Installations
Add remote unlock and notifications to an existing lock, without replacing it.
Updated August 2026
A Shelly relay turns an existing 12 V or 24 V electronic lock into one you can open from the app, on a schedule, or from a keypad — without replacing the lock itself.
Three common jobs, all the same wiring:
SW input, so any 12 V/24 V third-party reader works.Most 12 V and 24 V electronic locks work with Shelly. Which one is fitted decides what happens in a power cut, and that is the decision that matters.
Powered on to stay locked, releases the moment power is cut. The door opens if power fails. Holding force is typically 150–500 kg.
Common on emergency exits and glass doors.
Powered briefly to release the latch, mechanically engaged otherwise. The door stays locked if power fails. Available in AC and DC variants.
Common on office doors and residential gates.
Motor-driven, with several states, and it can be set up either way. Often reports its own status. Draws considerably more current during a cycle.
Common in high-security and commercial installations.
| Component | Recommended | Notes |
|---|---|---|
| Relay | Shelly 1 Gen4 | 12 V DC, 24–48 V DC or 110–240 V AC, potential-free output |
| Lock | Any 12 V or 24 V electronic lock | Powered separately from the relay |
| Keypad or scanner | Any third-party 12 V/24 V reader | Output wires to the Shelly’s SW input |
| Door sensor, optional | Reed switch and Shelly Plus Add-On | Real open/closed state rather than “a pulse was sent” |
The 1 Gen4’s universal supply is what makes this work across almost any lock system — the same device suits a 12 V strike and a 24 V maglock.
Five steps. Read the safety notice before starting.
The last one is not a formality. If there is no key cylinder, that is the first thing to fix, before any of this.
The relay’s potential-free output controls power to the lock. The reader’s own relay output goes to the SW input — so a valid code triggers the Shelly exactly as a manual switch press would.
Without it the door stays unlocked after every access. With it, the lock releases and re-engages by itself.
Timer settings → enable Auto-Off → 3 seconds
Most readers include a relay output meant to drive a lock directly. Wire that output to the SW input instead of to the lock, and the Shelly does the switching.
Skip this step on an app-only installation.
If the reader will not trigger the Shelly, it is usually because it provides a dry contact rather than a voltage signal. Check the reader’s documentation and set the input type accordingly.
Four tests, and the last one is the one people skip:
Add schedules and notifications afterwards if the customer wants them: a schedule that disables the relay outside opening hours, and an action that notifies on unlock. For real door state rather than “a pulse was sent”, add a reed switch on the Plus Add-On.