Kitchen Hacking: Cafeino Espresso Automator

The Cafeino 1.0 takes a cheap, manual $100 espresso machine and installs the precision temperature control of a $2000 commercial machine. This involves tapping into mains A/C voltage and modifying the machine's internal boilers.

Replacing Mechanical Thermostats with PID

Cheap machines use a "snap thermostat" that wildly fluctuates the water between 85°C and 105°C, resulting in sour or burnt coffee.

1. The Sensor: You rip out the old thermostat and bolt a MAX6675 K-Type Thermocouple or a high-temp thermistor directly to the exterior of the aluminum boiler.
2. The Control: You wire the machine's heating element to a Solid State Relay (SSR) controlled by the Arduino.
3. The Math: The Arduino runs the PID_v1.h library. It rapidly pulses the SSR on and off (e.g., ON for 1s, OFF for 2s) to "park" the water temperature at exactly 93.0°C and hold it there flawlessly.

Automated Extraction Timers

Once the temperature is perfect, you can automate the water pump.

• You wire the vibration pump to a second SSR.
• The user presses "Brew".
• The Arduino turns the pump ON for a 3-second "Pre-infusion", pauses for 3 seconds, and then runs the pump for exactly 25 seconds for a perfect double espresso extraction!

Hardware Components

• Arduino Uno or NodeMCU: The PID brain.
• MAX6675 Thermocouple Module.
• Solid State Relays (SSR-40DA): Must be SSRs, standard mechanical relays cannot switch fast enough for PID control.
• I2C OLED Screen: To display the rising temperature curve.
• (Warning: Touching mains power can be fatall. Ensure the machine is unplugged while wiring).