A leak sensor under the sink. A contact on the wine-cellar door. A temperature probe in the plant room. Each can do exactly one useful thing when it trips: send an HTTP request. On its own that’s a notification nobody sees. Paired with the Sonos speakers already in the house, it’s an alarm — audible in every room, repeating until someone deals with it, and with no separate alarm panel to buy or wire.

Two LCD drivers make the fabric: UI Dynamic to catch the webhook and Sonos Chime to make the noise.

Sensor to scene, in one request

Every UI Dynamic control has a webhook URL that fires a Crestron Home event. Hand that URL to whatever the sensor can call — its own webhook field, a Home Assistant automation, a Node-RED flow — and the moment the sensor trips, a Crestron event fires. From there it’s ordinary Crestron programming: bind a scene to the event.

No bridge, no cloud middleman. The sensor speaks HTTP; UI Dynamic turns that into a Crestron trigger.

An alert that won’t be ignored

The scene fires the Sonos Chime driver. Two settings make it a real alert rather than a polite ping:

• Repeat until stopped. A chime set to repeat 0 times repeats until something calls StopChime. An intruder or a flood shouldn’t stop on its own — this one doesn’t.
• A pinned volume. Pin the alert chime to its own high volume and it ignores the house-default ChimeLevel. So a night-mode scene that quietens the music at 11 pm can’t quietly turn the flood alarm down to a whisper. If you pinned it to 95, it stays 95.

Give each sensor its own spoken announcement — “Water detected in the utility room”, “Plant room over temperature” — and the house tells you not just that something’s wrong, but what.

[Screenshot to add: a Sonos Chime set to repeat 0 (until stopped), or the UI Dynamic Webhooks tab]

Arm, disarm and acknowledge — on the tile

Because a repeating chime needs a stop, the acknowledge belongs on a tile the client can reach. A UI Dynamic control does both jobs:

• An arm / disarm control — a two-state button whose state your programming checks before letting the alert scene run.
• An acknowledge control whose press calls StopChime to silence the alert once someone’s on it.

Every call in and out is recorded in UI Dynamic’s activity log, so during commissioning you can trip the sensor, watch the webhook arrive and the chime fire, then acknowledge it — all without a processor console.

Spec it as a safety net, not a security system

This isn’t a graded intruder alarm, and it shouldn’t be sold as one. What it is: a cheap, flexible alert layer over sensors and speakers the client already owns — the leak, the freezer door left open, the plant room, the gate at 2 am — made loud, house-wide and acknowledgeable, using two drivers on the existing processor.

Both are licensed products with a 30-day trial and full licences on their product pages — UI Dynamic and Sonos Chime. The webhook setup is on the UI Dynamic webhooks page, and the chime, repeat and volume settings are on the Sonos Chime pages, both on lcd.network.

Hero image: Photo by Shang Zhou on Unsplash.