Es(Pi)resso

fully modded Silvia, with digital pressure transducer, flow meter, driptray scale, variable pressure control (for pre- infusion), PID, e-ink display with info, live graphs and automated shots (based on desired graph).

http://www.espressomyespresso.com/Silvia/SilviaPID3.html

“Yes raspberry pi, got inspired by the “Es(pi)resso” project. Will share the write-up and code later. But tldr: raspberry pi, code in python, some SSRs, temperate sensor, pressure transducer, flow meter (spare part from a Nespresso machine), two 1kg load cells load cells under the drip tray (for scale).”

From left to right the buttons are: Standby (turns on the PID, and display), then the shot pull button (original button), hot water (original button), steam (original button), preinfusion button (turns on the pump at low power, around 2 bar, and when you turn it of it will keep the 3 way valve open for a bit). And then the Rotary encoder for selecting automated programs.

My reverse-engineered BOM:

• [ ] Raspberry Pi 3 or 4
• [ ] Rancilio Silvia
• [ ] ultrasonic sensor (to measure the distance to the water, and then calculate how full the tank is)
• [ ] 6x switches (9x momentary SPST, 3x On/Off Toggle)
• [ ] 1x rotary encoder w/ switch (CYT1100 Cylewet 5Pcs 360 Degree)
• [ ] Temperature Sensor: (Adafruit PT100 RTD Temperature Sensor Amplifier - MAX31865)
• [ ] 2 or 3 Solid State Relays
• [ ] pressure transducer
• [ ] leading edge digital dimmer (for preinfusion)
• [ ] Digmesa FHKSC 932-9521/B flow meter (EBay: $24.95)
• [ ] 2x 1kg Load cells
• [ ] 3” or 5” WaveShare e-ink display (needs custom firmware to update every 0.1 sec)

“I used a Digmesa FHKSC 932-9521/B which is the same as the once using in many domestic machines like those of Nespresso & Delonghi. They are extremely easy to interface, basically you count pulses and ~2000 pulses (you can calibrate this value yourself) corresponds to 1 liter of water in.

End of the cup ml is different then the grams out as a. Some water will remain in the puck, b. We are measuring what goes in, so we fully ignore the extracted coffee, c. The solenoid valve will release a tiny amount of water at the end of a shot directly in the drip tray. So i just add an offset for these (and luckily these are very consistent) and let is stop when my cup reaches xxgrams.”

Oh yes, haha keep forgetting that mod, I use an ultrasonic sensor measure the distance to the water, and then calculate how full the tank is (didn’t want any electronics touching the water).