How to wire a smart relay to a Nice M-BAR gate — yourself, step by step
A gate on the Nice M-BAR board starts listening to your phone without replacing the drive: a smart relay (Remootio or Shelly) goes onto the button input — a dry contact. Here: which two terminals, how to set it up and what not to do.
The relay works in parallel with the button — the board stays as is
The Nice M-BAR board has a button input — a dry contact. A smart relay «presses» it from the app just like the wall button. Photocells, force limiting and remotes stay in place and keep working.
- Gate type
- barrier
- Board
- M-BAR
- Drives
- M3BAR, M5BAR, M7BAR, L9BAR
- Bridge
- (1) (2) ↓
- Labels
- named terminals (BlueBus)
- Supply
- 24 V
DIY: 6 steps and the common mistakes
- Switch off the drive (breaker in the panel). Open the board cover and find the command terminal block.
- Find the button terminals (1)(2) by the labels on the board — not from memory, board revisions differ.
- Connect the two wires of the relay dry output to those two terminals. Polarity does not matter (dry contact).
- Relay power: Remootio — from the board 12–24 V terminals or USB; Shelly — per its model. Never from the command terminals.
- In the app: output mode «pulse / momentary» 0.5–1 s. Connect the status sensor if you have one.
- Power on, test from the button, then from the app. Photocells and force limiting must work as before.
- ❌ Mistake: a relay with a 230 V output (power relay) on the command input — the board burns.
- ❌ Mistake: bridging command to STOP or removing STOP/PHOT jumpers — the gate stops moving or the fuse blows.
- ❌ Mistake: relay output left «on» — the board sees a held button and ignores further commands.
Nice M-BAR terminals — which two
The relay bridges (1)(2) — points (1) and (2) in the drawing. A short pulse = one command (open → stop → close). Nice terminals are named terminals (BlueBus).
Setup: pulse + status
Wire the relay in parallel with the existing button — the same two terminals. Button and remotes keep working.
- Relay output in momentary / pulse mode (0.5–1 s), like a button press. Not «permanently on».
- App command → relay click → the gate moves just like from the button.
- Open / closed status: limit switch or magnetic sensor → relay sensor input → state visible in the app (Remootio ships with a sensor).
- Scenes: geofence opening, schedule, voice, camera-at-gate linkage.
How to power the relay — 24 V AC is not 24 V DC
Always open / always close
Separate OPEN and CLOSE blocks exist: an extra relay across the two contacts of the OPEN block always opens, across the two contacts of the CLOSE block always closes. Several relays can coexist — for example open on arrival plus close on a schedule.
Full control — multi-channel relay
One multi-channel relay gives separate app buttons: Ch1 — close, Ch2 — open, Ch3 — stop. Each channel goes across the two contacts of its own command block.
Remootio or Shelly — which to pick
Remootio 3
Made for gates: two dry outputs, status sensor included, powered from the drive board.
- Keys for family and guests, revocable
- Geofence auto-open, log
- Works without internet, encrypted
- HomeKit / Alexa / Google / Home Assistant
Shelly / 4-channel dry relay
A universal Wi-Fi or Zigbee relay in dry-contact mode. Cheap, lives in Home Assistant and Tuya.
- Separate open / close / stop
- Schedules and scenes
- Sensor and keys are on you
Relay and modules for this board:
Safety and the manual
FAQ
Does Shelly fit the Nice M-BAR board?
A model with a dry (potential-free) contact output does — for example Shelly Plus 1 in detached mode or a 4-channel dry relay. Models switching 230 V must not go on this input.
Why must the relay be in pulse mode?
The input works step-by-step: one short contact = one command. If the contact stays closed, the board sees a held button and ignores further commands.
How do I see in the app whether the gate is closed?
Put a magnetic sensor on the gate (included with Remootio) or use the drive limit switch and connect it to the relay sensor input. The app then shows the real position, not the last command.
Will the remote and the button keep working?
Yes. The relay sits in parallel, nothing is disconnected. All factory inputs keep their function.
What can I do myself and what not?
The low-voltage relay connection is simple. The 230 V side, force-limit check and commissioning are for a certified installer. If in doubt, call one.
Rather not do it yourself? We will
We pick Remootio or a relay for the Nice M-BAR board, wire it to the dry contact, set up status and scenes.