Weather station

You can remotely monitor the state of temperature, humidity, air pressure in your home using this Weather station, built with Raspberry Pi 4 and sensors. Thanks to its GUI this system, you can always view the logs in the database.

Wiring up the stations components

Device	Device Pins	Raspberry Pins
BME280
	VCC	GPIO 17
	GND	GND
	SDA	SDA
	SCL	SCL
YL-83 control board
	VCC	+5V
	GND	GND
	AO	x
	DO	GPIO 18
RGB led
	Cathode	GND
	Red	GPIO 13
	Blue	GPIO 12
	Green	GPIO 19
RTC
	VCC	+3.3V
	GND	GND
	SDA	SDA
	SCL	SCL
	NC	x
EEPROM
	VCC	+5V
	GND	GND
	SDA	ID_SC
	SCL	ID_SD
	WP	GND

Database setup

For this project, I use the MongoDB cluster. It consists of several collections: "current-days", "current_weeks" and "current_months". The collection names follow Mongo convention for naming.

This current version of Viper - v.0.0 - uses only "current-days" for storing entries for the day and "current-weeks" for migrating data objects from "current-days" at 0.00hrs his every day.

The data schema has the following properties:

temperature - type Number, rounded up
humidity - type Number, rounded up
pressure - as the above
rain - type Number 1 or 0. representing true or false
created_at - timestamp

Reading sensors

BME280 uses the I^2C protocol for communication. The default address may be 0x77 or 0x76. The protocol must to be enabled on the Raspberry Pi 4. To check the used addresses, run the terminal command tools "sudo i2cdetect -y 1". You may need to install I^2C tools first.

I use the open-source Python library "bme280pi" to retrieve the sensors output.

Since this sensor sometimes may disappear from I²C addresses, it has to restart occasionally. That is why its power source is connected to a GPIO pin.

YL-83 control board returns digital output, it is connected to a GPIO pin.

Cron jobs are important for the station's functionality. To use them, add these to “crontab -e” (WITHOUT sudo):

@reboot python3 /path_to/main_weather.py

0 1 * * * sudo reboot

Web GUI

It is based on ExpressJS and HandlebarsJS. It consists of server-side services and web client. You need to start the "index.js" file with node. For the best performance, use the "nodemon” package. The "Morgan" logger logs into the terminal each request to the server, the time for the response, and the response code.

The Web GUI is not ran on the microcontroller, only the code in the directory, named "reading-sensors".