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smalljb.jpg (1654 bytes)smakkneo.jpg (1099 bytes)House AV system


Last time I needed to make an addition to my house audio/video systems, I got so confused about what was connected to what and how, I had to draw a diagram......

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VCR3 is mostly used for audio recording of radio programmes, hence the audio distribution system from its output. The time/date generator is a PIC based device which displays the current time and day of week as a video image, recorded alongside the hi-fi audio track, to allow location of parts of a recorded radio programme, and identification of recordings.

VCR1 can be controlled and viewed from any room. This is complicated by the fact that it's fed from the aerial distribution amp, but its UHF output also needs feeding into the amplifier for distribution to all rooms. An external modulator is used, and is switched on in playback mode only by the input switch signal on the SCART connector. Although this VCR has a facility to only enable its internal modulator for playback, setting this option screws up the SCART TV input switching - one of the many annoying bugs and design errors in the shoddy firmware of the Toshiba V-856B VCR.

The infra-red repeater system has emitters positioned close to the equipment they control to avoid 'feedback' to the sensors. The system is a simple homebrew wired one connected via spare pairs in the balanced audio distribution multipair cable. It uses 3-pin IR integrated receiver/demodulator chips, and 555 timer based modulator/transmitters.

The digital audio fibre is 1mm polymer with Toslink type connectors, except for the long workshop run, which uses 100m of glass fibre cable. The receiver module for this link is from a cannibalised ethernet-to-fibre transceiver.

All I need now is a decent universal remote - I've tried several, but none are perfect. The pre-programmed ones have poor support for audio devices and often don't support model-specific features on VCRs. The learning ones are better, but often don't quite have enough memory. Unfortunately learning types seem to be getting thinner on the ground as pre-programmed ones become more popular amongst the techologically-challenged general public.

Of course there's also the issue of neatly labelling the keys, for which I've never seen a decent solution. The best I've found so far is a Philips learning unit, which would be almost ideal if it had a couple more buttons and enough memory for about another 5 functions! Typical - I tried ordering another one of these recently and they've discontinued it now!


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