We've made some very cheap and simple intercoms. You need (per set of two)
- Two plastic beakers - think camping style tough plastic. We bought ours from a local cheap shop. Four for £1
- Wire - we used 100m brown 2 core equipment cable from Rapid - catalogue number 01-0242
- Two 60 mm 8 ohm miniature speakers, again from Rapid -cat.no. 35-0130
- Soldering iron
- Wire strippers
- Glue gun
....Lots of patience!
First I drilled a suitable sized hole in each beaker. I had to put masking tape on to stop the drill slipping. We tried several at a time, but the bottom ones cracked, so it is a one at a time job.
Then choose your length of wire. We went for about five metres - plenty long enough to get a couple of doors between ends.
Strip the wire, feed the cups on and then solder the speakers onto the wire. Pull the speaker out and then tie a knot to stop strain on the wire. Repeat for other end. Push the speaker as far into the beaker as it will go, and then run a ring of glue from the gun around to hold it in place. I also put a blob in the hole the wire pokes through in the bottom of the cup as an extra safety point.
Then voila! You have some pretty nifty intercoms which will work round corners, and with a slack wire.
--Beaky 09:56, 30 January 2009 (UTC)