$70 DIY Sous Vide Universal Controller

We love how our $50 dollar sous vide is precise and stable over a long period of time.

However, we thought it’d be awesome to create a brain that could control anything based on the thermocouple output. Something that would work with a rice cooker, bucket heater, or even a smoker.  We could’ve gone out and bought a $160 Sous Vide Magic, but we built our own controller for $70! And now we’ll show you how to DIY.

Warning: do not embark on this if you are not comfortable with electronics, including high voltages. AC power direct from the wall goes through some connections, which can lead to personal injury or death.

ALWAYS use this device with a GFCI outlet or adapter.

NB, we have both a MAKE guide and an Instructible!

UPDATE: We now have a kit to build your own sous vide controller for $80!  It requires soldering, but we think it produces an elegant and convenient result.


Hardware supply:

  • 2 foot air conditioner extension cord
  • 2 foot 12 gauge wire
  • 2 feet double stranded 18 gauge wire
  • Scissors
  • Electrical tape
  • Duct tape

Step 1: Power

Like the $50 DIY immersion heater, the most complicated step here will be providing power to the PID controller and output.  We will use both ends of the air conditioner extension cord separately: the male end will provide power to the PID and heater, and the female end will be our output socket.

Fig 1. Wiring diagram

Main power cord and output socket: Use scissors to cut six inches of extension cord from the female end (output socket). You should be left with 18 inches of wire on the male end (the main power cord).  For each end, carefully cut along the cord to separate the three wires: the two power lines and the ground (usually smaller, Fig 3). Now, strip the three wires on both ends by carefully squeezing the scissors at different angles on the cord until the insulator is detached (Fig 2), less than ½ inch should be bare (Fig 3).

Fig 2. Strip the thick insulator by slowly wedging the scissors around the wire.

Fig 3. The main power cord has two power wires and a ground.

PID power cord: In order to pull out power for the PID controller we will cut our double-stranded wire in half ( the other half will be used for the relay control cord). Now split the wire in half (Fig 4) by a half inch. Strip the ends to expose the copper wire (Fig 4-5).  Choose ring terminals (Fig 6) that will fit on the screws on the back of the PID controller then use the crimper to attach the ring terminals to the ends of the wire. Separate and strip the wires on the other end of the cord just as in Fig 4 and 5— we later crimp this end and attach it to the main power cord.

Fig 4. Split the cord into two wires.

Fig 5. Strip the ends with the wire stripper.

Fig 6. Ring terminals on the PID power cord.

Power relay wires: Cut the 12 gauge wire into three wires of equal length. Strip both ends of each wire so ½ inch of copper is exposed.

Splicing PID power cord and relay wires onto main power cord

Now we will attach two power relay wires and the PID power cord to the main power cord (the male end). Using the crimping tool, attach one end of a butt connector to a strand of the main power cord (not the ground; Fig 7).  Tug at the connector to make sure it will not come loose.  Combine one power relay wire and one strand of the PID power cord by flattening the copper fibers with your fingers and twisting them into each other (Fig 8-9).  Then put the combined bundle in the other end of the butt connector, and crimp tightly (Fig 10).

Fig 7. Main power cord with butt connector

Fig 8. Flatten the copper strands of both wires.

Fig 9. Combine wires by twisting together.


Fig 10. Each power wire in the main power cord now connects to one PID power wire and one power relay wire.

Again, make sure that the connection will not come loose by tugging on the wires. Then combine the other wire of the main power cord with the other strand of the PID power cord, and another power relay wire through the method used above.  If any wire comes loose, you may need to cut off the butt connector from the main power cord, strip the wire again and attach another connector.

Connecting output socket

Now connect the ground from the main power cord to the ground on the output socket using a butt connector.  Attach the third power relay wire to one of the two power wires of the output socket using a butt connector.  Then connect the remaining power wire of the output socket to the corresponding relay wire spliced off of the main power cord (to determine which is the corresponding wire, you can plug the main power cord into the output socket).

Fig 11. Connections between main power cord and output socket.

At this point, the only remaining free ends should be the two ring electrodes on the PID power cord and two power relay wires (one on the main power cord and one on the output socket; Fig 12).  Choose two ring terminals that will fit on the solid state relay contacts. Then connect those ring terminals to the free ends of the power relay wires.  Be extra careful that these are crimped well.

