LamaPLC: BMP/BME Bosch Temperature/Humidity/Pressure sensors with I²C communication

Bosch BMP sensors primarily measure barometric pressure and temperature, while Bosch BME sensors are more comprehensive, adding humidity and, in newer models, gas/air quality sensing.

Type of measurement	Model	Power voltage	Measurement, range, accuracy	Communication	Note
Temperature Humidity Air pressure	Bosch BME280	3.3 V (1.71 .. 3.6V)	Temperature measurement range: -40 .. +80 °C Temperature measurement accuracy: ±0.5°C (-40..85) Humidity measurement range: 0..100% RH Humidity measurement accuracy: ±3% Air pressure Range: 300 .. 1100 hPa Air pressure accuracy: ±0.25%	I²C default addr.: 0x76/77 SPI	-
Temperature Humidity Air pressure	Bosch BME680	3.3 V (1.71 .. 3.6V)	Temperature measurement range: -40 .. +80 °C Temperature measurement accuracy: ±1.5°C Humidity measurement range: 0..100% RH Humidity measurement accuracy: ±3% Air pressure Range: 300 .. 1100 hPa Air pressure accuracy: ±0.25%	I²C default addr.: 0x76/77 SPI	Direct output of IAQ: Index for Air Quality
Temperature Air-pressure	Bosch BMP180	3.3 V (1.62 .. 3.6V)	Temperature measurement range: -40 .. +85 °C Temperature measurement accuracy: ±1.5°C Air pressure Range: 4.35PSI .. 15.95PSI (30kPa .. 110kPa) Air pressure accuracy: ±2%	I²C default addr.: 0x77 (fix)	Maximum Pressure: 145.04PSI (1000kPa) Temperature resolution: 0.1 °C Pressure resolution: 1 Pa
Temperature Air-pressure	Bosch BMP280	3.3 V (1.71 .. 3.6V)	Temperature measurement range: -40 .. +85 °C Temperature measurement accuracy: ±1.5°C Air pressure Range: 4.35PSI .. 15.95PSI (30kPa .. 110kPa) Air pressure accuracy: ±2%	I²C default addr.: 0x76 SPI	Maximum Pressure: 290.08PSI (2000kPa) Temperature resolution: 0.01 °C Pressure resolution: 0.16 Pa

The BME/BMP sensors can be integrated with the Tasmota system. For more details, see here:

• BMP085, BMP180 and BMP280 sensors: https://tasmota.github.io/docs/BME280/
• BME280: https://tasmota.github.io/docs/BME280/
• BME680: https://tasmota.github.io/docs/BME680/

Another name for the GY-68 module is a breakout board that integrates the Bosch BMP180 sensor to measure atmospheric pressure, temperature, and altitude. The two terms refer to different components of the same product for hobbyist use: the BMP180 is the sensing chip on the GY-68 printed-circuit board.

The GY-68 BMP180 sensor module is known for its high precision, low power consumption, and ease of use via the I2C interface, making it popular for a wide range of DIY and IoT projects.

Another name, GY-BME280, is a sensor module that integrates the Bosch BME280 environmental sensor chip and measures temperature, humidity, and atmospheric pressure. It is an upgrade to the BMP280 and is widely used in hobbyist electronics and IoT projects for comprehensive environmental monitoring.

The Bosch BME280 sensor features high precision and low power consumption, making it suitable for battery-powered systems. The GY-BME280 module often includes a voltage regulator and a logic-level converter, allowing it to operate with both 3.3V and 5V microcontrollers such as Arduino and Raspberry Pi.

*: To change the I²C address to 0x77, cut the trace between the middle and left copper pads with a sharp knife. Then add a solder blob between the middle and right copper pads to short them.

The GY-BMP280-3.3 is a sensor module featuring the Bosch BMP280 environmental sensor chip, which precisely measures atmospheric pressure and temperature. This module operates from a 3.3V DC power supply, making it a low-power solution for applications such as weather monitoring, altimetry, and navigation systems.

The Bosch BMP280 improves on its predecessors (BMP085/BMP180) by delivering better performance and lower power consumption in a smaller form factor. The GY-BMP280-3.3 module features versatile interfacing and precise measurements.

*: To set the I²C address to 0x77, connect pin 6 of the module (SDO) to Vcc, typically the 3.3V supply, and connect pin 5 of the module (CSB) to Vcc to select the I²C interface.

// include
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BMP280.h> // BMP280/HW-611
 
// variable
float bmp_280_temp;
float bmp_280_press;
bool bmp_280_ready;
String unitID = "abcd";
 
// init
Adafruit_BMP280 bmp_280; // BMP280/HW-611
 
// call block
void bmp_280_function () {
  bmp_280_temp = bmp_280.readTemperature();
  bmp_280_press = bmp_280.readPressure() / 100.0F;
  Serial.print("unitID: "); Serial.print(unitID); Serial.print("; bmp_280_temp: "); Serial.print(bmp_280_temp); Serial.println(" ; unit: C");
  Serial.print("unitID: "); Serial.print(unitID); Serial.print("; bmp_280_press: "); Serial.print(bmp_280_press); Serial.println(" ; unit: hPa");
}
 
 
void setup() {
  Serial.begin(115200);
    // unit works?
    bmp_280_ready = bmp_280.begin(0x76); 
    if (!bmp_280_ready) {
    Serial.println("BMP280/HW-611 Sensor not found");
    } else {
	Serial.println("BMP280/HW-611 Sensor works");
	}
  }
 
void loop() {
  // call all units with 2 sec raster
  static unsigned long lastTime = 0;
  if (millis() - lastTime > 2000) {
    lastTime = millis();
    // units call, if works
    if (bmp_280_ready) {bmp_280_function ();}
  }
}

The CJMCU-680 is an environmental sensor breakout board based on the Bosch BME680 chip. It is a versatile “4-in-1” module designed for DIY electronics and IoT projects.

