21 October 2013
Monday, October 21, 2013 By Mike McRoberts Arduino, controller, diy, Hack, PID, sous vide, temperature sensor 2 comments
I had seen plenty of websites or videos of people making their own sous vide cookers so thought I would give it a go myself. If you don't already know, sous vide is a method of cooking food in sealed bags in a water bath with the water held at a very precise temperature. The food is cooked for a long time and means the food is cooked perfectly evenly throughout instead of cooked well on the edges and not so well in the centre. A perfect steak for example would be the exact shade of pink you wish from edge to centre. As a huge steak fan and having had some fantastic steaks in expensive restaurants but been unable to reproduce them at home I wanted to try this out.
I already had a slow cooker and at first intended to hack it for temperature control. But after using an Arduino and a DS18B20 temperature sensor I was able to determine it was capable of reaching the target sous vide temperatures easily and beyond. So I decide to make an external temperature controller box instead. I was originally going to use an Arduino and a relay, but found out you can buy temperature controllers cheaply on eBay for a lot less than the cost of an Arduino and a relay. So I bought a cheap PID temperature controller for about £10, a project box and a few other parts and set about making the unit.
These units are fully controllable with either a high or low temperature setting, temperature alarms, time delays and so on. They are very easy to wire up (despite the crappy instructions you always get with Chinese made electronics).
The steak I cooked on the very first time I used the unit was cooked perfectly throughout and was, without exaggeration or bias, the most tender and delicious steak I have ever had outside of a top London restaurant. Even my partner, who was very sceptical about the whole thing, admitted that the steak was the most delicious she had ever had and was very impressed. For a total cost of around £35 I have made my own sous vide cooker and cooked an amazing steak without shelling out the £100's it would normally cost to buy a domestic sous vide cooker. I will definitely be cooking all of my steaks the sous vide way from now on.
A lot of people use rice cookers instead of slow cookers as the thin walls mean you are able to control the temperature more precisely. If I didn't already have a slow cooker I would have purchased a rice cooker. However, the slow cooker works extremely well also.
As I made an external controller instead of hacking the slow cooker this means the cooker is still fit for purpose and is still safe. Also, I can plug anything I want into the unit and give it temperature control, such as a heater, fridge, freezer, home brew kit, aquarium, etc.
I've made a video (see below) that shows the full build and if you want further information then contact me on Twitter, G+ or Facebook using one of the methods listed at the end of the video.