Homemade Incubator Thermostat - Video Link

[tracecom]

I have never hatched a single egg and never owned a live chicken, but I plan to change that soon. I have read extensively here and appreciate the expertise of so many of you.

The topic of thermostats comes up here so often, I couldn't resist trying to design a controller suitable for an incubator. The following video shows my prototype in action. The styrofoam cooler is a shipping container for frozen meat that I bought at Goodwill. As you can see, I am using a light bulb for the heat source, but I have also designed a heating element that uses nichrome wire. (My first prototype of the element had too much thermal mass, which I have corrected in the design, but have not yet built.)

The hysteresis on my controller is adjustable, and I have it set for minimal deviation from the set point.

Sorry for the poor video quality. Let me know what you think of the controller.

P.S. That's my cat, Jack, meowing at 55 seconds into the video. He wants baby chicks too.

 

[pwd]

looks great please show us how you did it.

 

[rebelcowboysnb]

Now that is sensitive... With it cycling that fast you wont get much life out of that light.

 

[tracecom]

Quote:
There seem to be differing opinions on whether turning an incandescent light on and off shortens its life. Of course whenever a bulb "shoots" as we turn it on, that tends to make us believe that turning it on was what caused the filament to fail, but I'm not so sure. Many experts believe that it is heat which weakens the filament and causes it to fail; if that is true, then my bulb may actually last longer since it does not get as hot as it would if it stayed on longer. In addition, my controller turns the bulb on electronically which could be easier on it than a mechanical switch or a relay. Maybe I'll put a new bulb in it and run a life test. Anyway, I plan to use a nichrome heating element once I get it built.

Thanks for your comment.

 

[rebelcowboysnb]

Its the thermal change at the element that shortens its life. It heats the instant it comes on an cools very fast. The time it is own only effects how hot the glass is not the filament. A bulb has so many cycles in it. The speed of them don't seem to affect much. But, what does it matter... You are not planning to use a bulb.

 

[monster1]

thats cool! where did you buy it? i looked on ebay and did a google search and came up with nothing.

thanks

 

[Whitehouse Quail]

Welcome to BYC!

Anyway, that's an awesome looking controller. How did you create it?

 

[tracecom]

Quote:
Quote:
It's homemade and consists of three sections: the actual thermostat (a comparator circuit), a solid state switch for the 117vac, and a power supply to run the whole unit. It has LED's on the front to indicate power-on (green) and heat (red), and two low voltage outlets (one for a fan - unswitched), and one for a light (switched). It's still in the testing phase and I have in mind another feature or two.

What else does it need?

 

[aprophet]

Quote:
Quote:
It's homemade and consists of three sections: the actual thermostat (a comparator circuit), a solid state switch for the 117vac, and a power supply to run the whole unit. It has LED's on the front to indicate power-on (green) and heat (red), and two low voltage outlets (one for a fan - unswitched), and one for a light (switched). It's still in the testing phase and I have in mind another feature or two.

What else does it need?

Depending on what kind of bator someone has built or is using ,a potentiometer to ajust the hysteresis/differential would be kina nice to fine tune your heat source

 

[tracecom]

Quote:
My controller has adjustable hysteresis, but the adjustment is on the inside of the controller box. Putting the control on the outside is possible. Thanks.