Fig 12. All power connections.

Finally, pull on all your connections.  If anything comes free, reconnect with another terminal, and try to squeeze harder when crimping.  Safety is more important than saving time.

Step 2: Solid State Relay

Relay control cord: We are almost done stripping and crimping, but we first need to make a wire to allow the PID controller to activate the relay. Take the remaining length of double stranded cord, pull apart the wires at the ends, and strip them so that ¼ to ½ inch of copper is bare.  Choose spade electrodes that fit on the connectors at the back of the PID controller and attach four of those spade electrodes to the four wire ends (Fig 13).

Fig 13. Relay control wire with spade terminal attached.

Fig 14. Solid state relay (SSR) with all connections.

From here on everything is easy peasy, screwdriver only work.  Connect one end of the relay control cord to the SSR terminals 3 and 4 by screwing down the spade connectors (Fig 14).  Connect the two ring terminals attached to power relay wires to SSR terminals 1 and 2 by removing the screws on the terminals, insert the ring terminals and tighten the screws firmly (Fig 14).

Fig 15. Apply thermal paste to the top of the heatsink.

Fig 16. Attach the SSR on top of the heatsink.

Finally, we must connect the SSR to the heat sink (Fig 15-16). The SSR is rated to 25A only if connected to a heatsink–otherwise the rating drops to around 7A, and decreases further at higher temperatures.

Step 3: PID controller

Now connect the two ring terminals on the PID power cord to PID controller connectors 1 and 2 (Fig 17).  Again, to do this: unscrew the connector, insert the ring terminal, and putthe screw back in.

Fig 17. Back of PID controller.

Attach the free end of the SSR control cord to PID terminals 6 and 7, loosen the screws, insert the spade terminal, and tighten the screw again.  The wire from SSR terminal 3 should go to PID terminal 6, and the wire from SSR terminal 4 to PID terminal 7 (Fig 17-18).

Finally, attach the Pt100 wires to PID terminals 8, 9, and 10.  If the Pt-100 has three wires, connect the red, blue, and yellow to terminals 8, 9, and 10 respectively (Note Fig 17 is incorrect).  If your Pt100 has only two wires, connect the red and blue to 8 and 9, and then connect 9 and 10 together with a short wire.

One thing we noticed is that the Pt100 probe gives some wonky results if the back end gets even a little wet, we wrapped it up in duct tape and electrical tape to avert this.  Perhaps a better idea is to put the entire probe inside a finger of a latex glove, as we did in the DIY cheese vat.

You should also update your PID settings to save time heating up your water bath.

Step 4: Play!

The simple version setup can be seen in Fig 18. Plug in whatever heating element (immersion heater, crock pot, etc) to the output socket, and put the Pt100 probe in the water bath (the environment being heated).  Plug in the main power cord, and voila!  The PID controller will start to adjust the heat to reach the Set Value (SV) temperature.  Adjust the SV by using the up and down arrows on the PID controller.

Fig 18. The PID and SSR on top of the cooler.

We use our universal controller to sous vide with a cooler!  Here are the parts we use:

  • 1000W bucket water heater (Amazon). 
  • 16-quart (or larger) cooler (Local store or Amazon)
  • Ziploc vacuum (sous vide) pump and bags (Amazon)
  • Elite A800 aquarium air pump (Amazon)
  • Aquarium air tubing
  • 3-prong extension cord or surge protector

Note: The bucket heater may leech small amounts of lead into the water, but we think your food will be safe in a plastic bag (thanks to commenter salvarsan).  Be careful when disposing of the water.

On top: PID controller, SSR with heatsink, and air pump. Going into the cooler: air tube, heater, and temperature probe.

The setup is very simple. We tied the end of the air tubing in a knot, and threaded it through the bottom holes in the bucket heater.  Then, we taped the air pump to the top of the cooler, and plugged it into the surge protector.

We placed the bucket heater inside the cooler, and plugged it into the output socket.  The controller’s thermocouple is left to dangle in the water.  The controller is plugged into the GFCI adapter, which goes into surge protector.

That’s it! We fill the cooler with water, flip the switch, and enjoy some tasty, juicy sous vide cooking! We hope you’ll have as much fun with it as we’re having.

