--- title: "eBUS Adapter Shield C6 Stick" description: "eBUS Adapter Shield C6 Stick connected to TapHome via MQTT. Monitors adapter health — eBUS signal, ebusd daemon status, onboard temperature and uptime." url: "https://taphome.com/en/compatibility/ebus-adapter-shield-c6-stick/" language: en lastmod: 2026-11-04 generator: hugo ai: topics: ["mqtt","gateway","ebus","heating-system","adapter-monitoring"] questions: ["How to integrate eBUS Adapter Shield C6 Stick with TapHome?","What does the eBUS Adapter Shield C6 Stick TapHome template monitor?","How to connect eBUS Adapter to TapHome via MQTT?","How to troubleshoot eBUS signal loss in TapHome?","Can TapHome read heating system data through eBUS Adapter?"] --- # eBUS Adapter Shield C6 Stick Communication: Packet Parser → MQTT - [eBUS Adapter Shield C6 Stick Product Page](https://adapter.ebusd.eu/v5-c6/stick.en.html) - [micro-ebusd MQTT Documentation](https://token.ebusd.eu/mqtt) The eBUS Adapter Shield C6 Stick is a compact USB-stick-form-factor bridge (42x16mm) that connects eBUS heating bus systems to IP networks. Built around the ESP32-C6, it runs the integrated micro-ebusd firmware that decodes eBUS protocol and publishes data via MQTT. The TapHome template monitors the adapter stick itself — signal quality, daemon connectivity, onboard temperature, and uptime — rather than the heating system data flowing through it. The adapter supports WiFi (onboard antenna), USB-C, and optional Ethernet (USR-ES1 W5500 module). It draws less than 120mA at 5V and takes zero power from the eBUS line (Class 0, full galvanic isolation). ## Configuration ### MQTT prefix The TapHome template uses a fixed topic prefix `stick-c6/`. The adapter publishes health data to this prefix when micro-ebusd is running with MQTT enabled. If your adapter uses a different MQTT prefix, update the topic strings in the TapHome listener scripts accordingly. ### Template setup After importing the template in TapHome: 1. Open the **eBUS Adapter Shield C6 Stick** module 2. Set the **MQTT Broker IP** and **Port** (default `1883`) 3. Verify that the topic prefix in the listener scripts matches your adapter's MQTT configuration The module subscribes to the four `stick-c6/` topics and maps them to monitoring devices in TapHome. ### Adapter setup Before the TapHome template can receive data, the adapter must be configured: 1. **Flash firmware** — use the web flasher at [adapter.ebusd.eu](https://adapter.ebusd.eu/v5-c6/firmware.en.html) 2. **Connect to WiFi** — on first boot the adapter creates an AP with SSID "EBUS" (no password); connect and configure at `http://192.168.4.1` 3. **Enable micro-ebusd** — acquire a token via the adapter's Configuration tab, then select the micro-ebusd protocol option 4. **Configure MQTT** — set the MQTT broker host and port in the adapter settings 5. **Connect eBUS** — attach the 2-wire eBUS cable to the 3.5mm pluggable terminal (polarity-independent) > [!TIP] > The adapter supports WPS push-button mode for WiFi setup. Press the button once when the red LED illuminates steadily to connect automatically. ## Device capabilities ### eBUS Signal The eBUS Signal device is a Reed Contact that reports whether the adapter detects a valid eBUS signal on the bus: - `"true"` → **OK** (signal present) - `"false"` → **Alarm** (signal lost) This is the primary indicator of physical eBUS connectivity. A lost signal means the adapter is not receiving data from the heating system. ### ebusd Daemon The ebusd Daemon device is a Reed Contact that monitors whether the micro-ebusd daemon (or an external ebusd instance) is running and connected: - `"true"` → **OK** (daemon connected) - `"false"` → **Alarm** (daemon disconnected) If this shows alarm while the eBUS signal is OK, the issue is with the ebusd software rather than the physical connection. ### Temperature Sensor The onboard temperature sensor reads the ESP32-C6 chip temperature. This is the adapter's internal temperature, not a heating system temperature reading. It can be used to monitor the adapter for overheating in enclosed installations. The value is published as a numeric string on `stick-c6/temp` and converted to a double in the TapHome listener script. ### Uptime (h) The Uptime device tracks how long the adapter has been running since last reboot. The raw MQTT payload is in seconds; the TapHome listener script converts it to hours for easier reading. A sudden uptime reset to