Blackout Announcement System
PoE-backed emergency announcements and lighting that survive the outage they exist to announce.
- Text-to-speech announcement over the house audio when mains drops
- Battery backup fed through PoE so the node stays up with the network
- Audio path switches to a battery-powered speaker on loss of mains
- Emergency lighting on the same backup domain
A system whose entire job happens during a power cut has an obvious bootstrapping problem: it has to outlive the event it is reporting. The approach here is to hang everything off the PoE domain, which is already battery-backed for the network, rather than building a separate UPS.
On loss of mains the node announces the outage by text-to-speech, switches the audio path from the normal house speakers to a battery-powered one, and brings up emergency lighting.
Why it is on hold
The design is sound but the power budget was never properly measured. “Battery backup” is only meaningful with a number attached — how long, driving what load — and until the announcement speaker and lighting are characterised under real discharge, the runtime claim is a guess. Parked until that measurement is done.