ThermoWorks Smoke X2/X4 Receiver

What it does

The ThermoWorks Smoke X2 and Smoke X4 are excellent BBQ / smoker thermometers — accurate, long RF range, long battery life, no app required. But the included receiver only shows the current probe readings. There's no way to record history, set alerts beyond the built-in alarm, or integrate with home automation.

This project turns a low-cost Heltec WiFi LoRa 32 board (~$15) into an additional, network-connected receiver that runs alongside the original Smoke X2/X4 receiver without interfering with it. All paired receivers continue to function normally.

• Built-in web UI — connect to the device and see current temperatures plus a live history graph in any browser.
• MQTT publishing — publishes JSON status messages on every base-station transmission (every 30 seconds) for use with Home Assistant or any other MQTT consumer.
• Home Assistant integration — auto-discovery via MQTT. Probe temperatures, attached/detached state, alarms, and Billows target temperature all show up as Home Assistant entities automatically.
• Standalone mode — for field use without home Wi-Fi, runs as its own access point.
• HTTP API — JSON endpoint for current state and probe history; consumable by any HTTP client.

Screenshots

How it works

Temperature readings flow via the LoRa RF signal from the Smoke X2/X4 base station to both the included receiver and to an ESP32+LoRa device. The latter publishes the data over MQTT (for Home Assistant or any other consumer) and serves it from a built-in web UI. All data is acquired, processed, and stored locally — no cloud dependency unless you choose (e.g., AWS IoT MQTT)

flowchart LR
  base <-->|LoRa RF| lora_sx12xx(SX12xx LoRa Transceiver)
  mqclient <--> mq
  mq <--> ha
  web <--> browser(Any web browser)

  subgraph ThermoWorks Smoke X2/X4
    Probes --> base(Base station) -->|LoRa RF| recv(ThermoWorks Receiver)
    Billows --> base
  end

  subgraph esp32 [ESP32+LoRa Smoke X Receiver]
    lora_sx12xx --> smoke_x_parser(Smoke X Parser)
    smoke_x_parser --> mqclient(MQTT client)
    smoke_x_parser --> web(HTTP server)
  end

  subgraph mqttb [MQTT Broker]
    mq(homeassistant topic)
  end

  subgraph Home Assistant
    mq_int
  end

  subgraph ha_dev [HA Device for X2/X4]
    e1(Binary sensor entities)
    e2(Sensor entities)
  end

  subgraph mq_int [MQTT Integration]
    ha(Auto discovery) --> e1
    ha(Auto discovery) --> e2
    ha_dev
  end
      

Compatible hardware

Any ESP32 board with a SPI-connected Semtech SX1276 or SX1262 LoRa transceiver operating in the 915 MHz ISM band will work. The supported and tested boards are:

# Heltec V2 (ESP32 + SX1276)
python -m esptool --chip esp32 -b 460800 write_flash 0x1000 smoke-x-receiver-heltec-v2.bin

# Heltec V3 or V4 (ESP32-S3 + SX1262)
python -m esptool --chip esp32s3 -b 460800 write_flash 0x0 smoke-x-receiver-heltec-v3.bin

After flashing

Wi-Fi setup via Improv-Serial (PSK networks)

After flashing, the install dialog will offer to configure Wi-Fi directly from your browser using the Improv-Serial protocol. Enter your SSID and password; the device connects without rebooting and the dialog links you straight to the device web UI. This works with WPA2 and WPA3 personal (PSK) networks only.

AP-mode fallback (enterprise networks or skipped setup)

If your network uses WPA2/WPA3-Enterprise (EAP-TTLS), click Skip in the install dialog — Improv does not support enterprise credentials. The device will initialize its own Wi-Fi access point. This is also the case if you close the install dialog before completing Wi-Fi setup, you manually installed with esptool, or any time the device cannot reach its configured network. Join the device AP from your phone or laptop:

• SSID: Smoke X Receiver
• Password: The extra B is for BYOBB

Navigate to http://192.168.4.1/wlan to enter your WPA2/WPA3-PSK or WPA2/WPA3-Enterprise credentials (identity, username, password, and optionally a CA certificate).

Once connected

Once on Wi-Fi, the device:

1. Requests a DHCP address with the hostname smokex — the device IP address will be shown on the OLED display.
2. Waits for a sync transmission from a Smoke X2 / X4 base station — put the base into pairing mode and the receiver will pair on the first burst.
3. Begins receiving temperature transmissions (every ~30 s) and publishes them over MQTT (if enabled) and the web UI.

Full setup details — Smoke X pairing flow, MQTT URI / TLS configuration, Home Assistant auto-discovery setup — are in the project setup guide.