Completed Project. Total cost was somewhere around $350.00. It took about 9 months (partly because I bought and remodeled a house and had a kid..)
Basically, I'm a mechanical engineer who designs plumbing and fire protection system. My invention tests the building's domestic plumbing infrastructure on pre-war NYC co-op buildings and allows me and my company to determine if we can fulfill the owner's requirements for the plumbing before demolition happens. It also allows us to inform the owner if the plumbing system will need any booster pump systems, hot water heaters, etc., that are typically not in the budget, early on in the project before they have committed a cost of the renovation in their heads. Otherwise, if we do not alert them of any issues asap and wait to see what happens, my company will end up picking up the tab for redesigns and maybe even equipment costs. $$$ out of our pocket = unhappy boss.
I can also use this to help with booster system diagnosis and other random issues.
So basically the performance and specs are:
Medium Temp 50*-140*F
Accuracy +/- 4%
Pressure Drop Across device = negligible
Memory = 4 test results stored in non-volatile (can be as much as 80)
Dimensions 13"L x 6"Dia
Weight = a hair over 5 lbs.
Uses two Seeedstudio flow sensors in parallel and a Barksdale pressure transducer. All three sensors are reporting back the a Arduino UNO. Display is a Sparkfun serial LCD and the pressure transducer amplifier is made from a TI INA-125. Has a battery monitoring circuit so I don't get caught with dead batteries. Feathers a filtered, fused power supply. Case is made from .125" thick clear plexiglass with .25" thick plexiglass end caps. I have had nothing but problems with every part of this project but learned a ton. Overall, not a bad little project, lol.
Next on the list is to change out the batteries for rechargeables and a charging circuit port to keep untrained hands out of my baby. I also want to expand on my battery monitor so it notifies the user of low batteries as well as dead batteries (relatively speaking)
I make it so that even the least experianced person could run the test after a quick explaination. If the GPM reads zero, the record button will only record the static (non-flowing) pressure. If the GPM is more than 0, than the record button will record the residual (flowing) pressure and at what GPM. You can go back and review saved tests, clear the memory or "logs" one by one or all at once. I have a extra secret diagnosis menu which will allow me to see raw data for calibration.
Let me know what you think or if you have any questions.