Edit 3/23/2011: Added GFCI and clarified a little, thanks tward

Edit 4/2/2011: Removed bucket heater for food safety reasons.

Edit 4/4/2011: Fig 17 displays incorrect Pt100 lead order, thanks tward

Edit 4/6/2011: Bucket heater comment modified, thanks to salvarsan!

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52 Responses to “$70 DIY Sous Vide Universal Controller”

  1. John
    February 24, 2011 at 12:14 pm #

    Hello Abe,
    I just found your site yesterday and am finding a lot of interesting information. Thank you!!
    Although the Sous Vide information is intriguing, at this point I am particularly interested in the cheese vat applications. I read about the DIY $100 cheese vat but now have found this page for the universal controller. I like the idea of the flexibility this option provides. Is there any reason, why this could not be used with a roaster by simply plugging the roaster into this unit rather than installing the equipment directly as you have shown in the cheese vat/sous vide unit?

  2. February 24, 2011 at 4:02 pm #

    Hi John,
    Yes, I would recommend using this type of device rather than the other for flexibility. The advantage to the other is a somewhat cleaner device, if you can attach everything to the roaster. Although you could certainly make an enclosure for the electronics here as well. Good luck with the project! Let me know how it goes.

    • Shane
      November 19, 2011 at 11:33 am #


      Enjoy your articles.

      Question: JLD612 output light blinks. Thoughts on how to correct?


  3. tward
    March 22, 2011 at 8:59 pm #

    This looks awesome. I’ve got a few questions / comments (and I’ll bet I’ll have more once I get started!)

    Before I start, I want to thank you for sharing all of this.

    1) Do you have anything against soldering and using wire nuts instead of the method above with crimping + butt connectors? (I’m wondering if you think soldering would technically be a more ‘solid’ construction, but favored the above due to simplicity / fewer tools and technical skills.)

    2) If one were to “containerize” this set up (the controller along with the relay and heat sink) it seems like it would be smart to cut some vents near the heat sink rather than fully sealing the container?

    3) Some SeattleFoodGeek commentary discussed the use of GFCI. It seems the main power cord should be plugged into a wall socket that has GFCI or it should be plugged into a a power strip with GFCI that is in turn plugged into a wall socket without GFCI. Thoughts?

    3a) Just making sure I understand how you plugged in everything for the sous vide cooler set up described at the end. When it says “The controller is plugged into the surge protector”, the “controller” is the “main power cord” (as described in the paragraph immediately below “Step 4: Play!”). The pump is plugged into that same surge protector and the surge protector is plugged into the wall socket. Similarly for the bucket heater it says “plugged it into the controller” which I take to be the “output socket” (as described in the paragraph immediately below “Step 4: Play!”).

    4) I’m wondering what we see in at the bottom center of the second to last photo (the larger cooler photo showing the front of the cooler). It looks like a three pronged socket, but given the description I can’t understand why it would be leading to the cooler opening.

    Thanks again for all the work and the help.

    • March 23, 2011 at 12:08 am #


      Thanks for your feedback! I’ll respond directly to your questions first:

      1) Yes, solder is definitely better for the wire-wire connections. I would only recommend butt connectors if you do not have soldering tools handy.
      2) This is correct, the container should not be completely sealed. This is why I am a bit wary of Scott of SeattleFoodGeek adding a SSR directly. If you cut holes and use a heatsink I’d say you’re golden.
      3) Yes, I will add a warning to use with a GFCI socket only. It is much, much safer with that installed.
      3a) You have it correct, I realize I deviated from the more specific language from earlier. I’ll try to improve this as well.
      4) This is the top of the bucket heater, it is a bit rectangular with some warning stickers on it. The heater is at an angle to fit into the cooler.

      Good luck with the construction. Let me know how it turns out!


      • tward
        March 23, 2011 at 12:54 pm #

        Thanks so much for your replies. They help me gain confidence for sure!

  4. tward
    March 25, 2011 at 8:55 pm #

    A few more quick questions and thoughts:

    A) Any idea what the unused terminals of the controller are for / could be used for? Are they alarms? Any idea what kinds of alarms can be set and what they could be used for?

    B) It seems like as soon as the controller is powered on, it begins controlling, so you’ve got to have everything in place thermocouple, heater, (pump)] before powering. In other words there’s no “start program” or “go” on the controller.

