ja som sa rozhodol využiť na skúšanie šuflíkové zásoby – NodeMCU ktoré stoja tiež cca 2.5€ . Programovať sa dá cez Arduino GUI. Pripojenie je úplne jednoduché – štyri vodiče. Program nevyužíva Adafruit knižnice, je použitý kód z github-u, a kód webservra je úplne základný príklad. Inšpirácia z embedded-lab.

Program sa pripojí na definovanú WiFi sieť, spustí webserver a čaká na klienta. Popri tom každých 5 sekúnd spustí meranie a vypočítava plávajúci priemer tlaku, aby sa „vyhladilo“ meranie. Klientovi zobrazí webstránku, ktorá sa každých 15 sekúnd obnovuje.
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#include <Wire.h> #include <Average.h> #include <ESP8266WiFi.h> #define BME280_ADDRESS 0x76 #define alt 141 unsigned long int hum_raw,temp_raw,pres_raw; signed long int t_fine; uint16_t dig_T1; int16_t dig_T2; int16_t dig_T3; uint16_t dig_P1; int16_t dig_P2; int16_t dig_P3; int16_t dig_P4; int16_t dig_P5; int16_t dig_P6; int16_t dig_P7; int16_t dig_P8; int16_t dig_P9; int8_t dig_H1; int16_t dig_H2; int8_t dig_H3; int16_t dig_H4; int16_t dig_H5; int8_t dig_H6; const char* ssid = "mojawifi-SSID"; const char* password = "moje_heslo"; unsigned long tm = 0; double temp_act = 0.0, press_act = 0.0,hum_act=0.0; signed long int temp_cal; unsigned long int press_cal,hum_cal; // Web Server on port 80 WiFiServer server(80); Average<float> pressure_average(5); // only runs once on boot void setup() { Serial.begin(115200); uint8_t osrs_t = 1; //Temperature oversampling x 1 uint8_t osrs_p = 1; //Pressure oversampling x 1 uint8_t osrs_h = 1; //Humidity oversampling x 1 uint8_t mode = 3; //Normal mode uint8_t t_sb = 5; //Tstandby 1000ms uint8_t filter = 0; //Filter off uint8_t spi3w_en = 0; //3-wire SPI Disable uint8_t ctrl_meas_reg = (osrs_t << 5) | (osrs_p << 2) | mode; uint8_t config_reg = (t_sb << 5) | (filter << 2) | spi3w_en; uint8_t ctrl_hum_reg = osrs_h; Wire.begin(); writeReg(0xF2,ctrl_hum_reg); writeReg(0xF4,ctrl_meas_reg); writeReg(0xF5,config_reg); readTrim(); // Connecting to WiFi network Serial.println(); Serial.print("Connecting to "); Serial.println(ssid); WiFi.begin(ssid, password); while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); } Serial.println(""); Serial.println("WiFi connected"); // Starting the web server server.begin(); Serial.println("Web server running. Waiting for the ESP IP..."); delay(10000); // Printing the ESP IP address Serial.println(WiFi.localIP()); } // runs over and over again void loop() { if (millis() - tm > 5000){ temp_act = 0.0, press_act = 0.0,hum_act=0.0; readData(); temp_cal = calibration_T(temp_raw); press_cal = calibration_P(pres_raw); hum_cal = calibration_H(hum_raw); temp_act = (double)temp_cal / 100.0; press_act = (double)press_cal / 100.0; pressure_average.push(press_act); hum_act = (double)hum_cal / 1024.0; /*Serial.print("TEMP : "); Serial.print(temp_act); Serial.print(" DegC PRESS : "); //Serial.print(press_act); Serial.print(pressure_average.mean()); Serial.println(" hPa");*/ tm = millis(); } // Listenning for new clients WiFiClient client = server.available(); if (client) { Serial.println("New client"); // bolean to locate when the http request ends boolean blank_line = true; while (client.connected()) { if (client.available()) { char c = client.read(); if (c == '\n' && blank_line) { client.println("HTTP/1.1 200 OK"); client.println("Content-Type: text/html"); client.println("Connection: close"); client.println(); // your actual web page that displays temperature client.println("<!DOCTYPE HTML>"); client.println("<html>"); client.println("<head><META HTTP-EQUIV=\"refresh\" CONTENT=\"15\"></head>"); client.println("<body><h1>ESP8266 Weather Web Server</h1>"); client.println("<table border=\"2\" width=\"456\" cellpadding=\"10\"><tbody><tr><td>"); client.println("<h3>Temperature = "); client.println(temp_act); client.println("°C</h3><h3>Pressure = "); client.println(pressure_average.mean()); client.println("hPa (measured)</h3><h3>Pressure = "); client.println(bmp_atSealevel(pressure_average.mean())); client.println("hPa (corrected to sea level)</h3></td></tr></tbody></table></body></html>"); break; } if (c == '\n') { // when starts reading a new line blank_line = true; } else