Very useful topic, just started playing around with the same ebay transducer that the thread was started with.
We work in bar, so my formula looks like this, since the working pressure of the transducer is 12 bar:
outputBAR = ((transducer - 102) * 12 / 819);
I'm using a MEGA 2560 and I would like to make use of the internal 1.1V reference to make the reading more accurate, but I'm not sure how to change the formula above to use the 1.1v ref. instead of 5v.
I have thrown around multiplying and dividing with 5 and 1.1 in several places in the formula but I've ended up with either 1 bar or 1.2 bar when its meant to read zero.
Help would be appreciated.
Hein