pressure sensor, where from ?

[max_imum2000]

hello
i am looking for some kind of pressure sensor to measure vaccum level, the range will be max 30Hg.
what should i look for ?
i will need to interface it to a pic uc, so its better to give a logical output (voltage within range or so)
thanks

 

[Russlk]

search for "pressure sensor" at https://www.mouser.com or https://www.digikey.com you will get multi hits.

 

[Oznog]

i will need to interface it to a pic uc, so its better to give a logical output (voltage within range or so)
thanks

They pretty much all give a voltage output. However the complicating factors are:
1. differential output- all transducers actually start as a differential signal, that is, there's two voltages and the only thing that matters is the voltage difference between them, the value of either one versus ground is meaningless. Some devices have a differential amplifier on them which changes it so the output is versus ground. Otherwise you've got some issues to look at (this is not a big problem).
2. high output impedance- most PICs are designed to read a source with an impedance under 2.5K ohms. Unless it has an internal amp, most devices will be more than that. You'll need to buffer it with an op amp.
3. Small signal level- you want to select a device with a scale on the level you'll use it. For example, if you want to measure a very slight vacuum, a sensor which gives a full scale reading for a total 0 PSI vacuum may give such a small voltage at the slight vacs you intend to read that the sensor's offset errors will swamp the result and/or the PIC's ADC may introduce significant errors.

Freescale Semiconductor is a popular mfg of pressure sensors.