Posted on

Sous Vide Update

The sous vide controller is beginning to take better shape than the prototype on the breadboard.  Note, this one still has a fully configurable analogue stage.  The wheatstone bridge and the op-amp gain can be changed by swapping out resistors.



The meals have also progressed beyond soft-boiled eggs.



Posted on

Spectrum 2016!

I just spent the past two days helping out at our booth at Spectrum 2016. Spectrum is a triennual show put on by the U of S College of Engineering students.  The people attending on Thursday and Friday tend to be predominantly school field trips.  It was great to meet kids who were enthusiastic about making things.

The show continues on Saturday and Sunday, so please come visit our booth and chat with us about making things and maker culture.

IMG_3125 IMG_3123 IMG_3124

Our display consists of a variety of projects that Techworks members have made.

Of course, there is a ton of other cool stuff to see, so budget at least a couple of hours to look around.  Kilobots XXXII will also be holding their event in the Hardy Lab on Saturday and Sunday, so if that’s your thing, make sure to budget even more time to watch the mayhem.

Posted on

Temperature Control (Sous Vide)

I have been talking about this for ages… threatening to build it… even ordered parts.  But, it wasn’t until a couple of weeks ago when Drew brought his Sansaire over and cooked some eggs for us that I finally got the motivation to start work on this project.

There are 101 ways you could do this.  I’m going for cheap.  My temperature sensor is a super-cheap PT100 PTC sensor.  I am running it in a wheatstone bridge connected to a differential amplifier tuned to get the best resolution out of the temperature range I’m interested in. (49C – 74C)  The output of that goes to a Nano clone, which currently only turns a Solid State Relay on and off.  (I plan to use PID in the future)  The relay turns a slow cooker on and off.  This tiny one really isn’t hot enough, but I’m giving it a try today.



I am monitoring the whole thing over the USB/Serial port with a quickly hacked together windows application.  Future plans including adjusting the setpoint and tuning the PID from this application.



So, in about an hour, I should have some perfectly cooked eggs!




It worked!  These were cooked to 64.5C for one hour.
IMG_20160106_185521 IMG_20160106_185614