This project is to build a Raspberry Pi sous vide machine that can be controlled via the web or via a walk up GUI interface. The main goal is to get something fully functional for cheaper than most commercially available solutions, which start at about $200, but also be extensible.
The main functionality of this Raspberry Pi is to turn off and on an external device, like a rice cooker or hot plate, via a solid state relay. A small screen and tactile controls provide for a walk up interface, and the power of the raspberry Pi is utilized for it to run a website that can control the sous vide machine.
Parts list for this project:
Raspberry Pi Kit, $85: http://amzn.com/B00G1PNG54
This may be able to be assembled for cheaper depending on any sales going on at the time, but your mileage may vary.
Rotary Encoders, $6.50: http://amzn.com/B00KHTLWU6
12v power supply for screen, $10: http://amzn.com/B00LLYYORO
3.5 inch screen, $17.57: http://amzn.com/B0045IIZKU
Cable to hook up to screen, $2: http://amzn.com/B008SO5LDQ
40 amp solid state relay, $7.99: http://amzn.com/B005KPIX9A
Heatsink for relay, $5.37: http://amzn.com/B005D6145G
Thermal paste, $3: http://amzn.com/B00006B8DX
Screws for relay/heatsink, $3: http://amzn.com/B00F32E42K
Temperature sensor, $11.99: http://amzn.com/B00EU70ZL8
Food safe heat shrink: $10: http://amzn.com/B0078S7DWA
Outlet, $1.19: http://amzn.com/B0015R9M2Y
Tupperware or other container (Suggest using one bought locally), $15: http://amzn.com/B007V4IWIU
A lot of these could be scavenged for cheaper than buying, for example using a CPU heatsink and metal screws as a heatsink instead of buying a custom made one. I also might have chosen a nicer, bigger screen in hindsight considering how much of a pain this all was.
First, the Raspberry Pi 2 will be the brains of our operation. You can use this as an emulator for old systems up to the Playstation and Nintendo 64, a full linux home computer, or to control low level hardware and input. These can be bought for $35, though expect the raspberry pi, breadboard, wireless dongle, power supply and SD card to cost at least double that.
The specific kit I got and used can be found here: http://amzn.com/B00G1PNG54
Once you get this kit, place the SD card in the slot, put the Raspberry Pi heatsinks on (I suggest cleaning the chips first with an alcohol swap), and put the Raspberry Pi inside of the enclosure. There is an included ribbon cable, which you will plug in to the raspberry pi and then to the breadboard adapter. Finally, plug the breadboard adapter in to the included breadboard. The power supply goes in to the micro USB slot, and while you can use any power supply try to make sure it is at least a 2 amp supply. Finally, plug in the wireless USB dongle.
You will need to image an SD card and hook the raspberry Pi 2 up to a keyboard, mouse and monitor via HDMI.
A complete guide of setting up the raspberry Pi can be found here: http://www.raspberrypi.org/help/quick-start-guide/
I highly suggest purchasing an SD card already imaged with NOOBS, new out of box software. You can find the guide on using NOOBS here: http://www.raspberrypi.org/help/noobs-setup/
Choose Raspian as your OS of choice, and once that is installed be sure to set your timezone and your keyboard nationality.