I am trying to build a small incubator for chicken eggs. It will be a small enclosed area no bigger than 4 cubic feet, probably closer to two, and some humidity. I would like a dc powered heater to bring it up to 100 degrees F. I want it to be DC so i can regulate it with a microcontroller, though any suggestions about learning to control AC power would be a help as well. In the meantime it would be nice if someone knew a good economical heater to use. Thanks for your help.

 

at that size, a light bulb could heat it. Light bulbs are cheap.

 

true, it coudl, but it would have to be 120 VAC, and to control it i would have to work with thrysistors and snubbers etc, with which im not very familiar, id like to be able to control the temp.

 

You can use low wattage incandescent rough service light bulbs. They're just heaters that also make a little light.

 

somethign like this?

http://www.amazon.com/Eiko-15816-RS-12V-Voltage-Light/dp/B000TZQUQ4

would that just run by splicing out an old lamp socket and pumping 12VDC through it? And also, that should produce enough heat?

 

Maybe you can use a water heater thermostat like this lady did.
http://bigredcouch.com/journal/?p=607

 

It boggles my mind that a person would say, I could use a microcontroller that can be implemented with hundreds of different programs and commands, but it's a challenge to use a triac because it might need 2 other parts. I guess that's because I'm old school.

I sincerely suggest you go with the pre-fab answers and don't try to computerize a light bulb.

 

lol, I understand what you mean, but its not the parts that are the problem, its the higher voltages and frequencies that I dont really understand, and would rather not mess with just yet. I'm a computer guy learning electronics, so the microcontroller isnt an issue, but im not super confident in my abilities to ensure that the voltages and electronics are safe. Like i said, any suggestions for a good way to learn and experiment with it that would be great, though, an easy solution in the meantime would be great too. I do appreciate your help though.

 

If I may betray where my parents came from, ignorant hicks have been doing this for decades with stuff like a water heater thermostsat and a light bulb. If what you really want is baby chicks, do it the easy way. If you want practice with a microcontroller, this site has a section just for that purpose. Whatever floats your boat, you can find it here.

ps, a water heater thermostat will control a 12 volt light bulb, too.

 

Yeah, and im realizing now that i am being kind of dumb about it since when i was thinking about controlling the temp, my mind was thinking of pwm dimming of the lightbulb when i realize from the link a previous poster sent it can be done by simply turning the light on and off as required, though i expect there would still be issues insulating the lower voltages from the higher, but i suppose thats only a matter of an optoisolator. A simple thermostat would work, though this is partly to practice with microcontrollers and electronics, but also to experiment with PID controllers, and trying to control the environment as automatically and precisely as possible, lol and yes, to also get chicks (not a statement often made wrt electronics it strikes me . I think ill try the low voltage lightbulbs, and if not ill break out the 110.

 

May your electronics knowledge get you all the chicks you could want.

 

Google for "solid state relay" they are safe and easy to use, the 2 mains connections are on one side and the other side has 2 safe opto-isolated connections that can be turned on with +5v DC from your PIC port pin.

 

May your electronics knowledge get you all the chicks you could want.

How's that workin' out for ya. #12 ??

 

I think you mean, "How's that working out for the OP?" He's the one hatching a scheme to get chicks with a microprocessor and a light bulb.

 

Hey guys, just wanted to say thanks for the help, it took me a little time and studying, and ordering of some parts, but I think i have the lightbulb working. It got me into controlling mains voltage, so i appreciate it. Now I have other issues to work out, but im getting there

 

Y'all r welcome to ask about any other thing that runs on electricity.
Good luck

 

Y'all r welcome to ask about any other thing that runs on electricity.
Good luck

Well as long as you do not put it in a car. or at least tell us you are going to use it in a car.
Anyway the project should be quite doable. At first you can start creating a on/off controller. Using a temprature sensor, and some internal ADC or comparator. Then perhaps move up a step and use PWM control. for tighter temprature control

 

Another possibility is a solid state relay for the 120VAC lamp side. AC control components are built in, and the input interfaces directly with a uC. Check MPJA http://www.mpja.com/3A-AC-SOLID-STATE-RELAY-480VAC/productinfo/18194%20RL/ or Jameco http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_175214_-1 has zero-crossing, for inexpensive SSR's

Ken

 

FWIW, I've just been repairing my food dehydrator and it contains a very simple circuit for controlling an AC powered heating element. The circuit is based on the CA3059 IC, which unfortunately is obsolete. Based on other things I've read, it was widely used. Not sure what replaced it.

Anyway, it's designed for direct (through a resistor) connection to the mains and controls a triac based on detecting zero-voltage crossings. It makes its own DC supply. A thermistor senses temp and turns the heater on or off. All of this is handled by the CA3059, so the PCB is quite simple. There's a thermal fuse that will trigger if the temp rises to about 20°F above normal range. (I think that would be a good addition to your incubator. You might want a cutout at just a few degrees above target, to avoid cooking your chicks.)

Thermostat and a lightbulb is the time-tested solution. Anything more is just showing off.

[EDIT] It appears that the Atmel T2117 is a replacement for the Motorola CA3059

 

The 12V Eiko bulb is a 100W bulb and should work great with PWM from the micro controller. Your thermal measurement should be where the eggs are and not another location. Not sure how you plan to monitor or regulate the humidity with the controller, but you will at least have a very consistent temperature. You'll have to power the bulb for 21 days, what were you planning on using for source power?