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Pressure transducer for airspeed

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l_luv2_fly(at)yahoo.com
Guest

Posted: Sun Aug 07, 2011 2:58 pm Post subject: Pressure transducer for airspeed

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



 [quote][b]

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retasker(at)optonline.net
Guest

Posted: Sun Aug 07, 2011 4:12 pm Post subject: 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:

 	  Quote: 	
		   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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klehman(at)albedo.net
Guest

Posted: Sun Aug 07, 2011 4:34 pm Post subject: 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:

 	  Quote: 	

 <retasker(at)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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ainut(at)knology.net
Guest

Posted: Mon Aug 08, 2011 4:10 am Post subject: Pressure transducer for airspeed

I use the AMD 494/495.  Freescale also has some newer models that are 

even better, which I'm using for MAP, etc.



David M.



Paul McAllister wrote:

 	  Quote: 	
		   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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