shock detection

On further consideration, if I spent $25-40K on something "handheld", I'd expect the maker to have bothered to engineer it to take the normal things that can be expected to happen to a hand-held item, such as being dropped 3-8 ft onto a concrete or steel surface (in any orientation), without blinking, much less breaking. If it can't even be "bumped", you'd better sell it as a suitcase-sized item, with the package you have now sitting in the middle of a lot of soft foam, surrounded by a hard shell.

made

No, the gold does not. However, the owner of the toe beneath it does.

Tales of Fort Knox eh...

On topic: there are clear bouncy ball things with an LED flasher inside. A spring, clearly visible, bounces against a pin. A couple second one-shot is activated that runs the flasher.

(Hmm, I wonder how they get the battery inside there. Rubber isn't cooked at a very cold temperature. Must be a different elastomer.)

Any solenoidal spring always flexes easier in bending than in compression, and any axial force will soon end up converted to torsion and bending due to the spring's coiled geometry. Only one spring is necessary, but good luck calibrating it. It'll also have a resonant peaked response unless you immerse it in glycerin.

Tim

-- Deep Fryer: A very philosophical monk. Website @

How accurate does the timestamp need to be? Unless it needs to be accurate to the nearest second, you can just power up the system periodically to check whether the glass tube is still intact.

This approach is commonly used for carbon monoxide detectors, which typically take one measurement every 30 seconds and run for 5 years on the supplied battery (which cannot be replaced, to ensure that the unit is replaced as a whole; the sensor has a limited lifespan).

but, i don't think that works unless it's powered up. The poster wants it to work even with the batteries out. That would imply a mechanical release snap switch which works with sudden stops how ever, the one's i've seen are not small because they need a little inertia to make it work.

meddelelsenews: snipped-for-privacy@57g2000hsv.googlegroups.com...

what you need is a small "inertia switch" mounted on a small mini board or maybe part of your main board to be operating by a back up batter which maintains a low power pic or like that with a TOD clock in it that supports a calendar.

inertia switches are very popular and are getting small. You could most likely construct a complete potted unit with a proprietary plug in device that only you would have the resources to connect to. I've seen this in medical devices so that only the manufacturer that made the equipment could connect up to it and down load information about service times and may other things that we don't want to know about. These devices normally have their own batteries in the potting of the device.

If we put him in a box, do you think he could tell if he was stationary, or falling?

John

Ahah! This is interesting idea: use disposable detector and check it every once in a while. Thank you, I'll look into it...

Nah, put him in the box with a radiation-activated cyanide source. Then open the box and view his wavefunction.

Tim

-- Deep Fryer: A very philosophical monk. Website @

The vomit comet is a good example. We know they are in free fall but to them they are in 0g. (Of course they know its free fall only by deduction)

If you jumped out of a plane with your eyes closed and there was no atmosphere then you would not know your falling but you would think you are floating(exactly like the vomit comet... the plane itself acting to isolate you from the atmosphere) until you hit the ground.

I don't mean that you cannot detect acceleration but simply that you cannot tell the difference between different "kinds". Although I suppose for practical considerations it doesn't matter much. A 24k solid gold handheld probably will never end up in the vomit comit. Also I seriously doubt that he's really interested in detecting "free fall" but impact(my guess is to void the warranty).

Although, for example, if someone took the handheld on a plane its possible that it might detect "free fall" if it was not designed properly(or maybe that would need to be a dragster?).

I think you'd perceive it the other way - in weightlessness or jumping out of an aircraft without an atmosphere you'd think you were falling, at least until you were conditioned to the effect.

We're well-programmed to expect 1 gee downwards all the time.

I don't know.? For the "abuse" part of this, you can probably arrange "lie-detection" services with a local company. If you suspect purposeful employee abuse, that alone might solve the problem (i.e., fear of losing one's job.)

And would probably be cheaper and better in the long run. (Besides, you could ask other questions - like who's sleeping with whom, who's on drugs, who's stealing from the Company, stuff like that.)

-mpm

Except on Monday mornings, when it's 1.8.

John

($25k-

You need Shockwatch