Earlier I mentioned about a method that would help us test the functionality of our SSR. By connecting the SSR to a very simple circuit, with a battery, a light bulb and an AC source.
The DC control voltage will be the battery with the positive “+” sign connected to terminal 3 and the negative “-” sign connected to terminal 4 of the solid state relay. On the load side (terminal 1 and 2), we will have the light bulb (load) with one terminal connected to one side of the AC source and the other terminal connected to terminal 2 of the SSR. The other wire of the AC source will be connected to terminal 1 of the relay to close the circuit.
If the SSR works, then when the DC circuit is closed the light bulb will be turned on, else it’ll be turned off. The test was a success and the result looks as below:
After knowing that the SSR works correctly, we moved on to test the RoastLogger software using this same circuit, but this time instead of the 5V-battery, we hooked up the SSR with our Arduino/TC4 microcontroller. The system now looks as below:
Terminal 3 and 4 of the SSR are connected to terminal OT1 of the microcontroller. This terminal OT1 as specified in the code is the 16-bit timer for SSR output that eventually we will have on the heating elements on the toaster oven. After the system is connected, we ran the RoastLogger sketch and opened the RoastLogger software interface.
The manual controller from the RoastLogger program allows us to change the power of the components connected to the microcontroller. At 0% the light bulb doesn’t light up at all. At 50% it keeps turning on and off respectively, each for roughly 1 second. At 100%, the light bulb is always turned on.
O% Power
50% Power
100% Power
Therefore, without even looking at the code, we can deduced that the RoastLogger software somehow manipulates the power the frequency signal to the components. At 100%, the frequency is set up to be very high so that we cannot see the light fluctuating with our eyes. At 50%, the frequency is fixed so that it’s turned on and off for exactly 1 second each. At 0% then it’s probably just connected to the ground and therefore is not turned on.
