Dive Computer Ramblings

[Robert Helling]

On 10.09.2014, at 14:20, Davide DB <dbdavide at gmail.com> wrote:

Hi everybody,

> The case shouldn't be something very different from this:
> 
> http://www.scubapursuits.com/User/Products/LrgImg/94/apeks-hp-port-button-gauge.jpg
> 
> Maybe that it's too little bbut just add electronics, battery and some USB port.

that’s a mechanical gauge, so not easy to read out electronically. 

A little googling shows that I was a bit too optimistic with the price tag: It seems you can buy pressure sensors that already have the 7/16” UNF thread that could directly go into the high pressure port of a regulator but they cost about $120 alone, see for example

http://www.onlinecomponents.com/honeywell-mlh300bsb10a.html?p=11938376

For hardware noobs like me, basing the readout and storage electronics on something preexisting sounds like a good idea: I found http://www.pololu.com/product/1623 with a $60 price tag that logs onto SD cards and acts like a USB drive when hooked up to a computer and has the additional benefit to be able to charge a LiPo battery when connected to USB.

Combine these two with a small amplifier to match the sensor output to the input of the logger and put everything in a nice sealed case and you are done™.

I cannot really estimate the price of the case but it seems the prototype would be more in the 200-250$ price range and due to the price of the sensor will not fall significantly below that. So it will basically be in the same range as the Suunto pressure transmitter (200 Euro).

Best
Robert

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Robert C. Helling     Elite Master Course Theoretical and Mathematical Physics
                      Scientific Coordinator
                      Ludwig Maximilians Universitaet Muenchen, Dept. Physik
                      Phone: +49 89 2180-4523  Theresienstr. 39, rm. B339
                      http://www.atdotde.de

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