How to connect two Shelly 1 Gen3 to a swing gate (full and pedestrian opening)

A slightly stressed customer writes in: he bought the Gen3 kit for his swing gate (a GEA Deko motor) and, reading up, realised that because the Shelly 1 Gen3 is single-channel, he needed a second, loose one to handle both the full and the pedestrian opening. He already has both parts —the complete kit and one more Shelly 1 Gen3— but doesn't know how to wire it. Let's take it step by step and calmly: you thought it through right, and the install is simpler than it looks.

Why you need two Shelly 1 Gen3

The Shelly 1 Gen3 has a single contact (one channel), so it can only give one command. A swing motor with two modes —open fully or open one leaf to walk through— has two separate inputs on its control panel. That's why you need two Shelly, one per input:

• The kit's Shelly (the Automatic Gate Pack, which comes with the Shelly 1 Gen3 + the Plus Add-on + the magnetic sensor): you use it for the full opening and, thanks to its sensor, to know whether the gate is open or closed.
• The loose Shelly 1 Gen3: you use it for the pedestrian opening (a single leaf).

Both are controlled from the same Shelly app, as two independent buttons: «open full» and «pedestrian». So your purchase was the right one.

How each Shelly connects to the panel

The key is that the Shelly 1 Gen3 has a dry contact (potential-free): its output terminals O and I carry no voltage of their own, they're like the two wires of a push button. The install is this:

1. Each Shelly's dry contact (O–I) connects, with two voltage-free wires, to the panel's button input, in parallel with the button that's already there. That way the remote and the wall button keep working the same; the Shelly just adds another way to give the command.
2. The Shelly no.1 (from the kit) goes to the full-open input.
3. The Shelly no.2 (loose) goes to the pedestrian input.
4. The Shelly's power (its L/N terminals) is a separate circuit from the dry contact. Power it according to what your panel provides and the device's accepted range.

What you must never do: don't cut or run the motor's power through the Shelly. The dry contact only «presses» the command input; the motor's panel still governs the power.

Identify your two inputs correctly: on the GEA Deko panel, find the full-open input (often labelled «step-by-step» or similar) and the pedestrian one. Confirm them in your motor's manual before wiring, because the exact terminal names change from one maker to another.

Set them to pulse mode (very important)

A motor expects a momentary pulse, exactly like a press of the wall button. If you leave the relay closed (bistable mode), it's like holding the button down the whole time: the motor gets confused and can be damaged.

So, in the Shelly app, on each of the two devices, turn on auto-off (Auto-Off) and set 1 second. That way, each time you trigger it, the Shelly closes the contact and opens on its own after a second: a short pulse. Do it the same on no.1 (full) and no.2 (pedestrian).

Tip: give them clear names in the app («Gate — full» and «Gate — pedestrian») so you don't mix them up later.

The gate's status and safety

Knowing whether it's open or closed. The magnetic sensor that comes with the kit (limit switch) connects to the Plus Add-on fitted to Shelly no.1. In the app you'll see the gate's real status and can create alerts (for example, «gate open more than 10 minutes») or scenes (a light coming on when it opens at night).

Safety, before leaving it on automatic. A motorised gate needs its protections: photocells across the path and force limitation that reverses the movement on hitting an obstacle. Don't enable automatic closing without photocells.

A professional installs this. Working on a gate's control panel isn't a household socket: there's voltage and a heavy gate in motion. If you're not sure about the install, have an installer connect it. We'll advise you on the exact diagram for your equipment.

Frequently asked questions

Why can't a single Shelly handle both openings?

Because the Shelly 1 Gen3 has a single contact. The full and the pedestrian opening are two separate panel inputs, and each needs its own contact to «press» it. That's why two Shelly, one per input.

What are the Shelly's O and I terminals?

They're the dry-contact output (potential-free): two terminals that close onto each other when the relay acts, supplying no voltage. They wire up like a push button, in parallel with the button the panel already has.

Will my usual remote keep working?

Yes. Because it sits in parallel with the existing button, the remote and the wall button keep working the same. The Shelly only adds control from your phone.

Why is pulse mode so important?

Because the motor expects a short press. If the contact stays closed, it's like holding the button down and the motor may misbehave or be damaged. With Auto-Off at 1 second you give that short pulse.

Where do I connect the gate sensor?

The kit's magnetic sensor goes to the Plus Add-on fitted to Shelly no.1. That Add-on is what reads the limit switch and brings the status (open/closed) to the app.

Can I install it myself?

If you have experience with control panels and you respect the protections, yes. If not, it's a job for an installer: there's voltage and a gate in motion. We'll help you with the diagram for your motor.

Summary

• Two Shelly 1 Gen3, one per input: the one from the kit to the full opening, the loose one to the pedestrian.
• Dry contact (O–I) of each Shelly in parallel with the panel button, with two voltage-free wires.
• Pulse mode on both: Auto-Off at 1 second, so they «press» like the wall button.
• The kit's sensor goes to Shelly no.1's Plus Add-on and gives you the open/closed status.
• Safety: photocells and force limitation; and, when in doubt, an installer.

Send us the exact make and model of your GEA Deko panel (or a photo of the terminal strip)? With that we'll tell you which terminals each Shelly goes to, with no margin for error. Technical support in Spanish and English, and shipping from Spain.