Spring is here and time to get out the Terra Cotta smoker, but I wanted some sort of automatic control for the temperature. With this nifty little electronic monitor and controller you can make your dumb smoker a smart smoker and keep the temperature exactly where you want it. It will work with any plug-in electric smoker or BBQ. You cut up an extension cord, place this controller inline to the smoker power, set it and forget it! Here’s the shopping list:

Extension cord

Hammond 1591ESBK ABS Project Box Black

DN300A temperature controller

I chose the DN300A from Thermomart because it has a F range from -22 to 575. There are other similar controllers on the market that top out at 212 the but I wanted the extra range just in case I’m cooking hotter and faster. The only drawback are the leads to the sensor which you have to keep from melting, so keep them off the actual smoker. Some thermo-insulation should do to prevent accidents with that. I will try and find a thermo-resistant sensor later. The hardest part about the programming the unit is understanding to directions provided by someone that doesn’t speak native English. The unit uses a built-in relay to cycle power to the smoker based on the minimum and maximum values you enter. (Save an hour of frustration by setting it to H for Heat, from C for cool, first). Once setup you can apply power to your heating element based on the temperature of the probe!

Step 1: Cut a hole in the end of your project box for your controller. Remove the orange clips used to hold the unit in place and give it a test fit. 71x29mm does fine:



Cut another hole in the opposite end to run both ends of the extension cord through.



Here’s how the wiring goes together for the controller. I ran the wiring through the larger controller hole then slid them all back into place once connected. remove the little cover on the rear of the controller and make the connections.



Slide everything all back into place. Picture shows the rear controller cover back in place.



Secure the little sensor wires with the wire tie downs so you don’t accidentally pull them out. A couple loops tied with a zip tie should to it.

Slide the little orange clips back onto the controller body to hold the unit into the project box.



Button up the bottom of the controller box and get ready to program!



I placed my sensor bulb in the little gap in the ends of my smoker gasket. I’m leaving the sensor for the other thermometer to see how close/accurate they two are. Once I find a heat resistant one for the DN300 Ill replace them both.



So far the DN300A has a lot of good features:

You can calibrate the temperature 9 degrees each direction to make sure it’s where it needs to be.

It has too hot and too cold audible alarms.

Has a 0-999 minute timer.

Switch between C/F

High temperature limit of 572F

Adjustable hysteresis from 1-30 degrees.

Fast response from the sensor.

Total cost, about $50

I have been testing it out on the terra cotta and brinkman electric smoker all day and it’s cycling power perfectly to keep the temps perfect for smoking!

I used some spare nomex strip to make a protective sleeve for the sensor wires. Punch a hole in the middle of the strip, then remove the sticky side and fold it together to cover the first few inches of the wires. The brinkman I’m testing this on has a little gap around the top lid so it fits right in and doesn’t expose the wires to direct heat and keeps the leads from melting on the metal.



This SHOULD work perfectly for a charcoal smoker by powering a little fan to blow into the charcoal. I will make up and test a charcoal version next using a 12V wall wart to run a little computer case fan to add flow to the charcoal to raise their temperature too. It should have the same good results.