budgetDiscontinuedlocal: excellentFully controllable on your LAN with no internet dependency.Wi-Fi
Price
$45verified Nov 3, 2026
HA fit
●●●●●excellent
Offline
yes
Setup
advanced
Hub needed
no
Discontinued. The manufacturer no longer sells this one new, so a retailer link here can land on remaining stock, a used or refurbished unit, or a successor model - check what the listing is before buying.
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Quick verdict
Shelly has discontinued the Plus 1 relay this build is based on, and its US store sells the Shelly 1 Gen4 as the current version; the same wiring works on that relay. A Shelly relay wired to any 12V piezo/strobe turns a cheap industrial siren into a fully local, hub-free Home Assistant siren. The Shelly relay is controlled directly over the LAN by Home Assistant with no cloud dependency. Just note: DIY wiring required; not a turnkey siren.
Notes last checked Jun 2, 2026.
Compatibility snapshot
Home AssistantexcellentFull local control, no cloud needed. Native Home Assistant integration or a local protocol.
Apple HomenoneNo official support on this platform.
Google HomenoneNo official support on this platform.
AlexanoneNo official support on this platform.
Works offlineyes
Setupadvanced
Extra hub neededno
Powermains/12V
Local control facts
Home Assistant: shelly integration, Local Push, Platinum on the quality scale (home-assistant.io, checked Oct 10, 2026)
Why it stands out
100% local control with Shelly's HA integration and auto-discovery
Use any loud 12V wired siren/strobe, indoor or outdoor
No additional hub; runs even if internet is down
Reasons to hesitate
DIY wiring required; not a turnkey siren
On/off only (no tones/volume) unless the siren supports it
You must source the physical siren/strobe separately
Best for
Tinkerers wanting a loud, cheap, fully local wired siren
Avoid if
you want a finished, plug-and-play product rather than a DIY/wiring project
Privacy and local-control notes
The Shelly relay is controlled directly over the LAN by Home Assistant with no cloud dependency.
Home Assistant support: supported · integration path: Shelly (local).
Buying reality check
Price notes: The Shelly Plus 1 relay itself is about $42 on Amazon (verified 2026-09-06). The 12V siren or strobe is a separate purchase, so price the pair together rather than the relay alone.
Verified price reads: lowest seen $42, latest $45 on Nov 3, 2026.
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