    C) Any idea how a water level sensor could be worked into the circuit? It would be great to install a water level sensor onto the heating element that would interlock so that the heater only gets power if the water level is detected. (Of course for this universal controller there would need to be a way to override that, since it is not helpful when using something like a crockpot as the “heating element”.)

    • April 2, 2011 at 12:55 pm #

      The other terminals are switches for alarms–you can find the manual at lightobject. They are a bit complicated to change, and since I change temperatures and cycle on and off pretty frequently, they haven’t been useful to me.

      It is correct that there is no start button, so you need to make sure everything is in place before plugging it in.

      Unfortunately everything here is kind of a mess. We are working on a kit to replace everything and fit it in a box–should be a bit safer and more hacker friendly. I expect we will have a website up with info in a week or so, so watch out!

  5. ajfesq
    March 26, 2011 at 12:21 pm #

    When you say “the back end” of the PT100, where do you mean? Would shrink wrap tubing or “liquid electrical tape” work to make the probe fully submersible?

    • March 26, 2011 at 9:20 pm #

      Shrink wrap is generally not designed for full immersion, but liquid electrical tape sounds like it would work. We keep the probe part of the Pt100 assembly fully underwater, but keep the connection between the bolt and wire above water. That part we have completely covered with duct tape, which has been ok so far. Watch out that a lot of tapes or glues will melt at sous vide temperatures, making full immersion more difficult.

  6. tward
    April 5, 2011 at 1:12 am #

    I think a correction to the thermocouple wiring information is required.

    The instructions read “If the Pt-100 has three wires, connect the red, blue, and yellow to terminals 8, 9, and 10 respectively (Fig 17).” However, Fig 17 photo shows yellow, red, and blue to terminals 8, 9, and 10 respectively.

    • tward
      April 5, 2011 at 11:51 am #

      FYI, I’d followed your link above to download the manual from http://www.lightobject.info/viewtopic.php?f=13&t=3

      That page states “For PT-100 thermocuple, the Red tag need to tap to the #8”. So that seems to settle that the photo in Fig 17 is incorrect for a PT-100.

      Note also that seattlefoodgeek.com (http://seattlefoodgeek.com/2010/02/diy-sous-vide-heating-immersion-circulator-for-about-75/ – see “Wiring diagram for JLD612 PID Controller with SSR” *) shows the order as red, yellow, blue for #8, #9, and #10, respectively. (This is supported by a comment from “Julian” who wrote in the comments “For those with the JLD612, you don’t actually need contact 11, your pt100 connects to 8, 9, and 10 with red, yellow, and blue respectively.”)

      * Note that “Wiring Diagram for CD101 PID Controller with physical relay” shows red, blue, yellow.

      It appears that both the PT-100 wiring instructions AND the photo in Fig 17 are incorrect. That said, the blue and yellow may be able to trade places on #9 and #10 based on what I know about the PT-100.

    • April 5, 2011 at 5:08 pm #

      Good catch on Fig. 17, that is clearly wrong. I think red, blue, yellow is correct, Edinburgh Foody found that to be slightly more accurate. I am actually surprised there is a difference because the leads are so short.

  7. tward
    April 5, 2011 at 4:04 pm #

    Re: “Edit 4/2/2011: Removed bucket heater for food safety reasons.”
    That seems to be out of an abundance of caution. The food in sous vides is contained within a sealed bag and is thus physically isolated from the heater and the water in contact with the heater. It seems that any food safety issue would only come into play if one were using the device to heat liquid into which food was directly placed (e.g. oil poaching fish).

  8. Wali
    April 5, 2011 at 4:25 pm #

    What’s the problem with the bucket heater? Electric water heat is electric water heat no matter what the hot device it comes from and it never comes in contact with the food anyway (does it?)

    BTW: yours is an excellent tut and this is not a criticism. I’m just a bit confused.

  9. April 5, 2011 at 5:30 pm #

    Regarding the bucket heater: I am not a chemist, but I am not sure that we can expect a plastic membrane that keeps out water to also keep out aqueous metal ions. The transport is fundamentally different, as water is a polar molecule that will not break its bonds, while the metal ions could potentially diffuse through the plastic by forming weak bonds with plastic molecules.

