HCP Bridge

HCP-Bridge – Hörmann series 4 garage doors on Wi-Fi / Loxone

⚠ Work in progress – rev 0.1 has not been manufactured or tested yet. Schematic and layout are complete and checked (ERC 0 errors, DRC 0 errors), but no board has been built or run on an operator so far. Build at your own risk; results of the first build will be added here.

A small board (one per door) that plugs into the BUS port (RJ12) of a Hörmann series 4 garage door operator (ProMatic 4, SupraMatic E/P 4). It acts as a UAP1-HCP expansion module towards the operator and exposes the door via Wi-Fi. Loxone talks to it over plain HTTP, no extra server needed (see below).

Firmware: This repository contains the hardware only. The board is meant to run the existing third-party open-source firmware HCPBridgeMqtt by Gifford47 (environment HCP_Giffordv2, provides web UI, HTTP API and MQTT). The board uses the same pins as the original ESP32-S3 boards, so the firmware runs unchanged. Please direct firmware questions to that project.

Status rev 0.1 (2026-10-14): ERC 0 errors, DRC 0 errors (4 warnings: footprint silkscreen at the board edge, trimmed by the manufacturer).

Key data

Reverse polarity and cable tolerant

RJ12 cables exist as straight and crossed versions, and the pin 1 side of the jack was derived from documentation. Reversed, +24 V would end up on GND and A/B would be swapped. Therefore:

• Power goes through a bridge rectifier (4 × Schottky): polarity does not matter and the board is not damaged either way.
• Solder jumpers A/B (JP1/JP2), default 1-2 (A = jack pin 4, B = pin 3).
• JP3 "120R" (bus termination): leave open, close only if communication is unreliable.

Setting A/B – one measurement is enough: cable and jack can only swap the wires mirrored (1↔6, 2↔5, 3↔4), so power and data always flip together. With the bridge plugged in and the operator powered, measure on the bottom side at the solder pins of the RJ12 jack J1: red probe on the pin marked "+" (pin 5, outer pin), black probe on the pin marked "−" (pin 1, outer pin on the other end):

The rule is also printed on the bottom side. Bus pinout at the operator according to HCPBridgeMqtt: 1/2 GND, 3 B−, 4 A+, 5/6 +24 V.

Folders

hardware/kicad/        KiCad 9 project HCPBridge.kicad_pro (schematic, PCB, own footprints)
hardware/fabrication/  schematic PDF, Gerber ZIP, BOM, LCSC order file, JLCPCB BOM + CPL, assembly drawing, ERC/DRC
docs/                  board render

Ordering (2 doors → 2 boards, plan a spare)

• PCB: upload hardware/fabrication/HCPBridge-gerber.zip to JLCPCB (2 layers, 1.6 mm, lead-free HASL; 5 pcs is the minimum).
• Parts: at lcsc.com open BOM Tool → Upload BOM File and upload hardware/fabrication/lcsc-order.xlsx (or lcsc-order.csv). When asked to assign the columns, choose LCSC Part Number → LCSC Part Number and Quantity → Quantity. Quantity is the quantity per board; enter the number of boards (e.g. 3 = 2 doors + 1 spare) as the order multiplier in the BOM tool. The column Total for 3 boards + spare is for checking only (it adds 5 spare pieces of each small 0603 part, which tend to get lost when hand soldering), do not assign it. LCSC rounds up to its minimum order quantities. bom.csv is the per-board list with reference designators. Solder jumpers and test points are copper only.
• JLCPCB assembly (alternative to hand soldering): upload jlcpcb-bom.csv (BOM) and jlcpcb-cpl.csv (pick and place) in the PCB assembly step. Rotations and reference points were derived from the LCSC/EasyEDA footprints. Check D8, F1, L1 and U1 in the JLC placement preview: their EasyEDA data could not be compared (pin 1 of D8/U1 must match the marking on the board). J1 (RJ12) is a through-hole part; select it only if you also order through-hole assembly.
• Optional: order a stencil from JLCPCB as well, it makes USB-C and the ESP32 module much easier.
• Cable: RJ12 6P6C cable with all 6 wires populated (many phone cables only have 4!). Straight or crossed does not matter, the solder jumpers take care of it.

Assembly and first start

1. Populate the regulator first (U1, L1, C1–C5, R1–R4, D7) and power it from USB-C: green LED on, 3.3 V across C4. Then the rest. Assembly drawing: hardware/fabrication/assembly.pdf.
2. Flash the firmware with PlatformIO (guide: flashing_instructions.md), environment HCP_Giffordv2 (ESP32-S3, TX 17 / RX 18, LED 13, PSRAM). Connect USB-C to the PC; if the ESP32 is not detected: hold BOOT, press RESET.
3. The bridge opens a hotspot; enter your Wi-Fi at http://192.168.4.1, then assign a fixed IP in your router. Set a password in the web UI (see Loxone).
4. Unplug USB, plug the bridge into the BUS port of the operator with the RJ12 cable.
5. Measure at J1 (bottom side, "+"/"−") and set the A/B jumpers accordingly (see above). Unplug the RJ12 cable before resoldering.
6. Start a bus scan on the operator (otherwise it does not see the bridge): depending on the control board via menu 37 or by switching the last DIP switch ON → OFF. Guide: bus_scan_EN.md. The door state must then show up in the web UI.

Do not connect USB (PC) and the bus at the same time if PC and operator are earthed differently.

Loxone integration (HTTP, no MQTT)

The commands are simple GET requests. With a web password set, the bridge asks for basic auth (user admin); in Loxone use the address http://admin:<password>@<ip>.

Virtual output "Garage door 1", address http://admin:<pw>@192.168.x.y, commands:

Virtual HTTP input "Garage door 1 status", URL http://admin:<pw>@192.168.x.y/status, polling every 2–5 s. Command recognition:

Gate block: set the Loxone "Gate" block to "subsequent control" and connect its outputs Op/Cl (or Tg) to the Open/Close (or Toggle) commands of the virtual output. Feedback comes from the HTTP input: end position open = state 0, end position closed = state 2, the position directly from currentPosition / 100. The exact inputs and outputs of the block are described in the Loxone documentation: https://www.loxone.com/enen/kb/gate/. Please double-check in Loxone Config; this mapping has not been tested on a real Miniserver yet.

Credits and sources

• Firmware and protocol: Gifford47/HCPBridgeMqtt, Tysonpower/HCPBridgeMqtt_tynet
• Datasheets: THVD1406, LMR51610
• RJ12 hole pattern (Molex 95501-2661): taken from the Gerber files of the board by vladimirzrnic in the HCPBridgeMqtt repository (docs/PCB/vladimirzrnic)