New Inventors ABC TV - how does the thickness gauge work?

On the program, they actually said that the rare earth magnet is the ball bearing, and did not say what sort of magnet the tip was.

In any event, I guess that somehow they are measuring the force on the magnet in the tip.

Andy Wood snipped-for-privacy@trap.ozemail.com.au

**Buggered if I know. The link is useless. I watched it last night and thought an explanation would be forthcoming. Presumably, it uses some kind of magnetometer. Perhaps a strain gauge?

Yeah, a strain gauge I reckon.

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Trevor Wilson
www.rageaudio.com.au

Yeah, the link is useless - especially as it is titled "how it works".

Ok if the ball is a magnet then maybe a strain gauge as you/trevor are suggesting. I was thinking of a hall sensor or similar but the field will change as the magnetic ball rolls.

I didn't see the show, but it sounds like a re-invention of this:

Inventors huh? This thing has been around for yonks, and adding a digital readout isn't an invention, just simple application of existing technology.

If they had any sense, they'd build one to measure body filler in cars under the paint. A lot more money in that than in lutherie.

Clifford Heath.

Yep, very similar - just a different means of displaying the thickness. Hall effect sensor?

One of the other "inventions" that won the episode was a pressure mat intended for security applications based on an optical fiber - standing on the mat attenuates the light passed through the fibre. An old idea as well but it still won the show.

The up side of the episode was that neither that annoying Indian Professor woman or that James Moody tryhard were on the panel. I can't complain too much as I still watch it.....

Interesting. So it is not a completely new idea, but I think it is a bit more than just digital vs analog readouts.

If I understand how the Hacklinger works, you have to watch the gauge carefully as you slowly increase the lifting force, and make a note of the reading when the upper magnet detaches from the bottom of the tube it is in (it can't move very far, so the lower magnet does not drop off).

Being able to get a continuous reading is a big improvement. Andy Wood snipped-for-privacy@trap.ozemail.com.au

they already have built one that measures bog in car bodies , at my brothers work a inspector that comes around to check cars has one.'

thickness to >

the base (against the wood being measured) and a

And a far better method - the radiation thickness gauge - has been around for at least 50 years. You use a suitable source of radiation that passes through the material to a detector. Simple and it works through all materials - try using a magnetic sensor with ferromagnetics. Why is measuring scraps of wood worthy of a prize in the year 2011 anyway ? Seems the ABC is lost in the past.

MMmmm I think nature already invented one of those - its called a magnet

David