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hallboyone / RaspberryLatte

A full stack suite to add smarts to a single boiler espresso machine using a Raspberry Pi Pico as the brains.
MIT License
15 stars 1 forks source link

Flow rate sensor is slow and not accurate at low flows #26

Open hallboyone opened 1 year ago

hallboyone commented 1 year ago

It could be replaced with something like this. However, this will require retuning everything, but this is probably okay since the flow control never worked great anyway.

hallboyone commented 1 year ago

I'm testing a new sensor (linked above) and have collected the following data. Screenshot 2023-07-12 at 5 15 19 PM The slope of the trend line is the conversion between the pulses and volume. The exact values to 6 decimal places are 

slope     =  0.009472
intercept = -0.054317

At low flows, the measurements get pretty noisy, but it should be good enough. As an added benefit, the pulses are much more frequent (about 60Hz at 0.5ml/s) so the discrete derivative will be able to update much faster.