Home grown wireless intercom

[Ryaowe]

I've been wanting to try this project for a while, but it's a bit over my head. I'm hoping for some help to point me in the right direction.

I'd like to build a very small form-factor, multi-station wireless intercom for my home. It'd be really nice if I could make it small enough to fit in a one gang electrical box, but still leave room for a small light switch (also need to find a good mini light switch that can handle 15 amp). The idea being that it would replace a standard light switch, and take power from the existing wiring in the wall. Something kinda like the bRight switch, but much simpler in scope.

I have a limited understanding of electronics, and have done some simple projects with arduino, but never anything with audio. The more I try to learn about audio, the more complicated it seems.

My first thought was to use a Spark Core, and do everything over wi-fi, but that kinda seems heavy-handed for an intercom system. I've seen a few projects that hook a mic up to the analog input of an arduino and read it at an 8khz sample rate, and similar projects that hook a speaker up to the analog out and write out to it. Would something that simple be effective? Or would the audio quality be horrible? I'm also not sure if the Spark Core would be fast enough to sample the analog input and stream it in real time.

Maybe it would be better to have the intercom work over FM radio or something along those lines? In that case, I'd still like to have one station that I could control from a network-enabled microcontroler or a raspberry pi so I could make a smart phone app that broadcasts to the intercom stations.

So... is this way too much for a beginner like me to undertake? Any recommendations on the best approach, or good resources for learning about audio input and output?

 

[JimW]

Google "power line communication module". There are several small pre packaged modules that can send and receive data over the AC power lines. Link that with a small micro and you should be good to go. The micro can do a simple data sampling with an A/D, embed that into a data packet with a simple protocol for broadcasting to the other devices. Conceptually it doesn't sound too hard to do in the size that you are interested in.

A possible candidate would be:
http://www.gobizkorea.com/catalog/p...3&pageNo=1&pageVol6&listStyle=L&objId=1008265
Watch the data rates though, some are pretty slow. And others are for DC power only.

JimW

 

[KTW]

Could sharing a transformer with a neighbour cause privacy issues if they have a similar device?

 

[Gryd3]

Could sharing a transformer with a neighbour cause privacy issues if they have a similar device?

That's a big 'if'. Besides, some of these devices don't have very good range.
Sometimes you are lucky if it can get from the house to the garage.