289 chatbox

Description

Is your journey too noisy? Can you converse with your passenger at more than 5mph? If the answers are yes and no, then you need an intercom unit, as used by some bikers and car rally drivers to chat with their navigator. You need a pair of headphones with a boom microphone attached and designed to cut out as much external noise as possible. Then you need an intercom amplifier which works from a small battery which is separate from the car's supply. This amplifier feeds each microphone signal through a volume control to the other pair of headphones.

So far, so good. But what if you cannot do without the music you used to enjoy before you got the kit car bug? Or if you are a real pro driver and need a satellite navigation system to fnd your way to your favourite pub? Put the headphones on and you won't hear anything other than your passenger's conversation......

At this stage, you will need the 289 chatbox which has been designed with just this situation in mind. You get an amplifier unit with an extra input for connection either to the car stereo system or satellite navigation system (these use a speaker to talk to you). The only disadvantage is that your stereo will be mono, since the headphones come that way. The enterprising constructor might be able to take them apart and re-wire them for stereo, but you would then need a stereo version of the 289 chatbox. This is possible, but would double the component count and thus almost double the cost.

The cost of this amplifier unit is a mere £60 inc VAT. For readers who like to make everything themselves, there will be a kit version containing all the parts you need - a snip at £40 inc VAT. These prices do not include the headphones!