For beginners or others looking for easy to use air pressure sensors, may I recommend the Freescale/Motorola MPX series of air pressure sensors. I have used several of them (MPX4100, MPX4115, and MPX5100) and have found them very easy to use with the A/D input of Picaxe, PIC, AVR, and other lines of microcontrollers. They each come in several subscripts (A for absolute, D for differential, etc) and you can find all of the information from their datasheets and online searches. The main things I looked for were full scale output swings to near the 5 volt rail (4.25V+). This indicates internal amplifiers and no need for external differential amplifiers (pain). Some (MPX4115A) are specifically for applications such as altimeters and such and some others (MPX5100) specifically describe their use with microcontroller A/D inputs. With mine, I simply use the Vcc, Ground, and V+ output. You can buy models that are compensated or uncompensated. Most of the data sheets give transfer functions on how to convert the analog outputs to kPa and such. Also, if you want, with these simple and straighforward analog outputs, you can even hook them up to a simple multimeter, get the direct voltage reading and convert in your head or on paper. I love these things!
By the way, you can pick up these gems at such outlets as Digikey, Mouser, Newark, etc. They usually run in the $10 to $20 each price range.
By the way, you can pick up these gems at such outlets as Digikey, Mouser, Newark, etc. They usually run in the $10 to $20 each price range.
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