Baby Listener over mains (eg HomePlug)

[Steve Walker]

Hi - Some ideas or links please -

Wanting to hack up a sort of intercom system, so that people in location A can overhear discussions taking place in location B (and rush to help if they hear shouting and furniture breaking). Let's say the venue is a kebab shop where the odd drunk wanders in and causes trouble, and the rest of the family are generally upstairs at the back.

I thought for some reason that there were now volume-sensitive baby listener devices which transmit over the 240v circuit (like HomePlug ethernet does). A quick google, and I can't see any like that - many are still radio-based, with DECT appearing occasionally. Not sure if radio will carry through the numerous floors & walls, and would prefer that the audio wasn't broadcast on an open channel anyway.

Really need to avoid running cable if possible, although this would be simpler. Need to use this protection flexibly in several different rooms and under diverse circumstances (yes, it's not really a kebab shop).

I throw myself on the collective mercy & wisdom of the hive mind... TIA!

[The Medway Handyman]

Sounds more like a knocking shop to me :-)

[Lobster]

Must have been a VERY quick Google...

?ModuleNo=23041&doy=23m2&C=SO&U=strat15

[Owain]

The volume from the shop would have to be loud enough to be heard over the family telly etc, and they would hear all the ordinary kebab shop noise as well.

This is (if it really is a kebab shop...) a workplace, so health and safety legislation would apply (protection of workers from the public). I would suggest that CCTV with recording, good enough for facial recognition, together with appropriate panic buttons, would be better. The police operate a 'radio link' scheme for shops and pubs in some areas, and would be a good source of advice.

What you need is a wireless intercom. Maplin do one.

sure why it's three channel if it can only be used in pairs.

Note these (from personal experience) do not always work well on ring circuits (they can be better if wired into lighting or other radial circuits) and it is quite likely that the kebab shop will be on a different mains phase (may even be 3-phase) from the flat above. They can however be listened in to sometimes from adjacent houses on the same phase.

Alternatives might be stage type radio-microphones (usually limited battery life on the microphone though; albeit less likely to be overheard), or bugging-type radio transmitters (on broadcast FM likely to be overheard/detected, less likely on airband which some use), or even wireless CCTV cameras (limited battery life again, but most come with mains adapters).

If you just need an alarm when an unexpectedly loud noise occurs, an infrasonic detector alarm might suit

chance of any further clue as to the real requirement? ;-)

Owain

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Lobster saying something like:

[John Rumm]

So you can have more than one set operating concurrently... (IIRC, the two channel ones they used to sell would work in numbers greater than two anyway - so I don't know if their comment is actually true for these).