Water Bath Thermostat

By Sean Michael Ragan
Category: Food & Beverage, Computers & Mobile
Time Required: 4 hours
Difficulty: Moderate

This project was inspired by Cooking for Geeks author Jeff Potter’s quick DIY sous-vide hack. My plan, initially, was to just hack the controller into an enclosure with an A/C outlet, the idea being that you could just plug any heater you wanted into the outlet.

Looking around for cheap temperature controllers, however, I happened across the STC-1000 on eBay for $25. It’s not PID, but I was betting it would still be accurate enough for almost any practical purpose. And since the STC-1000 has both heating and cooling functions built-in, the logical next step seemed to be to split a single A/C outlet so that you could plug a heater or a cooler (or both) into it and use it for all kinds of stuff.

The STC-1000 will regulate at any temperature between the freezing and boiling points of water, which opens up potential applications in chemistry, aquaculture, zymurgy, hydroponics, cooking, etc., etc.

Parts
/
Tools

Adhesive-back mailing label
Crimp-on Female Disconnect
Decora-style AC power outlet
Heat-shrink tubing
IEC 320 C14 AC Power Connector
Insulated binding post
Junction box
Power cord
Solder
STC-1000 Temperature Controller
Wire

#0 or #00 Philips Screwdriver
C-clamp
Coping saw
Countersink
Drill and bits: 3/16"
Labelmaker
Pliers
Printer
Soldering iron
Wire cutter/stripper

Steps

Step #1: Prepare sensor jumper cable

Cut a 4" length off the end of the STC-1000's bundled temperature sensor cable, and separate and strip the cut wire ends.
Remove the ring terminals from the binding posts and bend each at a 90-degree angle using two pairs of pliers, as shown.
Twist the stripped wire through the holes on the bent up leg of each ring terminal, forming a strong mechanical bond before soldering.
Flux and solder the ring terminals to the ends of the cable.

Conclusion

Sous-vide eggs, which are cooked in the shell, are a great place to start experimenting with this controller. I find an hour at 65C gives an absolutely perfect soft-boiled egg.