On 24 Sep 97 at 8:20, Peter Baines wrote:

> Firstly "Thanks to all who responded to this thread so far" Your
> Ideas have been an insperation. In fact I have now concluded that I
> probab;y don't actualy require an Accelerometer but a 3 DOF movment
> detector, I am trying to build a small device that I can attach to
> my snowboard that will sound a LOUD alarm if anybody tries to
> "Borrow" it without my permission. It will have a small keypad to
> arm/dis-arm it and must be about the size if a ciggarett packet. it
> will run of a 9V battery. I have most of the keypad and I/P O/P code
> sorted so far it's based on a 16c84. So if anybody has any ideas on
> motion dectection please let me know. It dosent have to be linear
> just digital will do. IE motion /no motion but the sensivtivity must
> be quite good.

There's something like that built into my alarm clock - its a 2 part
one - slides apart - one side is conventional quartz clock and
'normal' pip pip type alarm - other side is an 'industrial strength'
- "747 at 10 metres" variety.  Anyway, when you split it, the
industrial strength alarm has a slide switch on it, and a short
length of cord.  Idea is - you hang it on a motel door, to warn of
onexpected entry.  I suspect the device is using the very loud piezo
as both a mike and a sonalert - cuts down on parts.  Its
ultra-sensitive, there's absolutely no way you can remove it from
door without triggering it.  (it has a long attack envelope for the
volume - otherwise it'd be impossible  to disarm.)
MikeS
<mikesmith_ozNOSP*M.relaymail.net>
(remove the you know what before replying)