BME280 - Dashboard (Express + Vue)

School project we've done using a Raspberry PI 4 with a Grove PI and the Grove BME280 I2C sensor.

Installation

If you want to use our dashboard, you can build it on your hardware.

Prerequisites

• Raspberry PI
• BME280
• Node.js ≥ 14
• Yarn (1.x)

You also need to know your BME280 sensor adresss and the bus it is connected to. Check also that your user is in the i2c group and I2C are enabled.

To get the bus number where the sensor is connected, use i2cdetect -l (sudo apt-get install i2c-tools) and you'll get a list of I2C busses available.

You can know the BME280 address by using i2cdetect -y [BUS_NUMBER].

For us the value is 76 (so 0x76), but it can be 0x77 depending on the models.

Deploy

Clone this repository and CD into it.

git clone https://github.com/MilesCodeIt/bme280-dashboard
cd bme280-dashboard

Then install the dependencies.

# Install dependencies for the root, api and dashboard.
yarn && \
cd dashboard && yarn && cd .. && \
cd api && yarn && cd ..

Run the build script.

yarn build

Finally, start the server !

yarn start --port 8080 --bus-number 1 --bme280-address 118 --sql-file ./data.sqlite

• --port
  • Type: number.
  • Defaults to 8080.
• --bus-number
  • Type: number.
  • Defaults to 1.
• --bme280-address
  • Type: number.
  • Defaults to 118 (so 0x76 in hexadecimal).
• --sql-file
  • Type: string (path).
  • Defaults to path.join(process.cwd(), "./sensor_data.db").

Now navigate to port 8080 (or --port value) and you'll see the dashboard.

API

GET /api

Shows informations about the instance.

GET /api/data[?from=<FROM>&to=<TO>]

Gives data from the database.

When from and to parameters aren't given, it will return ALL the rows of the database.

from and to values are datetimes in UNIX epoch. You can get the current timestamp in JS with Date.now(). You can use (new Date()).getTime() to get timestamp from a specific date.

WS /api/ws

Returns a WebSocket connection.

When the connection is openned, a message is sended. It should look like this.

On connection response

{
  "t": 0,
  "d": 1
}

t means type and d means data.

Every responses

t - Type	d - Data
0 - Hello (on open)	1 for success
1 - Update (database)	{ "t": number, "p": number, "h": number } where t is temperature, p is pressure and h is humidity.

Credits

Thanks you...

• i2c-bus for accessing I2C from Node.
• bme280. Most of the code for the sensor comes from here.
• Our school, Lycée Turgot, to make us do this project.