A simpler approach would be to directly connect one of these
differential sensors to a programmable panel meter, like this one:
http://www.jameco.com/Jameco/workshop/ProductNews/panelmeters.html
Then you wouldn't have to build any circuits or boards.
On Wed, Nov 27, 2013 at 7:51 PM, Jan de Jong <jan_de_jong@casema.nl> wrote:
>
> Tony K used the original large version of 26PC01??? , now available as
> 26PC01SMT at both Mouser and Digikey.
> Two important properties:
> - temperature compensation for the range 0 to 50 degrees C
> - fuel compatible (fluorosilicone seal I believe)
>
> On 11/28/2013 1:18 AM, Andrew Sarangan wrote:
>>
>>
>>
>> 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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