pressure Sensor to measure 50mmHg absolute vacuum pressure

Hi, everyone. I need an arduino compatible sensor to measure between 30 - 50mmHg absolute pressure. Can anyone recommend anything ? The scale doesn't have to be in mmHg as long as it can give an equivalent of these values. Thanks.

Your topic title and the body of your post are somewhat ambiguous. Did you mean... a pressure that is 50 mm Hg below atmospheric pressure (a weak vacuum... -50 mm Hg "gauge")? Or did you mean a pressure that is 50 mm Hg above absolute zero pressure (a strong vacuum... +50 mm Hg "absolute")?

Anyway, to find the appropriate sensor, go to Digikey or Mouser or.... and search for a pressure sensor with the appropriate pressure range that outputs the result in SPI, I2C, 0 to Vcc, or 4-20mA.

Or, google vacuum pressure sensor arduino and see what other people have done.

The latter is probably a better approach for you, since your statement "The scale doesn't have to be in mm Hg..." indicates a lack of understanding about sensors in general and how an Arduino is used with sensors.

Thanks, DaveEvans for the answer. truly, I am new to the use of Arduino. however, I meant +50 mmHg psiag which is a strong vacuum. I believe that was clear enough from the question. I have gone through Google before even posting on the forum and I couldn’t find any sensors that could go that low. As regards my lack of understanding of sensors in general, what I meant by the scale not being in mmHg was that if the output was in kPa or bars, it didn’t matter as long as I got the required pressure range. Thanks again, DaveEvans

An Arduino can convert the output voltage of an analogue sensor into an A/D value.
Or directly read a digital sensor. That value might be 0-1023.

Not so good for humans to understand, so that value is usually converted to kPa, bar, psi, mmHg, or whatever.
That part of the code is up to you.

However, I meant +50 mmHg psiag which is a strong vacuum.

“psiag” is not a standard unit. It’s either psia (pounds per sq inch relative to absolute zero) or psig (gauge pressure…relative to atmospheric), not psiag. And they should not be combined with mm Hg. (I corrected my first post…shouldn’t have combined mm Hg, psia, and psig!)

Anyway, Honeywell makes a sensor with a range from 0 psia to 15 psia. You’d be using about a 1/15th of the full range, but maybe that’s ok for you.

Thanks DaveEvans and Wawa for the insights. Truly appreciated, however, DaveEvans, where would you recommend I get the Honeywell sensors. Also, is there a model number or name that you can recommend I look for in particular? Thanks.

Please, look here.

The output of the sensor is in mV; the sensor is not factory calibrated. This means that you have to calibrate it in the field using two known points to find the response equation of the form y = mx+c considering that the sensor is linear and real.

Honeywell make lots of sensors. They make lots of conflicting claims. They can't all be "super high accuracy better than all the others we make". I have used a few different ones from them.

I have also used a few different MPX and MPXV series sensors from Moto-Free-WhateverTheyCallThemselvesNow. They are a little simpler to work with. I did find they need regular re-calibration.

There are a number of sensors to stay away from. Anything with a millivolt output is going to be significantly more difficult to work with. Get something with 5V analog output or I2C output.

Thanks everyone for the help. I'll keep you all posted as regards the progress of my project. You've all been of tremendous help.