if (c != '\r') { // when finds a character on the current line blank_line = false; } } } // closing the client connection delay(1); client.stop(); Serial.println("Client disconnected."); } } void readTrim(){ uint8_t data[32],i=0; // Fix 2014/04/06 Wire.beginTransmission(BME280_ADDRESS); Wire.write(0x88); Wire.endTransmission(); Wire.requestFrom(BME280_ADDRESS,24); // Fix 2014/04/06 while(Wire.available()){ data[i] = Wire.read(); i++; } Wire.beginTransmission(BME280_ADDRESS); // Add 2014/04/06 Wire.write(0xA1); // Add 2014/04/06 Wire.endTransmission(); // Add 2014/04/06 Wire.requestFrom(BME280_ADDRESS,1); // Add 2014/04/06 data[i] = Wire.read(); // Add 2014/04/06 i++; // Add 2014/04/06 Wire.beginTransmission(BME280_ADDRESS); Wire.write(0xE1); Wire.endTransmission(); Wire.requestFrom(BME280_ADDRESS,7); // Fix 2014/04/06 while(Wire.available()){ data[i] = Wire.read(); i++; } dig_T1 = (data[1] << 8) | data[0]; dig_T2 = (data[3] << 8) | data[2]; dig_T3 = (data[5] << 8) | data[4]; dig_P1 = (data[7] << 8) | data[6]; dig_P2 = (data[9] << 8) | data[8]; dig_P3 = (data[11]<< 8) | data[10]; dig_P4 = (data[13]<< 8) | data[12]; dig_P5 = (data[15]<< 8) | data[14]; dig_P6 = (data[17]<< 8) | data[16]; dig_P7 = (data[19]<< 8) | data[18]; dig_P8 = (data[21]<< 8) | data[20]; dig_P9 = (data[23]<< 8) | data[22]; dig_H1 = data[24]; dig_H2 = (data[26]<< 8) | data[25]; dig_H3 = data[27]; dig_H4 = (data[28]<< 4) | (0x0F & data[29]); dig_H5 = (data[30] << 4) | ((data[29] >> 4) & 0x0F); // Fix 2014/04/06 dig_H6 = data[31]; // Fix 2014/04/06 } double bmp_atSealevel(double pressure){ return pressure / pow(1.0 - ((float)alt / 44330.0), 5.255); } void writeReg(uint8_t reg_address, uint8_t data){ Wire.beginTransmission(BME280_ADDRESS); Wire.write(reg_address); Wire.write(data); Wire.endTransmission(); } void readData(){ int i = 0; uint32_t data[8]; Wire.beginTransmission(BME280_ADDRESS); Wire.write(0xF7); Wire.endTransmission(); Wire.requestFrom(BME280_ADDRESS,8); while(Wire.available()){ data[i] = Wire.read(); i++; } pres_raw = (data[0] << 12) | (data[1] << 4) | (data[2] >> 4); temp_raw = (data[3] << 12) | (data[4] << 4) | (data[5] >> 4); hum_raw = (data[6] << 8) | data[7]; } signed long int calibration_T(signed long int adc_T){ signed long int var1, var2, T; var1 = ((((adc_T >> 3) - ((signed long int)dig_T1<<1))) * ((signed long int)dig_T2)) >> 11; var2 = (((((adc_T >> 4) - ((signed long int)dig_T1)) * ((adc_T>>4) - ((signed long int)dig_T1))) >> 12) * ((signed long int)dig_T3)) >> 14; t_fine = var1 + var2; T = (t_fine * 5 + 128) >> 8; return T; } unsigned long int calibration_P(signed long int adc_P){ signed long int var1, var2; unsigned long int P; var1 = (((signed long int)t_fine)>>1) - (signed long int)64000; var2 = (((var1>>2) * (var1>>2)) >> 11) * ((signed long int)dig_P6); var2 = var2 + ((var1*((signed long int)dig_P5))<<1); var2 = (var2>>2)+(((signed long int)dig_P4)<<16); var1 = (((dig_P3 * (((var1>>2)*(var1>>2)) >> 13)) >>3) + ((((signed long int)dig_P2) * var1)>>1))>>18; var1 = ((((32768+var1))*((signed long int)dig_P1))>>15); if (var1 == 0) { return 0; } P = (((unsigned long int)(((signed long int)1048576)-adc_P)-(var2>>12)))*3125; if(P<0x80000000) { P = (P << 1) / ((unsigned long int) var1); } else { P = (P / (unsigned long int)var1) * 2; } var1 = (((signed long int)dig_P9) * ((signed long int)(((P>>3) * (P>>3))>>13)))>>12; var2 = (((signed long int)(P>>2)) * ((signed long int)dig_P8))>>13; P = (unsigned long int)((signed long int)P + ((var1 + var2 + dig_P7) >> 4)); return P; } unsigned long int calibration_H(signed long int adc_H){ signed long int v_x1; v_x1 = (t_fine - ((signed long int)76800)); v_x1 = (((((adc_H << 14) -(((signed long int)dig_H4) << 20) - (((signed long int)dig_H5) * v_x1)) + ((signed long int)16384)) >> 15) * (((((((v_x1 * ((signed long int)dig_H6)) >> 10) * (((v_x1 * ((signed long int)dig_H3)) >> 11) + ((signed long int) 32768))) >> 10) + (( signed long int)2097152)) * ((signed long int) dig_H2) + 8192) >> 14)); v_x1 = (v_x1 - (((((v_x1 >> 15) * (v_x1 >> 15)) >> 7) * ((signed long int)dig_H1)) >> 4)); v_x1 = (v_x1 < 0 ? 0 : v_x1); v_x1 = (v_x1 > 419430400 ? 419430400 : v_x1); return (unsigned long int)(v_x1 >> 12); } |