Time to go autonomous.
Growing tired of swamp cooling for fermentation “temperature control” I’ve decided it’s time to invest in the widely popular 2-stage STC-1000 “ebay” temperature controller. And with a spare mini-fridge from college simply sitting in the detached garage- why not, right? This project in it’s entirety was inspired by the HomeBrewTalk.com community and countless user write-ups with similar projects (hey- credit where credit is due). So let’s build this damn thing! Here’s what you’ll need:
- QTY 1 – STC-1000 Digital Temperature Controller ($19.99 Ebay)
- QTY 1 – 120V Alpinetech 22mm Blue LED Indicator Light ($4.95 Ebay)
- QTY 1 – 120V Alpinetech 22mm Red LED Indicator Light ($4.95 Ebay)
- QTY 1 – 7″ x 5″ x 3″ Project Box ($7.49 RadioShack)
- QTY 1 – 10′-0″ 14 gauge replacement power cord ($13.97 Lowe’s)
- QTY 1 – 115V-1Phase-15A Black Receptacle ($1.99 Lowe’s)
- QTY 1 – Bag of 6/32 Nuts ($1.18 Lowe’s)
- QTY 1 – Bag of SAE No. 6 flat washers ($1.18 Lowe’s)
- QTY 1 – Black Outlet cover ($0.39 Lowe’s)
- Wire strippers/cutters
- Screw driver
- Dremel (or other cutting tool)
- Power Drill
- Step Bit
- Needle nose pliers
Total Cost $56.09
Depending what you have in your garage- you may need to purchase additional incidentals such as wire-nuts ($2.58/bag), Dremel cutting tools ($6.18/cylinder), etc., etc. however I’ve excluded these items from the above parts list as most DIY-ers will already have these items on hand.
The LED indicator lights are completely optional. The reason I (and many others) choose to include indicator lights is to have a clear visual display communicating whether the controller is calling for either cooling (blue) or heating (red). These 120V LED lights from Alpinetech are truly a perfect fit- small enough to fit into a project box yet big/bright enough to see from across the room, affordable (at $4.95/each), and most importantly.. the correct voltage (120V/1Phase) for this application. But it is a place to shave off $9.90 +S/H from your bottom line- just sayin’.
Step #1 Time to get into the weeds; the wiring diagram.
So… If you are now lost… STOP! And- to be fair… I’m also not an electrician and electricity is extremely dangerous. Consult a certified and-or licensed electrician to check your work if in doubt. This write up is a guide (and not the gospel). Do not risk your life to save money as there are several commercially available pre-assembled temperature controllers in today’s marketplace.
Step #2 Break the bridge.
A very important step in the above wiring diagram is to break the bridge (-or tab) connecting the two hot terminals on the receptacle. By doing so- it allows each outlet to be positively charged independently from one another. -Or for this project- it allows you to have one outlet for cooling and one outlet for heating. I was able to remove the bridge with neelde nose plyers and a little “persuasion” as shown in the above images. No need to remove the bridge on the neutral side as the receptacles can still share a common neutral connection thus reducing the number of wires needed. (See- saving both time & money already!)
Step #3 Templates are amazing.
Once you’ve figured out how you want the finished controller assembly to look create a template(s) (and make copies). A simple template will save time and limit ones frustration while cutting out the openings in the project box. Hey -it’s not brain surgery- but a little precision never hurt anybody.
Step #5 Let er’ rip!
Begin cutting out the required openings. Remember- a hole can always get larger… however making a hole smaller requires a magician. Cut conservatively.
Step #6 Confirm opening sizes. Repeat Step #5 as necessary.
Step #7 Drill a hole for the power cable & temperature probe. Time to begin the wiring process.
Now that you’re an expert cutting openings in the project box using either a large drill bit or a step-bit cut a hole(s) for both the power cable & temperature probe. No need for a template here as you are now an expert project box surgeon- remember?
Step #8 Moment of truth…
Well it looks the part… now it’s time to test out your wiring skills… This is also a great time to confirm both outlets are truly operating independently. When “cooling” is activated- the receptacle wired for “cooling” should read ~120V and the “heating” receptacle should read 0V. The reverse is true while in heating. The below screenshots should help illustrate this test.
Step #9 Close the project box and have a victory brew.
It also helps to have a Celsius to Fahrenheit conversion table. I found mine via our friends at homebrewtalk.com:
Lessons learned? -Of course.
1) The screws to secure the receptacle to the exterior wall of the project box simply weren’t holding under the pressure of plugging/unplugging power cords. A quick fix was to use #6 flat washers & #6-32 hex nuts to keep the receptacle mounted in it’s proper place.
2) Was cooling the left -or the right receptacle? Label them to save yourself the headache of tracing your bird nest of wires.
Now time to build the fermentation chamber 🙂