Arduino controlled Milk Heater And Stirrer

This is the controller firmware for the project that is extensively documented at :

https://www.skynext.tech/index.php/2022/12/27/design-and-fast-prototyping-of-a-milk-curd-stirrer-and-heater-using-arduino/

This project is intended for the dairy industry and small farms. It can be used to ease the processes of :

• Pasteurization.
• Cheese making (some steps are manual, like curd cutting, for now)
• Milk jam making.

It can be used for fruit jams, although be sure to use properly passivated stainless steel for the hardware part of the implementation, and adapt thermodynamic constants.

Features :

The firmware performs the following functions :

• Temperature management through PID control, rise and temperature hold ramp management. That is, you can program it to get from temperature T0 to temperature T1 in a specified amount of time, provided the hotplate it drives is powerful enough. It uses a SSR relay to control the hotplate duty cycle.

• Stirring on/off by controlling a high torque AC motor through a simple relay.

• Measuring liquid quantity through a VL160x laser range finder. Making valid measurements requires careful module & cover placement and proper calibration ! Refer to the main project page mentioned at the beginning of the article for more info.

• Measuring contents temperature through a probe sheat with a Dallas DS1820 sensor.

TODO

Software :

• Enable audible power-off warning through Vcc voltage reading.

• Make the project Arduino UNO R4 compatible and add wifi telemetry & remote control & remote program definition/inspection.

• Show program caption on the Lcd keypad when selecting the program.

• Streamline code-bundled program definitions (into FLASH).

• Add the possibility of inputing custom programs through the LCD keypad and store them in the EEPROM.

• Add other kind of liquids support (and their thermodynamic constants).

• Additional temperature measurement code (ambient & motor).

• Rotor lock detection code.

• Motor CW/CCW rotation control.

• Code cleanup and factorization, reducing RAM footprint with string tables and use of F() as much as possible.

Hardware :

• Larger capacitor for loss of power detection.

• Rotor lock detection (the range finder could be used, or a hall sensor / magnet assembly or variable reluctance sensors).

• For complete motor protection, current sensing could be added.

• Two additional temperature sensors : one for ambient temperature and another for AC motor temperature measurement for overheat protection.

• Add cylindrical heatsink on top of AC motor.

• Add additional wire from motor relay to motor for switching between CW/CCW motor rotation.

• Add curd cutting grates to the stainless steel paddle assembly.