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heyydude · 14th February 2008, 12:08

When we were doing some of the early testing for the US Navy Mark 16 Mod 2, we built a Secondary housing which used the same Piezo Switch that is in the Hammerhead - we found that it's sensitivity increased at 28 degrees F (where the units are tested in brine). We did not find any where the sensitivity decreased, but I would imagine this could be possible.

As one of the biggest consumers of these parts, we work very closely with the manufacturer to adjust their assembly technique to best fit our needs, and I'll bring this issue up with them next week.

As someone pointed out, these are sealed/filled switches, and the piezo element in them is made out of quartz crystals, so what we are probably seeing is the metal housing changing shape based upon the temperature, and that is somehow affecting the sensitivity.

But like many things in manufacturing, every change comes with a trade-off. We could get these made out of plastic, but then someone would crack or puncture them on the side of the boat, etc.

BTW: We couldn't use these switches in the Navy sets for reasons important to the Navy - the ones used in the Mark 16 are (of course) custom made.

Kevin Juergensen
Juergensen Marine, Inc.

14th February 2008, 12:08	#12 (permalink)
heyydude King of the Geeks Current Rebreather/s: MK 15.X Optima Other CCR Other Rebreather/s: Other CCR Join Date: May 2005 Location: Addison, Pennsylvania Posts: 337	Re: HH buttons get stuck when it's 29 deg F When we were doing some of the early testing for the US Navy Mark 16 Mod 2, we built a Secondary housing which used the same Piezo Switch that is in the Hammerhead - we found that it's sensitivity increased at 28 degrees F (where the units are tested in brine). We did not find any where the sensitivity decreased, but I would imagine this could be possible. As one of the biggest consumers of these parts, we work very closely with the manufacturer to adjust their assembly technique to best fit our needs, and I'll bring this issue up with them next week. As someone pointed out, these are sealed/filled switches, and the piezo element in them is made out of quartz crystals, so what we are probably seeing is the metal housing changing shape based upon the temperature, and that is somehow affecting the sensitivity. But like many things in manufacturing, every change comes with a trade-off. We could get these made out of plastic, but then someone would crack or puncture them on the side of the boat, etc. BTW: We couldn't use these switches in the Navy sets for reasons important to the Navy - the ones used in the Mark 16 are (of course) custom made. Kevin Juergensen Juergensen Marine, Inc.
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