Re: Strain gauge

[Robert L Bass <sales@xxxxxxxxxxxxxxxxxxxxx>]

> Has anyone here ever mounted strain gauges on
> basement jacking posts to measure the load changes
> of the floor supported by the posts?

I imagine someone has though I haven't.  Coincidentally, there
are strain sensors that measure floor joist flexing to detect
burglars.  A company called Sure Action makes them.  They call
the products "Pulsors".  They give off a tiny electrical current
when the joist flexes due to an intruder's weight above.

You could measure the current and build a simple circuit to
detect occupancy  but it only responds to flexing -- not a static
load -- so it still doesn't solve the perennial problem of room
occupancy for HA.  :(

I've used these sensors on my own jobs a few times.  When
properly installed they work well.  Poorly installed they won't
detect anything smaller than Mama Kass.

The company also makes processors to trip an alarm or HA system
sensing zone when it detects movement above.  The main benefits
of these things are they're completely undetectable from the
protected area and they are immune to most of the things that
cause false alarms with motion or glass break detectors.  The
disadvantage is they require more effort to install than the lick
'n'stick wireless motion detectors that have become standard fare
in the alarm industry.

If you want to experiment with one of these sensors let me know.
Although I don't currently list them online, I carry Sure
Action's other lines and can provide these as well.

--

Regards,
Robert L Bass

Bass Burglar Alarms
The Online DIY Store
http://www.BassBurglarAlarms.com

--

Never underestimate the power of very stupid people in large
groups.