buestad Senior Member Joined: 22 Nov 2013 Posts: 20 Location: Norway Expertise: I love coffee
Espresso: Rancilio Silva Grinder: Rancilio Rocky
Posted Sat Nov 23, 2013, 1:27am Subject: Electronic pressure transducer
I am thinking about modding my Silvia with an Arduino board, and one of the inputs I would like to have is brewing pressure. I don't want to make any external mods to my silvia so I want to read off the pressure using my phone through Bluetooth communication, therefore the electronic pressure transducer.
Has anyone ever ever fitted a electronic pressure transducer to a silvia or any other equivalent machine?
I used an AST 4100 for my Silvia. Nowadays there seem to be plenty of lower cost alternatives like the Omega that jonr mentioned (although these alternatives are probably a lot less durable than the industrial-type AST).
How to measure flow? isn't the grouphead mounted directly on the boiler?
I just had a $10 digital tire pressure gauge die. I'm tempted to remove the sensor and try it for espresso. On the other hand, I think it is flow that matters most.
I wouldn't be surprised if future espresso machines do away with the OPV and just use a flow sensor and pump power control. Given flow and power being sent to the pump, you can roughly estimate pressure based on the pump curves.
Look at the specs: Working Temperature: -40—+120ºC; Compensation Temperature: -20—+80ºC;
Maybe it will work between the pump and the boiler. I don't know how hot it gets there, but when steaming the boiler goes up to 140-150ºC. I've been searcing around, and the transducers handling more than 120ºC is REALLY expencive...
Have you looked into the Auber pressure sensor? it's available with ¼ and ⅛" fittings, and since one of it's intended uses is in a running internal combiustion engine, it probably can handle the temps.
You can also contact AutomationDirect. I picked up a motor control unit from them, they have good customer service, lots of products, very prompt shipping and great prices on industrial grade equipment. It is not all from China second tier makers either, I do have several Auber controls but the ... quality .... of the parts is not industrial grade, not like the stuff at Automation Direct. http://www.automationdirect.com/adc/Home/Home Give them a look anyway, looking is free and you might find something that you like better. YMMV!
In real life, my name is Wayne P. Anything I post is personal opinion and is only worth as much as anyone else's personal opinion. YMMV!
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