Somehow, just about every hobbyist has managed to score a phone or two for his/her junk box. None of them are ex-rental, of course - they have just somehow materialised. But wouldn't it be nice if you could actually do something with them - like make them talk to each other?
Here's a simple circuit which does exactly that. It's based on
our new best friend, the PICAXE-08, which means it is dirt cheap and easy to build. When either phone is picked up, the other one will ring until it is answered or the other phone is hung up.
And the really good news is that your calls don't cost you a
cent.
Whether you build this as a toy for kids (that's what the
circuit was originally designed for), as an intercom between rooms or even buildings of your home, business, factory, whatever; serious or flippant... this will do it.
Its range will depend to some degree on the cabling you use but
could easily be a couple of hundred metres or so. And as we said before, you can even use cordless phones (or one of each) and make a fully wireless intercom.
Incidentally, phones make really great intercoms in noisy areas
because the earpiece is so close to the ear - and you can yell into the mouthpiece to get the message across!
