Yep, it's just a toy. And the sensor should be placed in one end of the weasel/wiggler/weiner thing and pushed toward its center. The circulated air bator temp in it should be about 99.5-100 degrees.
Just to make sure I have this right, before I head to the store...
Get a fan to keep the temp in the cooler even...
Get a thermostat and light to maintain ambient air temp at 99.5 to 100.
Get a thermometer with sensor to track the in-wiggler temp and the ambient humidity.
The rest of the structure I understand.
My next question is why put holes in the cooler and plug them with corks (i am looking at MissPrissy's instructions). If they should be removed, how often and for how long?
Your sensor won't track humidity, only temp, unless you get a much more expensive unit than most people buy. The probe is actually made to sit outside a window to measure outside temps, but we are all using it for the inside bator temp. The humidity reading on most units is only read by the entire unit so if you want that humidity, you'd have to place the whole unit inside. I found a small thermo/hygro with a suction cup made to stick outside a window and it reads both so I can put the entire thing in the bator and not take up room.
You will always need airflow in a bator, moreso as hatch time is near and alot during the hatch. I don't have a styrofoam homemade bator, mine is wood. We drilled holes all around the sides just above the bottom for air to be drawn in and we have those holes MissPrissy mentioned, which, as long as I can keep the humidity up, are left open. Here's a pic of our homemade bator:
I built my incubator last night. Looks like it will work well. I really wanted a thermometer that would show both temps and humidity so I ordered one off the internet for 20 bucks. When I get it, I will take pictures of my setup.
Oh, I also resolved the egg turning issue. From the time the eggs go in to the time the chicks come out, the lid will never have to be opened.