Installing the Solid State Relay

I conducted a simple test today by hooking up the Solid State Relay (SSR) to the toaster oven and an Arduino's power supply.

The hot wire was already connected to both heating elements so I just connected the neutral side of the heaters to terminal 1 of the SSR using a connector I bought from RadioShack. Terminal 2 is connected to neutral in the power outlet. Terminal 3 and 4 are simply connected to 5V and GND on my Arduino. Having 5V across terminals 3 and 4 turns on the relay, creating a return path for current to pass through the heating elements. You can see that the toaster was successfully turned on.

Now, all I have to do is install the thermocouple and digitally control the temperature using the Arduino.

Taking Apart the Toaster Oven

Today I spent some time taking apart the toaster oven that'll be modified into a reflow oven. Not surprisingly, it was mostly empty. The wires seen here are temperature resistant, so I will be hanging onto these, and unlike most others I plan to keep the knobs in place for aesthetics. Now I need to figure out where to mount the thermocouple, which by the way I had to remove the heat shrink from because it will be heated beyond its 250C rating. I also now need to order the Solid State Relay I've been putting off buying.

Making a Reflow Oven

I've started working on a DIY reflow oven based on this instructable.

Instead of working on it my usual way from scratch I decided to do it the easiest and fastest way using an arduino and a breakout board from adafruit linked here.

Today I got my breakout board and thermocouple in the mail so I put it together and tested it with the example code provided on the website. It turns out that as people have noticed the thermocouples have incorrectly colored wires. This was easily fixed by reversing the wires.

I broke down the project into the following steps, of which I am now moving on to step 2. However, before moving on to the next step I will need to figure out if the heat shrink around the sensor can handle high temperatures. When I tested it over a lighter it was smoking a bit and most pictures don't show a heat shrink tube around it.

1. Setup and test the thermocouple
2. Install thermocouple in toaster oven and monitor its temperature
3. Order then install a solid state relay to control the temperature