[Sugar-devel] Interesting USB-pluggable robots, controller boards, and sensors

[James Cameron]

G'day Tony,

The LM567 is a voltage controlled oscillator with phase detectors ...
and isn't often used these days, so it might be a challenge to find a
realistic price.  Then you need one per detected frequency.

An alternative might be to use a DTMF decoder chip, such as the 8870,
since this provides more channels.

I've controlled amateur radio repeaters using an XO as the DTMF source,
even through the speakers.

-- 
James Cameron
http://quozl.linux.org.au/