I'm hoping to tap some collective wisdom from the mbed group.

I need to monitor water pressure up to about 175 psi for an upcoming mbed project.

Commercial fluid pressure sensors are very spendy. Any clever suggestions for alternatives?

I'm thinking along the lines of an automobile's oil pressure sender or a digital air pressure meter for bicycle tires... Any other suggestions would be appreciated.

Thats 1.2MPa or 11.9 bar ( for the not inch people in the world :) Automotive oil pressure sounds good.

What is the accuracy you expect ?

maybe : http://www.ladyada.net/learn/sensors/fsr.html

Hexley -

I would love to take advantage of some of the mass produced sensors used in automotive, such as the pressure sensors. But the details of these sensors must be some of the best kept secrets on the internet. After reading postrequest I spent a couple of hours looking into this and came away with nothing!

Someone has to know where to get the details.

Mike

I found this info: /media/uploads/driedee/bosch_pressuresensor_.pdf

on this site with more automotive sensors http://www.mksautobusiness.fi/page_sensors_pressure.html

Here is a thought. If you had a long resistor that was sensitive to pressure then you could take a piece of rubber hose and wrap the resistor around it. As the pressure increases then the diameter of the hose would increase and you may be able to measure your pressure. Perhaps this device from Sparkfun could be wrapped around something. http://www.sparkfun.com/products/9674