    I am erring on the side of caution, as there is no safe amount of lead to consume. There is the Electra Water Heater on Amazon for $60 and McMaster sells an identical one for $70 (product id 3583K92). It seems like a small price for safety.

    We are working on importing some heaters from China that will be much less expensive and food safe. We will certainly let you know when those are available.

    • salvarsan
      April 6, 2011 at 11:22 am #

      Metal ions bind to plastic bags no more than water ions unless the plastic is an ion exchange resin (unlikely & expensive). At issue is that if lead leeches from the bucket heater, then you must handle contaminated water.

      • April 6, 2011 at 11:59 am #

        Great! Thanks for the comment!

  10. tward
    April 7, 2011 at 12:13 am #

    Well I built my first version using the above instructions and it works!

    I’ll be swapping out the PID power cord and the relay control cord for longer widths though. Those two are made from half each of “1 foot double stranded 18 gauge wire”. At six inches they aren’t long enough. (The Fig 18 photo looks like it’s got longer than six inches for the relay control cord.) I’m thinking a full foot each will be enough for flexible positioning of the PID unit and the relay unit without introducing too much extra wire.

    I’m also thinking about using a barrier strip to connect the wires instead of butt connectors, but I’ll wait to make that change until I figure out a viable housing for the units.

    • April 7, 2011 at 3:31 pm #

      Awesome! You are right, I must have used two feet, it is certainly more than 6″.

      If you find a barrier strip that is useful and completely covered, let me know, I am thinking that would be better as well. I was anti-screws to begin with (they put more pressure on the wire than a crimped terminal), but I have found that they can be a bit more reliable.

  11. tward
    April 7, 2011 at 5:51 pm #

    Though the Fotek SSR I use doesn’t have an available datasheet, I found an excellent datasheet with a wealth of information at Opto22. (Download from )

    Particularly interesting to this build is the discussion of SSR failure. The Q&A section states that if an SSR fails, it’s usually from one of three reasons. The first is running overcapacity (too much current for too long) – the datasheet has great curves for showing the impact of ambient temperature and heat sink on amp derating. The second relates to inductive loads (not applicable to our heaters). The third is most interesting to this build, since we only use crimping:

    “SSR improperly installed. The SSR was not mounted to a large enough heat sink, or no thermal compound was used, causing the relay to overheat. Also, insufficient tightening of the load terminals can cause arcing and ohmic heating of the relay. Opto 22 recommends 18 inch-pounds of torque on the load screw terminals. Similar failures have also been attributed to the use of crimp-on terminal lugs or spades; make sure such terminals are tightly crimped, and even drip some solder into the joint to ensure good electrical contact and protection from corrosion.””

  12. tward
    April 7, 2011 at 5:54 pm #

    Woops… posted before including the link…
    Download from Opto22: http://www.opto22.com/site/documents/doc_drilldown.aspx?aid=1677

    • April 7, 2011 at 7:32 pm #

      This is a great datasheet. I am fairly confident that ring terminals can carry this current without additional solder–I have used them to carry up to 100 A before. But it might be worth mentioning the importance of having them tightly attached to the SSR.

  13. Chris
    April 12, 2011 at 10:39 pm #

    Thanks for the great post, just hooked everything up to a roaster oven and it works great!
    The only problem I have is that the other outlets are controlled by the PID also and therefore the power flickers on and off.
    This poses a problem when hooking up the aquarium pump – anyone have the same problems/a solution?

    • April 12, 2011 at 11:31 pm #

      I’m so glad the article was helpful!

      I plug a surge protector into the wall and then the AC cord for the PID controller (“main power cable”) into the surge protector. I’m not sure how you hooked it up exactly–if you have multiple outlets where it says “output socket,” those will all be pid controlled. But the other surge protector sockets should be always on.

      Good luck!

      • Chris
        April 17, 2011 at 10:15 pm #

        Oh, I see. I’m trying to hook a standard household two outlet receptacle up and have one PID controlled and one an always on non-controlled outlet in lieu of using a surge protector. Still no luck. Sorry for the confusing wording.