Core Capabilities

The module measures four distinct environmental parameters:

• Temperature: Provides ambient temperature readings.
• Humidity: Measures relative humidity.
• Barometric Pressure: Can be used to calculate altitude or track weather changes.
• Gas (VOC): Features a heated metal-oxide sensor that detects Volatile Organic Compounds (VOCs) to estimate indoor air quality.

Sensor Performance

Gas Sensor Note: For accurate air quality readings, it is recommended to “burn-in” the sensor for 48 hours during the first use and allow 30 minutes of warm-up time for each subsequent session.

Response Times:

• Gas Sensor: < 1 second (τ33-63%)
• Humidity Sensor: ~8 seconds (τ0-63%)

The standard CJMCU-680 module uses the following pin arrangement:

• SCL: A5
• GND: GND
• SDA: A4
• Vdd: 3.3V (or 5V if your breakout board has a regulator).

Install the Adafruit BME680 Library (this will also prompt you to install the Adafruit Unified Sensor and Adafruit BME680 Library, which you need)

/*
 * BME680 Sensor - Arduino Uno/Nano
 * Connection: I2C
 * Data: Temperature, Humidity, Pressure, Gas (Air Quality)
 *
 * Required Libraries (Arduino Library Manager):
 *   - "Adafruit BME680 Library" by Adafruit
 *   - "Adafruit Unified Sensor" by Adafruit
 *
 * Wiring (I2C):
 *   BME680  -->  Arduino Uno/Nano
 *   VCC     -->  3.3V (or 5V depending on module)
 *   GND     -->  GND
 *   SDA     -->  A4
 *   SCL     -->  A5
 */
 
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME680.h>
 
// Sea level pressure for altitude calculation (adjust to your location in hPa!)
#define SEA_LEVEL_PRESSURE_HPA 1013.25
 
// Create BME680 object (I2C address: 0x76 or 0x77)
Adafruit_BME680 bme;
 
void setup() {
  Serial.begin(9600);
  while (!Serial);  // Wait until Serial is ready
 
  Serial.println(F("============================"));
  Serial.println(F("  BME680 Sensor - Arduino   "));
  Serial.println(F("============================"));
 
  // Initialize sensor
  if (!bme.begin(0x76)) {
    Serial.println(F("ERROR: BME680 not found!"));
    Serial.println(F("Please check your wiring."));
    Serial.println(F("Trying address 0x77 ..."));
 
    if (!bme.begin(0x77)) {
      Serial.println(F("ERROR: BME680 not found on 0x77 either!"));
      while (1); // Halt program
    }
  }
 
  Serial.println(F("BME680 found successfully!"));
 
  // Configure sensor settings
  bme.setTemperatureOversampling(BME680_OS_8X);
  bme.setHumidityOversampling(BME680_OS_2X);
  bme.setPressureOversampling(BME680_OS_4X);
  bme.setIIRFilterSize(BME680_FILTER_SIZE_3);
  bme.setGasHeater(320, 150); // Heater temperature: 320°C, Heating time: 150ms
 
  Serial.println(F("Sensor configured. Starting measurements...\n"));
  delay(2000);
}
 
void loop() {
  // Start measurement and wait for result
  if (!bme.performReading()) {
    Serial.println(F("ERROR: Reading failed!"));
    delay(2000);
    return;
  }
 
  // Print sensor values
  Serial.println(F("----------------------------"));
 
  // Temperature
  Serial.print(F("Temperature:      "));
  Serial.print(bme.temperature, 1);
  Serial.println(F(" °C"));
 
  // Humidity
  Serial.print(F("Humidity:         "));
  Serial.print(bme.humidity, 1);
  Serial.println(F(" %"));
 
  // Pressure
  Serial.print(F("Pressure:         "));
  Serial.print(bme.pressure / 100.0, 2);
  Serial.println(F(" hPa"));
 
  // Altitude above sea level (calculated)
  Serial.print(F("Altitude (approx): "));
  Serial.print(bme.readAltitude(SEA_LEVEL_PRESSURE_HPA), 1);
  Serial.println(F(" m"));
 
  // Gas resistance (air quality)
  Serial.print(F("Gas Resistance:   "));
  Serial.print(bme.gas_resistance / 1000.0, 2);
  Serial.println(F(" kΩ"));
 
  // Air quality as simple rating
  Serial.print(F("Air Quality:      "));
  Serial.println(getAirQuality(bme.gas_resistance));
 
  Serial.println();
 
  // Wait 3 seconds until next measurement
  delay(3000);
}
 
// Simple air quality rating based on gas resistance
String getAirQuality(uint32_t gasResistance) {
  uint32_t kOhm = gasResistance / 1000;
 
  if (kOhm >= 300) {
    return F("Very Good");
  } else if (kOhm >= 150) {
    return F("Good");
  } else if (kOhm >= 50) {
    return F("Moderate");
  } else if (kOhm >= 10) {
    return F("Poor");
  } else {
    return F("Very Poor");
  }
}

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