Introduction: Universal Controller for Sous Vide Cooking
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.
Again we've avoided soldering anything, which simplifies the construction considerably.
You can check out some recipes and more DIY sous vide advice at our blog. The details in this instructible are posted there as well.
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.
- PID Temperature controller JLD612 (Lightobject)
- Pt-100 RTD sensor (ebay or Lightobject)
- 25A Solid State Relay (Lightobject)
- SSR heat sink (Auber Instruments)
- Wire crimping tool and spade/ring/butt terminals (Amazon)
- 2 foot air conditioner extension cord
- 2 foot 12 gauge wire
- 1 foot double stranded 18 gauge wire
- 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.
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. Now, strip the three wires on both ends by carefully squeezing the scissors at different angles on the cord until the insulator is detached, less than ½ inch should be bare.
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 by a half inch. Strip the ends to expose the copper wire. Choose ring terminals 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 before--- we later crimp this end and attach it to the main 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.
Step 2: More Power
Splicing PID power cord and relay wires onto main power cordNow 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). 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. Then put the combined bundle in the other end of the butt connector, and crimp tightly.
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 socketNow 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).
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). 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.
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 3: 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.
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. 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 again.
Finally, we must connect the SSR to the heat sink. 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 4: PID Controller
Now connect the two ring terminals on the PID power cord to PID controller connectors 1 and 2. Again, to do this: unscrew the connector, insert the ring terminal, and putthe screw back in.
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.
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. 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 5: Play!
We use our universal controller to sous vide with a cooler! Here are the parts we use:
1000W bucket water heater (Amazon).It has been suggested that this heater is not safe for food use. For now, we recommend a cheap rice cooker.
- 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
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.