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Nettemp + OpenMQTTGateway: fast BLE to MQTT setup

· 2 min read

Nettemp can now open up to nearby Bluetooth sensors with almost no effort. The latest nettemp_client can spin up and configure the MQTT broker, set subscriber rules, and auto-discover topics. You can then choose the hardware that listens for BLE beacons:

  • ESP32 with OpenMQTTGateway (active BLE scanning, Wi‑Fi uplink)
  • Raspberry Pi with Bluetooth running nettemp client + nettemp config (passive BLE sniffing)

Both paths deliver the same result—BLE sensor data lands in Nettemp over MQTT—the only difference is the device doing the listening.

Flashing OpenMQTTGateway on ESP32​

  1. Go to https://docs.openmqttgateway.com/upload/web-install.html
  2. Connect the ESP32 by USB.
  3. Select esp32dev-ble.
  4. Connect to the temporary Wi‑Fi SSID broadcast by the ESP32.
  5. In the installer, set Wi‑Fi credentials and the MQTT broker IP/host (must be done here; later edits are limited in 1.8.0/1.8.1).
  6. Finish the install and reboot the ESP32.

Running on Raspberry Pi​

If you already have a Pi with Bluetooth, you can keep everything on one box:

  • Start nettemp client and use nettemp config to enable the MQTT bridge and subscriber rules.
  • Let it listen passively for BLE beacons and forward readings to your Nettemp MQTT broker.

Known issues / tips​

  • Chrome flashing glitch? Restart Chrome and retry the web installer.
  • Set the MQTT server IP during the Wi‑Fi setup step—later edits are blocked in OMG 1.8.0/1.8.1.
  • In nettemp config you can auto-discover topics, and subscribe with one save.

https://github.com/1technophile/OpenMQTTGateway