        • Stephen
          May 23, 2011 at 11:32 am #

          I using this same concept. I made an enclosure to house the electronics and made a heavy duty electrical outlet the connection points for the water bath electrics. The first outlet is connected to the PID controller for the heaters and the second is for the continuous power, i.e. the water pump. I disconnected the bridge on the outlet to prevent the controller controlling both outlets. Once I get this up ad running I plan to swap the water heaters for an electric hot plate and the water pump for a small fan to make a smoker.

          I am having some troubles though. After the first few setups not everything was working together nicely. First the water pump was not working with its outlet but the PID controller worked great. I’ve gotten the water pump working but now the PID controller is showing EEEE on the top line. I’m not sure what I am doing wrong. I’ve used your parameters for setting up the JLD612 and have had it work. Any ideas why the controller is just showng EEEE?

          BTW, Thank you for having this in Make magazine. I saw this setup and knew I had to do it. I can’t wait to make this thing fully operational. During my “testing” I wanted to see how well it worked and I figured, “why not cook an egg?” So I did and it was amazing. My sister-in-law raises chickens and we get our eggs from her. Amazing. I can’ t wait to try out the other recipes that are out there. Again, Thank you.

          • May 23, 2011 at 6:14 pm #

            EEEE usually shows if you don’t have the right themocouple input selected. First make sure the thermocouple is attached properly–you might have switched the wires going into the PID controller.

            If that doesn’t work, hit SET and enter “0089”. Then press SET when “Inty” is blinking. Then scroll using up and down arrows to Pt10.0 if you are using a Pt100. Mine was on that by default, but it is possible yours is not or it changed itself.

            Eggs are pretty amazing cooked sous vide. Try deep frying the yolk! I hope your sous vide adventures are delicious and everything works out!

  14. Stephen
    May 26, 2011 at 6:52 am #

    Thanks for the help. I think I found out part of the problem: the SSR is not working. During my first test I noticed the SSR light turning on and off whenever the controller would need to heat the water up. I got a new relay and will be hooking it up.

    I’ve been reading through your awesome website and have just been drooling over the recipes. My wife was at work when I made the eggs, so just me and my daughter got to enjoy them.

    I can’t decide if the first meal I’ll make for her will be Sous Vide Eggs Benedict or Sous Vide Salmon.

    BTW, I saw your post about frying the egg yolks. Once I read that, it was the point at which I had no other choice but to make this amazing machine. Thanks for all your work, experimentation, delicious recipes, motivation, and support with this awesome project.

  15. David
    June 29, 2011 at 6:21 pm #

    Thank you for this guide! I used this guide along w/ Scott’s and just finished making my own universal controller! If anyone is interested I used the smaller JLD614 (http://www.lightobject.com/Search.aspx?k=jld614) instead of the JLD612.

    I was curious if you/anyone knows if a tank/pond heater would work? I was looking at something like these:

    K&H Manufacturing Perfect Climate Deluxe Pond Heater: http://www.amazon.com/Manufacturing-Perfect-Climate-Deluxe-1500-Watt/dp/B001KC2A0U/ref=sr_1_2?s=home-garden&ie=UTF8&qid=1309385037&sr=1-2

    API 15N 1500-Watt Sinking Tank Heater with Guard: http://www.amazon.com/gp/product/B000BD8JAE/ref=olp_product_details?ie=UTF8&me=&seller=

    If those wouldn’t work, any suggestions on high wattage heating elements(~1200-1800 watt), preferably with some form of shield/guard?

  16. crom
    September 19, 2011 at 9:58 pm #

    I built this and it works great, except for one little quirk. Whenever I touch the cord on the thermocouple (without moving the thermocouple at all), the numbers on the PID start going all wonky. Any ideas on why this might be happening?

    • September 19, 2011 at 11:59 pm #

      I think we had a similar problem, but I can’t remember the exact situation. It might be that the lead to the thermocouple is wet, or the leads are not well attached. Try drying it out in some rice and then submerging it in the finger of a latex glove, or using sugru to waterproof the connection.

      If this doesn’t work out for you, try getting a multimeter and testing the resistance between the leads. This will help you determine if you have a defective Pt-100 versus a wonky PID controller.

      • crom
        September 25, 2011 at 10:50 am #

        Thanks for the response. I don’t think its a problem with the thermocouple being wet because this was happening before I put it in water (and when I did put it in water, I did so inside a latex glove). I don’t really know anything about electronics or how to use a multimeter so I may just order a new PT100 and hope that solves the problem.

