Sous-vide and Yogurt Maker v2.0

15 November 2014

We've been using our Sous-Vide temperature controller a lot lately to make yogurt, and it has attracted the curiosity of our roommates and colleagues. To make it more user friendly and easier to build, I tried to design a more finished product with easily sourceable parts.

Here's the list of parts:

McMaster 1/4" Acrylic Sheet for the box
Amazon Acrylic cement to assemble the box
Amazon Arduino Nano Board
Amazon Waterproof Temperature Sensor
Amazon Backlit LCD screen
Amazon Relay Module
Amazon Panel-mount Power Socket
Mouser Panel-mount potentiometer
Mouser Panel-mount Switch

I tried to make the box countaining all these parts as small as possible, so it was really helpful to design it in Autodesk Inventor first and see how to best fit them. Below are renderings from this software showing how it looked like on the computer.

And below is what it looked like after assembly. I chose to keep access to the micro usb of the arduino for programming and debugging purposes, but the next version will all be powered using one cable. The power socket is the regulated output to which the slow cooker (or other appliance with an electric heating element) is plugged in, and the temperature sensor comes off the top of the box, next to the LCD screen. The front of the box has a push button for navigation and a potentiometer for adjusting Temperature, Time and PID coefficients.

The second half of the work was writing a more user friendly and more flexible firmware. I added a timer and simplified the menus by placing the PID parameter tunings are placed in an "Advanced settings" submenu. As in my previous post, I tried to use only one button to move around, by distinguising short and long presses, SP and LP as shown in the menu diagram below.

The Arduino code is available on my Github page, and should work as long as the same temperature sensor and type of LCD are used and the pin numbers are adjusted.