I don't remember which chip TonyK used originally, but there are MEMS
based membrane pressure sensors out there with 0.5 psi full scale (or
even smaller scales). I plan to do this with a Atmel controller, and
when I get around to it, I will post it here for everyone's benefit.
Here is one:
http://www.mouser.com/ProductDetail/Silicon-Microstructures-Inc/SM5852-003-G-3-NR/?qs=sGAEpiMZZMvhQj7WZhFIAE1JN4kSCAy2w%2fQb30WxsAg%3d
On Wed, Nov 27, 2013 at 3:17 PM, Jan de Jong <jan_de_jong@casema.nl> wrote:
>
>
> What has always puzzled me.
> According to the specifications of the sensor the uncertainty in the initial
> zero offset is +/- about 25 % of our full scale of 0.5 psi (35 cm of water).
> Which in the general case would require a generous bias (using an opamp) to
> the output of the instrumentation amplifier. Ofcourse, maybe Honeywell is
> way too pessimistic in its specification. Tony K must have decided so?
>
> Jan de Jong
>
>
> On 11/27/2013 7:30 PM, Paul McAllister wrote:
>>
>> Hello everyone,
>>
>> I have been using this in my aircraft since 2004. Tony K did the original
>> design work and it is based on a PIC micro processor. It is calibrated in
>> 1/10th increments from empty to full and displays on a 10 segment LED or an
>> analogue display.
>>
>> There isn't any PCB design and most people who have built them seemed to
>> have trouble in getting them up an running. It's not complex to build but
>> they do require a bit of tinkering to get them working, installed and
>> calibrated. In my case I set up a water manometer on my bench to get it
>> debugged and working.
>>
>> The only issue I have had is that despite having a static vent on the
>> differential side, the gauge does read high when climbing and low when
>> descending and it takes a few minutes to stabilize in these scenarios. It
>> hasn't been enough of a problem for me to bother with trying to fix it.
>> Other than this it has functioned reliably for the last 9 years.
>>
>> I use this in conjunction with my fuel totalizer and I do not have a sight
>> gauge.
>>
>> I do have the source code so I could burn some PIC's for people, but
>> before doing this I will need Tony K's permission. I guess if there was
>> enough interest I could create a PCB design and build a batch of them. I
>> will need to think on this some more before I sign up for this. :)
>>
>> Regards, Paul
>>
>
>
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