        By the way, sugru looks amazing. I am definitely buying some.

    • crom
      September 29, 2011 at 5:47 pm #

      Update: I got a new thermocouple (the waterproof version this time) and now everything works fine. I hope Lightobject refunds me for the faulty thermocouple.

  17. Kolton
    October 14, 2011 at 4:44 pm #

    I noticed you used a RTD (measures a change in resistance), do you know if your controller would work with a thermocouple (measures voltage difference)?

    • October 24, 2011 at 10:54 pm #

      The JLD-612 works with any type of thermocouple, and it generally holds the temperature to within half a degree. It is constantly (every 3 seconds) turning the heater on and off in order to maintain the temperature constant, rather than sawing up and down between two cutoffs like an oven or cheap appliance.

  18. Kolton
    October 14, 2011 at 5:00 pm #

    Also, does the PID get set to a temperature and hold it plus or minus a degree? Or is there a range like 230F it opens the circuit and 220F it closes the circuit?

  19. Sparky
    November 4, 2011 at 12:30 am #

    Is there any downside to using a much higher SSR like 60A? Would this minimize the need for a heatsink?

    • November 5, 2011 at 3:11 pm #

      There is no downside to a higher rated SSR, but it would not reduce the need for the heatsink based on the models I have seen. The silicon junction will generally require a fixed voltage drop, which will create the same heat at the same current no matter how large the junction area is.

  20. Andrew
    February 11, 2012 at 2:19 am #

    Hi, Thank you for this great article.
    I live abroad and the voltage here is 240V, can I use the same parts you listed to build the device and plug it in a 240V outlet?



    • February 11, 2012 at 4:50 pm #

      Yep, everything here works up to 240 VAC. Glad you liked the article, good luck with your hacking!

  21. Josh
    April 4, 2012 at 7:48 pm #


    Thanks for taking the time to go over this. Unfortunately I think that your instructions are somewhat confusing as to what wire you are connecting to where. I think you should make a video so people can keep track of which wires you are using for which connection, this would be immensely helpful especially for showing the twisting and connection aspects. The diagrams just show the connection of the wires but not which wire is which. Keep up the good work!

  22. Theo
    May 14, 2012 at 9:28 am #

    Hi, I’m a student in the UK and after trying a sues vide egg in a restaurant I talked about it so much that me and my housemate are going to attempt this project.

    However its quite expensive to have the PID controller you suggest shipped to the UK ($41 dollars, or if I feel like a quick trip overseas I can pay $4 to pick it up!) and appears only to be available via Lightobject. Is there another you have used that you could suggest?

    I’m nervous about selecting one as I don’t want to loose accuracy!

    Thanks in advance,


  23. Evan
    August 24, 2012 at 12:33 pm #

    Hi, I’m wondering if rather than using crimped connectors I can just strip the end of the wire, coil it in a U shape, and put that coil of exposed wire under the screw and plate (so the little plate beneath the screw is above the wire and the screw pokes through the center of the U)?

    • Abe
      February 12, 2013 at 11:30 am #

      This is ok in a pinch, but the crimped connectors will be much better if you end up connecting and disconnecting the wire a few times.

  24. adip
    February 11, 2013 at 5:59 pm #

    Hi, im a student in Indonesia, My SSR does not function. What may
    have happened? My SSR Same like your article..
    thanks before…

    • Abe
      February 12, 2013 at 11:32 am #

      You may be switching the polarity on the DC side. Try attaching the AC side to a lamp first to make sure it’s the SSR that is not working. If not, try switching the DC side wires. Otherwise you might have received an SSR that is not functional. Good luck!

  25. Joe
    February 27, 2013 at 3:28 pm #

    Just a couple of comments:

    Solder versus crimped. Talk to any mechanic (especially marine) and they will tell you 90% of the problem wire connections they find are soldered. Look at the electrical system in your car, crimped. Crimped is easier and a far more reliable attachment.

    If you are having problems, plug your unit into a non-GFI outlet. SSR’s can drive GFI’s nuts with their constant and lightening fast on/off states.


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    […] built my first sous-vide cooker using a combination of Scott Heimendinger’s and Q and Abe’s DIY instructions. Now Q and Abe is raising capital for the Nomiku, a commercial product aimed at […]

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