5.1 KiB
Gateway
BLE-to-MQTT gateway running on a Raspberry Pi 4. Listens to Nordic Thingy:52 sensor nodes broadcasting environmental data over BLE and publishes it to a remote MQTT broker on each reception.
Architecture
[Thingy #1] ──┐
[Thingy #2] ──┼──(BLE)──> [Raspberry Pi / gateway.py] ──(MQTT)──> [Broker]
[Thingy #n] ──┘
The gateway listens passively to BLE advertising packets and filters on the
Nordic Configuration service UUID (ef680100). Each received packet is
decoded following the firmware key/value specification and published
immediately to the MQTT broker.
MQTT interface
Topic: {gateway_id}/{thingy_mac}/update
Example: gateway_lausanne_01/C4:64:02:60:D9:16/update
Payload:
{
"timestamp": "2026-04-08T07:53:28Z",
"temp": 25.37,
"humidity": 44,
"co2_ppm": 400,
"window_open": false
}
Fields are included only if present in the advertising packet. Values outside the valid range defined in the firmware specification indicate a failed sensor reading and are discarded.
Configuration
A config.example.json template is provided. Copy it to config.json and
edit the values before running:
{
"gateway_id": "gateway_example",
"mqtt": {
"broker": "mqtt.example.com",
"port": 8883,
"username": "your_username",
"tls": true
},
"ble": {
"service_uuid": "ef680100-9b35-4933-9b10-52ffa9740042"
}
}
Each deployed gateway has its own config.json. The source code remains
identical across all deployments.
Installation
sudo apt install -y mosquitto mosquitto-clients
sudo rfkill unblock bluetooth
sudo systemctl enable bluetooth
sudo bluetoothctl power on
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt
cp config.example.json config.json
# Edit config.json with your gateway_id, broker address and username
Usage
Set the MQTT password as an environment variable before running:
mkdir -p ~/secrets
echo "MQTT_PASSWORD=your_password" > ~/secrets/mqtt.env
chmod 600 ~/secrets/mqtt.env
export MQTT_PASSWORD="your_password"
source venv/bin/activate
python gateway.py
The password is never stored in config files or source code.
Systemd service
To run the gateway automatically on boot:
sudo cp gateway.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable gateway
sudo systemctl start gateway
Check status and logs:
sudo systemctl status gateway
sudo journalctl -u gateway -f
Deployment checklist
Follow these steps to deploy the gateway on a new Raspberry Pi.
1. Connect to the Pi
ssh pi@raspberrypi.local
2. Update the system
sudo apt update && sudo apt upgrade -y
3. Check and enable Bluetooth
sudo rfkill unblock bluetooth
sudo systemctl enable bluetooth
sudo systemctl start bluetooth
sudo bluetoothctl power on
# Expected: "Changing power on succeeded"
4. Install Mosquitto (for local testing)
sudo apt install -y mosquitto mosquitto-clients
5. Clone the repository
git clone https://github.com/PI-E2EEDA/Plein-de-eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-project.git
cd Plein-de-eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-project/gateway
6. Create Python environment
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt
7. Create configuration file
cp config.example.json config.json
nano config.json
# Set a unique gateway_id for this Pi
# Example: "gateway_id": "gateway_fribourg_01"
8. Create the secret file
mkdir -p ~/secrets
echo "MQTT_PASSWORD=your_password" > ~/secrets/mqtt.env
chmod 600 ~/secrets/mqtt.env
9. Install the systemd service
sudo cp gateway.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable gateway
sudo systemctl start gateway
10. Verify everything works
sudo systemctl status gateway
# Expected: "active (running)"
sudo journalctl -u gateway -f
# Expected: Gateway ID, MQTT connected, BLE scan started
11. Test automatic restart
sudo reboot
# After reboot, reconnect via SSH
sudo systemctl status gateway
# Expected: "active (running)" without any manual intervention
Validation checklist
active (running)in systemctl status- Correct gateway ID in logs
- MQTT connection established (
MQTT client connected) - TLS enabled (
TLS enabled) - BLE scan started (
BLE scan started) - Thingy:52 nodes detected in logs after power on
- Service restarts automatically after reboot
Notes on the CO2 sensor
The Thingy:52 embeds a CCS811 sensor which measures eCO2 — an estimated CO2 value derived from volatile organic compound (VOC) levels rather than a direct CO2 measurement. Values should be interpreted as indicative trends. The sensor requires a burn-in period of 48 hours on first use before readings stabilize.