Today's Message Index:
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1. 03:58 PM - Pressure transducer for airspeed (Paul McAllister)
2. 05:12 PM - Re: Pressure transducer for airspeed (Richard E. Tasker)
3. 05:34 PM - Re: Pressure transducer for airspeed (Ken)
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| Subject: | Pressure transducer for airspeed |
Hi All,=0A=0ACould some offer a recommendation for a suitable pressure tran
sducer to measure airspeed.- The intended use is to read is with an ADC /
Pic Micro along with a few other parameters so I can automate my cowl open
ing / closing, and perhaps a few other functions such as gear up warning.
=0A=0AThanks,- Paul=0A
Message 2
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| Subject: | Re: Pressure transducer for airspeed |
Silicon Microstructures Inc. makes a nice sensor that can be used for this. The
SM5882 is available in 0.6 and 1.5 psi full scale versions (depending on what
the maximum speed you want to measure).
These are fully conditioned sensors with both analog and digital output. You would
use the differential version which you can use directly with the pitot and
static inputs to get IAS.
Well, not IAS from the pressure sensor. You get the difference between pitot and
static pressures that can be converted into IAS with the following equations:
Airspeed = ((5.0 * (((((PitotPressure - StaticPressure) / 1013.25) + 1) ^ (2.0
/ 7.0)) - 1.0)) ^ 0.5) * 661.48 (where the pressure units are millibar)
or
Airspeed = ((5.0 * (((((PitotPressure - StaticPressure) / 14.69) + 1) ^ (2.0 /
7.0)) - 1.0)) ^ 0.5) * 661.48 (where the pressure units are psi)
If you want to save a bit of money and do all the A/D yourself they also make the
SM5652, although the calibration accuracy is not quite as good as the above
sensors.
To get TAS you would have to have some way of measuring outside pressure (static
pressure) separately. They do make a version (SM5822) that will do that.
Dick Tasker
Paul McAllister wrote:
> Hi All,
>
> Could some offer a recommendation for a suitable pressure transducer to measure
airspeed. The intended use is to read is with an ADC / Pic Micro along with
a few other parameters so I can automate
> my cowl opening / closing, and perhaps a few other functions such as gear up
warning.
>
> Thanks, Paul
> *
>
>
> *
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Message 3
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| Subject: | Re: Pressure transducer for airspeed |
Might also be worth looking at the line of sensors similar to the
MPX5050DP-ND that I used for an instrument vacuum sensor. They have ones
suitable for airspeed if a 0 to 5 volt output is adequate or the
microprocessor already has an ADC in it.
Sparkfun.com is also a good resource for such projects.
Ken
On 8/7/2011 8:08 PM, Richard E. Tasker wrote:
> <retasker@optonline.net>
>
> Silicon Microstructures Inc. makes a nice sensor that can be used for
> this. The SM5882 is available in 0.6 and 1.5 psi full scale versions
> (depending on what the maximum speed you want to measure). These are
> fully conditioned sensors with both analog and digital output. You would
> use the differential version which you can use directly with the pitot
> and static inputs to get IAS.
>
> Well, not IAS from the pressure sensor. You get the difference between
> pitot and static pressures that can be converted into IAS with the
> following equations:
> Airspeed = ((5.0 * (((((PitotPressure - StaticPressure) / 1013.25) + 1)
> ^ (2.0 / 7.0)) - 1.0)) ^ 0.5) * 661.48 (where the pressure units are
> millibar)
> or
> Airspeed = ((5.0 * (((((PitotPressure - StaticPressure) / 14.69) + 1) ^
> (2.0 / 7.0)) - 1.0)) ^ 0.5) * 661.48 (where the pressure units are psi)
>
> If you want to save a bit of money and do all the A/D yourself they also
> make the SM5652, although the calibration accuracy is not quite as good
> as the above sensors.
>
> To get TAS you would have to have some way of measuring outside pressure
> (static pressure) separately. They do make a version (SM5822) that will
> do that.
>
> Dick Tasker
>
> Paul McAllister wrote:
>> Hi All,
>>
>> Could some offer a recommendation for a suitable pressure transducer
>> to measure airspeed. The intended use is to read is with an ADC / Pic
>> Micro along with a few other parameters so I can automate my cowl
>> opening / closing, and perhaps a few other functions such as gear up
>> warning.
>>
>> Thanks, Paul
>> *
>>
>>
>> *
>
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