As Newton said "If I have seen further, it is by standing on the shoulders of giants."
First Cannonfodder hacked* the e61 thermometer adapter, then Eric Svendson brilliantly engineered the e61 Thermocouple
I've slightly extended their work with the Digital Pressure Adapter :
Brew Pressure during an actual shot.
Pump Pressure on the Vibiemme on a blind basket.
Pressure on the Blind Basket. (Note the droplet at the gauge / SS-TA junction. The mating of the two 1/4NPT threads is rather poor. The standard two wraps of teflon tape is not cutting it here. EDIT: SwageLok SS-TA Adapter defective. Replacement does not leak with Teflon tape.)
There are a multitude of gauges available. As this is a seldom used device for a home barista, I opted for the cheap and cheerful Dwyer DPGW-09
0-200PSI / 13.8bar 500ms update. More sophisticated gauges with Min / Max, faster response, logging, etc. can be found by searching for 'Digital Pressure Gauge' on the web.
The adapter is a SwageLok SS-2-TA-7-4
. Eric offers the adapter as part of his 'kit'
Which brings us to the sermon:
I'd dialed in the brew pressure long before I embarked on this escapade. The impetus behind the expenditure is to be able to accurately reset the pressure should I ever disassemble the OPV and perhaps help a friend or two dial in / diagnose a machine. The actual numbers are freaking meaningless, so I don't want any PM or posts saying I set my SS-Itai to 8.22bar and the coffee sucks.
The extra 2d:
This adapter allows actual pressure measurements during an actual shot you can taste, which according to John Ruskin "Taste is not only a part and index of morality, it is the only morality."
*Edit : 'hack' is the highest possible praise : a person who makes things work beyond perceived limits through their own technical skill.