<
address@hidden> wrote:
> Hello Poine and David,
>
> Thank you! Poine, do you have values for R38, R39, and R40 in the adjustable
> voltage referance circuit to the -VREF terminal of the ADC? Or do I need to
> determine an appropriate value according to the MPX 6115 output at our
> altitude. I'd be happy with a value you're using at the moment and we could
> tweak things once we get ourselves flying.
>
> Regards,
> Jay
>
>
> On Sun, Feb 28, 2010 at 6:18 PM, antoine drouin <
address@hidden> wrote:
>>
>> Hello
>>
>> There is a little scilab script (
>> paparazzi4/trunk/hw/booz/baro_amp.sce ) which you can use to play with
>> the values of the resistors.
>>
>> The values on the schematics, ie
>> R10 = 27e3;
>> R5 = 390;
>> R6 = 12e3;
>> R20 = 560;
>> R21 = 680;
>> gives you an altitude range of -500m:930m ( with ground pressure at
>> 1013 ) which is a bit silly
>>
>> You might want to lower R20, for example
>> R10 = 27e3;
>> R5 = 390;
>> R6 = 12e3;
>> R20 = 220;
>> R21 = 680;
>> gives you an altitude range of -380m to 1530m which is a bit better (
>> you want the negative value if you want to be able to fly at sea level
>> on a high pressure day )
>>
>> There is a slightly better script in
>> paparazzi4/trunk/hw/lisa/pressure.sce which takes sea level pressure
>> into account ( the one in booz doesn't, feel free to improve it )
>>
>> Regards
>>
>> Poine
>>
>>
>>
>> On Sun, Feb 28, 2010 at 9:28 PM, Jayson MacKiddie
>> <
address@hidden> wrote:
>> > Hello all,
>> >
>> > We have decided to add the booz barometer to our Booz main boards. We
>> > have
>> > the parts list but what are the values of R38=Rs, R39=R2, and R40=R1 in
>> > the
>> > adjustable voltage referance circuit to the barometer? Are they to be
>> > specified based on local altitude to take full advantage of ADC
>> > resolution?
>> > Regards,
>> > Jayson MacKiddie
>> >
>> > _______________________________________________
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>> >
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>> >
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>> >
>> >
>>
>>
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>
>
>
> --
> Jayson MacKiddie
>
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