Friday, August 5, 2011

Time to cook, timing to cook

For awhile I wanted to get into Sous Vide cooking, because it is

  1. cool
  2. involves tinkering with hardware
  3. and is featured in the book "Cooking for geeks".
There are numerous instructions to be found on the web, but somehow, because it is half of the fun, I decided to start to design my own solution. Partly because our local hackerspace "baustelle Hamburg" once tried to organise a Sous Vide cooking event (but we were just getting started with everything, so we had to cancel it - but we have a nice poster!).

Essentially Sous Vide cooking involves food which is sealed in a vaccum bag and put into water of a precise and predetermined temperature. Professional cooking equipment can be very expensive because you need a good temperature control, and since it is not really a mass market, I guess there is quite a big profit margin.

I will either use a rice cooker or a slow cooker, which needs to be modified in order to keep the temperature. To achieve that, I use a microcontroller (Arduino) and a TRIAC based switch to turn the rice cooker (or whatever) on and off using a PID controller.

Essentially it all boils down to choosing the right ingredients. You need a good PID library, a versatile Arduino which is small enough to fit onto a PCB provided by tinkerlog.com and some electronics skills. I already made some prototypes on a bread board and I am currently designing a PCB board, which is not ready yet, but should somehow work.


  The biggest problem with this solution is that it uses a fairly lame temperature sensor. The LM 235 has an accuracy of about +/- 1 degree and I am still looking for a cheap and easy alternative. Or I design the sensor in a kind of modular way, so that I can make experiments with other sensors.

BTW, I never can make up my mind which blogging system I like more: this one here, which is driven by blogger or posterous where you can have a look at http://justjoheinz.posterous.com

Ah! And if you have any kind of your own Sous Vide stories, please share!

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