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Bluetooth Pressure Gauge for the Sage/Breville Barista Express.
If you don't mind a bit of manual tweaking, there are easier (and cheaper) ways to control brew pressure than via pump speed adjustment: https://www.instagram.com/p/BKInEJFB6WP/
A inline restrictor in the brew path doesnt sound like a good idea. You may as well have a double wall basket. Probably a double wall basket would be a better restriction
Or is the restrictor going as a bleed screw and dumping off pressure where a opv would go?
The first batch of components have arrived for the project. Also got word from the FAB house that the PCB:s are manufactured and sent.
Done with the firmware for the BLE112 module, and the first version of the iOS App for iPhone.
Actually I will be testing several alternatives for temperature measurements. The module will have both analog and I2C inputs.
LM35DT
MLX90614
TC74
Below the "cheaper, no name" ±1.5% FS accuracy Pressure Sensor, have also ordered a Honeywell PX3.
A inline restrictor in the brew path doesnt sound like a good idea. You may as well have a double wall basket. Probably a double wall basket would be a better restriction
Or is the restrictor going as a bleed screw and dumping off pressure where a opv would go?
It is upstream of the basket (in fact, in my case its on a bypass line around the pump). No coffee passes through it, not comparable to a double wall basket at all.
Also, you can't "dump pressure" - you can divert flow though
Ok. Bypasses around pump. Its a poor replacement for a opv. Imo.
If your grinds determine a 12 bar extraction and your valve is adjusted to 'dumping pressure' to 10bar, then you are dumping 20%. Midway through the extraction, when the pump could be delivering 10bar, you are still bypassing 20%, so delivering only 8bar to the puck.
Even in the link if you check the pics the poster was unhappy with the arrangement and was trying to mechanise the tap operation. It looks like he gave up on that as well and was going to try something else.
Maybe the bypass in conjunction with a solenoid to shut the bypass when pressure drops. But a opv isnt that expensive or hard to set up.
Sorry to divege from the op topic.
Looking forward to seeing this work out as a cool project
Ok. Bypasses around pump. Its a poor replacement for a opv. Imo.
If your grinds determine a 12 bar extraction and your valve is adjusted to 'dumping pressure' to 10bar, then you are dumping 20%. Midway through the extraction, when the pump could be delivering 10bar, you are still bypassing 20%, so delivering only 8bar to the puck.
Even in the link if you check the pics the poster was unhappy with the arrangement and was trying to mechanise the tap operation. It looks like he gave up on that as well and was going to try something else.
Maybe the bypass in conjunction with a solenoid to shut the bypass when pressure drops. But a opv isnt that expensive or hard to set up.
Sorry to divege from the op topic.
Looking forward to seeing this work out as a cool project
I assure you, the poster is still using the setup. Whilst not perfect, it's far superior to an OPV, which is a poor replacement for a control valve (and is still fitted to the machine BTW).
You can't adjust the flowrate mid-shot with an OPV...
The guy is obviously a brainiac. I looked through his post web page and instagram. Pity he has no article about the bleed valve on his bz99. Would love to learn more on this subject
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