In this example we look at the enviro:bit which is an add on from pimoroni which has a BME280 temperature, pressure, and humidity sensor fitted to it a long with a TCS3472 light and colour sensor and a MEMS microphone
Lets look at the enviro:bit fitted to a bpi:bit
enviro:bit and bpi:bit
Features:
- Comes fully-assembled and ready to use.
- BME280 temperature, pressure, and humidity sensor.
- TCS3472 light and colour sensor.
- MEMS microphone.
- Compatible with micro:bit.
- Microsoft MakeCode and MicroPython support.
- No soldering required!
Lets look at the BME280 sensor now
The BME280 is an integrated environmental sensor developed specifically for mobile applications where size and low power consumption are key design constraints. The unit combines individual high linearity, high accuracy sensors for pressure, humidity and temperature in an 8-pin metal-lid 2.5 x 2.5 x 0.93 mm³ LGA package, designed for low current consumption (3.6 μA @1Hz), long term stability and high EMC robustness.
The humidity sensor features an extremely fast response time which supports performance requirements for emerging applications such as context awareness, and high accuracy over a wide temperature range. The pressure sensor is an absolute barometric pressure sensor with features exceptionally high accuracy and resolution at very low noise. The integrated temperature sensor has been optimized for very low noise and high resolution. It is primarily used for temperature compensation of the pressure and humidity sensors, and can also be used for estimating ambient temperature.
The BME280 supports a full suite of operating modes which provides the flexibility to optimize the device for power consumption, resolution and filter performance.
Parts List
| Name | link |
| Banana PI Bit board | Banana PI Bit board with EPS32 |
| envirobit | Pimoroni enviro:bit for BBC micro:bit |
Code
You need to import the BME280 and sensor libraries into the Arduino IDE. The BME280 sensor is set to 0x76 on the envirobit
[codesyntax lang=”cpp”]
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME280.h>
#define SEALEVELPRESSURE_HPA (1013.25)
Adafruit_BME280 bme; // I2C
unsigned long delayTime;
void setup() {
Serial.begin(9600);
while(!Serial); // time to get serial running
Serial.println(F("BME280 test"));
unsigned status;
// default settings
// (you can also pass in a Wire library object like &Wire2)
status = bme.begin(0x76);
if (!status) {
Serial.println("Could not find a valid BME280 sensor, check wiring, address, sensor ID!");
Serial.print("SensorID was: 0x"); Serial.println(bme.sensorID(),16);
Serial.print(" ID of 0xFF probably means a bad address, a BMP 180 or BMP 085\n");
Serial.print(" ID of 0x56-0x58 represents a BMP 280,\n");
Serial.print(" ID of 0x60 represents a BME 280.\n");
Serial.print(" ID of 0x61 represents a BME 680.\n");
while (1);
}
Serial.println("-- Default Test --");
delayTime = 1000;
Serial.println();
}
void loop() {
printValues();
delay(delayTime);
}
void printValues() {
Serial.print("Temperature = ");
Serial.print(bme.readTemperature());
Serial.println(" *C");
Serial.print("Pressure = ");
Serial.print(bme.readPressure() / 100.0F);
Serial.println(" hPa");
Serial.print("Approx. Altitude = ");
Serial.print(bme.readAltitude(SEALEVELPRESSURE_HPA));
Serial.println(" m");
Serial.print("Humidity = ");
Serial.print(bme.readHumidity());
Serial.println(" %");
Serial.println();
}
[/codesyntax]
Output
Open the serial monitor window and you will see something like this
Temperature = 21.40 *C
Pressure = 1009.94 hPa
Approx. Altitude = 27.61 m
Humidity = 41.04 %
Temperature = 21.40 *C
Pressure = 1009.92 hPa
Approx. Altitude = 27.74 m
Humidity = 41.03 %
Temperature = 21.39 *C
Pressure = 1009.90 hPa
Approx. Altitude = 27.90 m
Humidity = 41.04 %
![](http://ae01.alicdn.com/kf/Sbf885b40323a45178795fde862d61c3cT.jpg_140x140.jpg")
