When you pick out the pressure sensors, the ones that output in volts are easy to use with PBP and PICs. 1 volt will be 0psi and 5 volts will be the high psi the sensor is designed for. This makes things easy for the ADC on the PIC.

Darrel must have some hidden meaning in his formula.

For every foot rise in a column of water 0.433 pounds at the bottom will show on a gauge. So...

H = P / 0.433 * SG

If you are new to hydrogen, please take a look at this
http://www.nationalboard.org/nationa...classic29.aspx
http://www.nationalboard.org/Nationa...query=hydrogen

Hydrogen is very hard to store safely. Not because of the flammability, it attacks the carbon in steel!!! Vessel failure!!!