I had a notion to try some sous-vide cooking. I have a simple 3-setting crockpot and just needed a temperature controller. There are plenty of instructions available for how to do this: I started with this one from Instructables.com. I planned to follow it exactly but then saw I could make some mods, like skipping the C14 plug - too much hassle and why would I need to disconnect the power plug? I also mounted the power outlet vertically - horizontal open power sockets in an environment with liquids makes me nervous.
The most popular controller is the STC-1000 available under many brands (or unbranded) and used for aquariums. It's dual-channel and will control both a Heat and a Cool source, one to keep temperature above a threshold, and the other below.
I got to pull out one of my Dremels and do some drilling and cutting, on my New-Old-Stock Wolfcraft "Quick-Jaw" Craft Table which was a lucky eBay deal given how rare they appear to be. The hassle avoided by skipping the C14 transferred somewhat to mounting the power outlet - the nut for the lower screw takes some patience and finger feel to get it started on the bolt. I did (and undid, and re-did) it a few times so I got the hang of it.
|
|
|
Once wired up, nothing went Poof! so all seemed good. The controller lit up, I could program it, the relay switched, but... no power. All my connections were good, though I used a too-heavy gauge wire to connect the Heat terminals to the outlet. The terminals seemed looser than the others. Everything else seemed to check out so Damn, I broke it. :( The eBay vendor I bought from had a Buy Another button and this one was $2 less than the first one, and came in about a week. Quick Salvation. |
Or so I thought. Controller #2 didn't work either. Hmmmm. This time I used lighter wire so the terminals wouldn't get stressed and none were. I'm doing something wrong. Back to the Instructables page and I see I should have returned to it earlier. The controller has a handy diagram of its terminals right on it and so I followed that - it looked pretty easy, just attach the right things to the right other things.
But no. That's not how it works and if I had looked through the Instructables page once more before wiring things up I'd have seen that the diagram on the controller is descriptive and not instructive. Googling STC-1000 made that apparent very quickly, and there are no end of diagrams from the home-brew crowd showing how to wire the thing up properly.
My wiring diagram - thin lines not used |
One handy feature a couple makers offered is an "always hot" plug, a split off the In line. I'm not sure how that would pack into the 4"x4"x4" box I'm using.
My simple application is not fused. Yours may need to be and several makers' are, especially for controlling a compressor-based Cool. |
|
So here's my diagram, to add to the many others. Even though I only use the Heat control I thought I'd add the Cool section too for anyone who wanders by. My key misunderstanding was that the power "bus" is supposed to be outside the device, provided by the users. The incoming Hot and Neutral lines must be shared externally among Power, Heat and Cool.
All wiring | |
|
Other makers use wire-nuts for the junctions, but I effected mine at the controller terminals with twisted wire into the sockets - make a tight twist, trim, and the sockets accept quite a large wire gauge. #1 to # 5 is a short run.
Controller wiring | |
|
Black and White are paired at the terminal. | |
Adding Cool requires a line from terminal #5 to #7. |
front | |
|
Sensor lead at top; power cord wound around base; controller instructions tucked in at the side.
I figure the blank area on the top will be handy for some kind of instructions since the ones with the controller are written in modern Chinglish and there are button sequences I won't remember. |
|
back | |
|
Sensor tip and Outlet plug. The power line enters the box through a tight hole, lower-left, with a zip-tie stopper. |
Right now it turns a lamp on or off depending on the temperature at the sensor. Whether I can make anything delicious now that I've been through this all awaits a further Clippings post.
Already I'm thinking of making another one with Hot and Cool, and the sensor lead coming out the side, with the first controller since it's probably just fine. There may be a follow-up.
)
)
)
)
)
)