A project log for Raspberry Pi Wet Incubator/Sous Vide/Slow Cooker

A web and locally controlled sous vide and slow cooker, now turned in to a laboratory water bath/DNA PCR cycler.

staticdet5staticdet5 07/07/2015 at 15:130 Comments

This project has been on a slow burn for awhile. Life intrudes.

Two weeks ago a friend contacted me from overseas, and asked for the whole set-up. Slow cooker, beat up case, everything. Their multi-thousand dollar incubator couldn't handle the heat and environmental conditions. Their lab is fortunate to have a trained microbiologist, someone who is actually able to make real use of this type of equipment. Frequently it's not a matter of having the equipment, you need the skills to use it. It's even better when you have people that can innovate to the equipment that is there.

I put a final polish on the code, and shipped it. My friend gave up his cellphone charger, and wired the crockpot for the local power (I'm worried about this, as I didn't check anything about this. I know the relay will take it).

I didn't put the code into a repository. We're trying to figure out how to remedy this now. I'm freakin' furious with myself for doing that. I'm checking my chips, and scouring moving boxes looking for old code.

OK, a water bath incubator is easy. Honestly, you set the temp, and keep it there. The code updates that I did kept a minute by minute log of the average temperature, and archived them for a month. The users are setting the temp through a command line interface, but I'm betting that the temp is being maintained at 98.6F/37C. The lab is air conditioned, and supposedly on an emergency generator. From the sounds of things, the emergency generator is what killed the incubator. The dirty power fried the control system or something.

The next step is to incorporate a cooling system into the mechanism, in case the air conditioner fails. Once the cooling loop is incorporated, this project evolves into a DNA PCR machine (A feature request).

PCR stands for Polymerase Chain Reaction. In layman's terms it is DNA amplification. In theory, give me a single cell, and I can replicate that DNA. There is nothing stopping you from taking the 3.6 picograms from a human cell, and replicating it in a machine until it is something you can see with the naked eye.
To do this, you have to mix the sample with DNA primers, put it in a machine to heat it and cool it in a controlled fashion. The goal is to get the DNA to uncoil, meet up with the DNA primers completely, coax it in to reassembling, and then repeat the process. Quickly. Every time you repeat the cycle, you double the DNA.

Now, there are some other cool tricks you can do with this, beyond simple replication, but that's for the guy in the lab to do. I haven't done this for close to ten years.