Pressure & Humidity Wireling Python Tutorial
This Wireling lets you measure Humidity, Pressure, Temperature, and the approximate Altitude all from the small BME280 sensor.
Bosch BME280 Sensor Specs
- Digital interface I²C (up to 3.4 MHz) and SPI (3 and 4 wire, up to 10 MHz)
- Operating range -40…+85 °C, 0…100 % rel. humidity, 300…1100 hPa
- Humidity sensor and pressure sensor can be independently enabled/ disabled
- Register and performance compatible with Bosch Sensortec BMP280 digital pressure sensor
- RoHS compliant, halogen-free, MSL1
- Pressure Sensor
- RMS Noise 0.2 Pa, Equiv. to 1.7 cm
- Offset temperature coefficient ±1.5 Pa/K, Equiv. to ±12.6 cm at 1 °C temperature change
- Humidity Sensor:
- Response time 1 s
- Accuracy tolerance ±3 % relative humidity
- Hysteresis ±1% relative humidity
- Voltage: 3.0V - 5.5V
- 1.8 µA @ 1 Hz humidity and temperature
- 2.8 µA @ 1 Hz pressure and temperature
- 3.6 µA @ 1 Hz humidity, pressure, and temperature
- 0.1 µA in sleep mode
- A5/SCL - I²C Serial Clock line
- A4/SDA - I²C Serial Data line
- 10mm x 10mm (.394 inches x .394 inches)
- Max Height (from the lower bottom of Wireling to upper top Wireling Connector): 3.70mm (0.15 inches)
- Weight: 1 gram (.04 ounces)
- Raspberry Pi and any other cables you'll need!
- Wireling Pi Hat
- (1) Wireling Cable
- Pressure & Humidity Wireling
- Python 3 (Python 2 is not supported!)
- All Python packages mentioned in the Pi Hat setup tutorial (tinycircuits-wireling, Adafruit-Blinka, adafruit-circuitpython-ads1x15, and adafruit-circuitpython-busdevice)
- BME280 Python Example
- BME280 Python package mentioned later
Plug your Wireling into the port you plan on using! The default in the included program is port 0.
If you want to use a different port, you just need to change the port value in the program mentioned later.
Install the necessary Python package:
sudo pip3 install adafruit-circuitpython-bme280
Lets look at the beginning of one of the package examples:
# Example prints the temperature, pressure, humidity, and altitude of the BME280 # sensor # Library by: Adafruit # Example modified by: Laverena Wienclaw for TinyCircuits import time import board import busio import adafruit_bme280 import tinycircuits_wireling # Enable power to pi hat and wirelings wireling = tinycircuits_wireling.Wireling() wireling.selectPort(0) # Select port (0-3) labeled on the Pi Hat # Create library object using our Bus I2C port i2c = busio.I2C(board.SCL, board.SDA) bme280 = adafruit_bme280.Adafruit_BME280_I2C(i2c) # OR create library object using our Bus SPI port #spi = busio.SPI(board.SCK, board.MOSI, board.MISO) #bme_cs = digitalio.DigitalInOut(board.D10) #bme280 = adafruit_bme280.Adafruit_BME280_SPI(spi, bme_cs) # change this to match the location's pressure (hPa) at sea level bme280.sea_level_pressure = 1013.25 while True: print("\nTemperature: %0.1f C" % bme280.temperature) print("Humidity: %0.1f %%" % bme280.humidity) print("Pressure: %0.1f hPa" % bme280.pressure) print("Altitude = %0.2f meters" % bme280.altitude) time.sleep(2)
Navigate in the terminal to the directory with the file parent to the examples folder.
After the program is running, your terminal should begin printing the sensor values:
Temperature: 30.9 C Humidity: 30.1 % Pressure: 975.0 hPa Altitude = 323.59 meters
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