'Tilt !! Tilt!! Tilt!!'
I'm looking for a tilt switch (in a PIC project) to detect whether an
appliance has been knocked over and turn it off in that case. I have
been using a cheap, 2 lead mercuray switch, and the BOSS says I need
to get rid of the mercury because it is a liability. Does anybody
know of a manufacturer of a cheap nonmercury tilt switch, such as a
I see one in a Mouser electronics catalog, but they claim they are
the exclusive manufacturer (LIES!!) and it only has one lead ("What
is the sound of a one-lead switch closing, grasshopper?") making it
hard to solder onto a circuit board.
-- Lawrence Lile
"Nyquist was an optimist."
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|I know I've seen those somewhere else...
You could use a magnetic reed switch & have a magnet flip over away
from the switch when the box is knocked over, so it's close enough to
close the switch normally but too far away when tilted, but that's not
necessarily what you want.
I could swear that http://www.mpja.com used to have these ball
switches in quantity, too. Their search link's broken as is their
frame-based e-mail link (I e-mailed them on that!) Scan the surplus
places? The only problem with those ball switches is that if dirty they
quit working, so consider a covering lid of some kind? Cat fur would be
a bad bad thing to work it's way in there, nu? <G>
And finally, a devious one; Put a small weight (in a short tube,
say), atop a PCB-mounted NO switch; If tilted, the switches' spring
should be enough to open the circuit. Feel free to do this with the
weight riding a slot in the PCB backplane of the device, if that's
vertical, it should work surprisingly well I think. And it's cheap &
pretty small. Just have the PIC "watch that switch on occasion" <G>
Same thing can be made umpteen ways (a ball bearing in a little cup,
with 2 third-ring contacts at the bottom, you just need "too tilted"
here not acceleration in % of a "G"!)
Could also use a spring-loaded toggle switch, with a weight on the
toggle (The thought comes to mind that you could push down on a lever to
"arm" the on switch, and pulling up or tilting could turn the device
off, using hystereisis of the safety mechanism; Might be better to
separate the on/off functions from tilt/safety, though!)
Lawrence Lile wrote:
Lawrence Lile wrote:
> I'm looking for a tilt switch (in a PIC project) to detect whether an
> appliance has been knocked over and turn it off in that case.
The "standard" is a hermetically sealed "ball-in-a-can" in a multi-
lead (one in the centre even) TO-3-style case. Oatley had some:
They are probably not in the webpage listings at all, but you could
email Branko world.net and ask him what he has/ what he oatley
Bike alarms use swinging reeds with a strong magnet and coil as sensor
or a large weight hung on a piezo assembly (this has been discussed
before; you need limit stops fitted!). These sense movement, not tilt.
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