zero indicates the adapter rebooted — useful for diagnosing intermittent connectivity issues. ### Additional capabilities The adapter publishes additional MQTT topics not covered by this template: - **Error reporting** (`{prefix}/error`) — JSON payload with error source and description - **Scan status** (`{prefix}/scan`) — reports "OK", "running", or "finished" during eBUS device scanning - **Heating system data** (`{prefix}/circuit/name`) — the actual decoded eBUS readings (temperatures, pressures, operating modes) from connected heating equipment. Integrating this data into TapHome would require separate templates tailored to the specific heating system model. ## Troubleshooting ### No data in TapHome 1. Verify the adapter is connected to WiFi — check the RGB LED and green eBUS-LED for activity 2. Confirm micro-ebusd is activated and MQTT is enabled in the adapter's configuration page 3. Check that the MQTT broker address and port match between the adapter settings and TapHome module configuration 4. Use an MQTT client (e.g., MQTT Explorer) to subscribe to `stick-c6/#` and verify the adapter publishes messages ### eBUS Signal alarm 1. Check the physical eBUS cable connection at both the adapter's 3.5mm terminal and the heating system 2. Verify the green eBUS-LED — if it is off, no eBUS voltage is detected; if flashing, the adapter is receiving data 3. Ensure the eBUS line is not overloaded — the adapter is Class 0 (zero power draw) but other eBUS devices may exceed the bus capacity ### ebusd Daemon alarm with signal OK 1. If using micro-ebusd, check that the token is valid and the protocol option is selected correctly 2. If using external ebusd, verify the device string uses the enhanced mode prefix `ens:` (e.g., `ens:192.168.0.50:9999`) 3. Check ebusd logs for connection errors > [!NOTE] > This template monitors the eBUS adapter stick health only. To read actual heating system data (temperatures, operating modes, pressures), you need ebusd configured with the appropriate CSV message definitions for your heating system, and additional TapHome templates to subscribe to those topics. For the Vaillant aroTHERM plus with the sensoCOMFORT VRC 720 there is a [community template](https://taphome.com/en/compatibility/vaillant-ebus-micro-ebusd-http/) that reads the heating data over the HTTP API of micro-ebusd on this adapter. ## Available devices eBUS Adapter Shield C6 Stick Module Custom Variables eBUS Signal Reed Contact Read-only eBUS signal status — reports OK when adapter detects valid eBUS signal, alarm when signal is lost boolean string ebusd Daemon Reed Contact Read-only ebusd daemon connection status — reports OK when daemon is connected, alarm when disconnected boolean string Temperature Sensor Temperature Sensor Read-only Onboard ESP32-C6 chip temperature — monitors adapter internal temperature for overheating detection in enclosed installations numeric Unit: °C Uptime (h) Variable Read-only Adapter uptime in hours since last reboot — a sudden reset to zero indicates the adapter rebooted numeric Unit: h **Connection:** Packet Parser → MQTT Possible improvements (3) - Error Reporting — JSON payload with source and error fields. Could surface adapter/bus errors in TapHome. - Scan Status — Reports 'OK', 'running', or 'finished'. Could track eBUS scan progress. - Heating System Data — Actual heating system readings (temperatures, modes, pressures). Requires separate templates per heating system model. ## Sources - eBUS Adapter Shield C6 Stick Edition — Product Page [adapter.ebusd.eu](https://adapter.ebusd.eu/v5-c6/stick.en.html) 2026-03-15 - eBUS Adapter Shield C6 — Setup Guide [adapter.ebusd.eu](https://adapter.ebusd.eu/v5-c6/steps.en.html) 2026-03-15 - micro-ebusd MQTT Topic Documentation [token.ebusd.eu](https://token.ebusd.eu/mqtt) 2026-03-15 - ebusd MQTT Integration Wiki [github.com](https://github.com/john30/ebusd/wiki/MQTT-integration) 2026-03-15 ## Related Documentation - [MQTT Integration](https://taphome.com/en/compatibility/mqtt-guide/) - [Packet Parser (HTTP, TCP, UDP, FTP, MQTT)](https://taphome.com/en/docs/integration/packet-parser/) - [Packet parser functions](https://taphome.com/en/docs/script/packet-parser/) - [Parsing functions](https://taphome.com/en/docs/script/parsing-functions/) - [MQTT Broker](https://taphome.com/en/docs/integration/packet-parser/mqtt-broker/) - [Listener scripts](https://taphome.com/en/docs/script/listener-scripts/)