DIY Incubator Thermostat

[Old McRonald]

I have a homemade incubator with a hot water heater thermostat that I added an auto turner early into a batch of duck eggs, in fairness I did raise the eggs up a few inches to better install the turner . Didn't touch the thermostat, I did move the fan a little to make room and left for work. Came home 10 hours later to a temperature spike of 111F, opened the lid and adjusted the thermostat, took 24 hours to get it to stabilize. Had 1 chicken egg in there also, which hatched last Thursday and the duck eggs are due to hatch tomorrow, I still had movement in 2 of them a few days ago. I believe these survived because of changing the fan direction I created a cool spot, I did lose 3/4 of the duck eggs at the time though. Also I have a digital thermostat controller that will be getting installed as soon as this batch is done to avoid any spikes like this again. I did some research and went with the Inkbird ITC-1000 for just a little over $17 each(ordered 2). From what I have read these are one of the better units available.

I have had pretty good luck with stable temps with the hot water heater thermostat up till this point but they are finicky with placement in relation to your heat source so they so they don't cycle too much or not enough creating spikes. I "saved" close to $10 initially by using one but after I lost about $50 worth of call duck eggs my savings aren't feeling so good anymore.

Many people who diy their own incubator are doing it to save $$$ whether it be to build an incubator as cheap as possible or build a high quality incubator without spending hundreds on a cabinet incubator. If you are thinking of building one I would really spend a few extra bucks to go the digital route as you have a probe that you put right where the eggs are at and regardless of other factors it "knows" what temperature you want because you set it, versus the hot water heater thermostat which doesn't "know" what actual number you are aiming for. I know people use them with great success and I had but I was always leaning towards this route and finally got the kick in the pants to force my hand. I also built a new cabinet style incubator I will be putting this in and using the old one as a hatcher only.

Wondering what other DIYer's are using and your results?

 

[careeka22]

My DIY is just a cooler, a 25W clear bulb and a digital hydrometer that reads temp and humidity. I had a fan all ready to install but found that temps were holding stable without one. I'm on my 4th hatch. First was 9/11, second 15/16, 3rd 9/14 and right now I have 23 looking good for this weekend. Here is a pictures of my setup. First 3 times I laid eggs down, doing a carton hatch this time. The only thing I have to watch is when the AC is on it can drop my temp some so I just put a towel over it and it keeps it warm enough.

 

[NAA60512]

I have the ITC-1000 and the STC-1000. They are extremely popular and both controllers have been used to hatch an uncountable number of eggs. I have used both controllers successfully and I do not mean to disparage anyone's choice to use either controller. I became dissatisfied with both controllers for several reasons:

1) the STC-1000 and ITC-1000 can only be set in one-degree increments. If I would like to set the controller to 99.5 F (37.5 C) I cannot do that. No big deal but the inability to set a digital controller to a tenth of a degree, especially a digital controller that displays tenth-degree increments, was very frustrating to me. It was like, false advertisement or something.

2) the built-in hysteresis or dead band of one degree in conjunction with the heating element I was using (more on that in a moment) created a regular incubator temperature variation of 3.5 degrees. With a setpoint of 100 degrees the actual operating range of the circuit was 99-101 degrees, one degree above the setpoint to one degree below the setpoint. This built-in dead band keeps the controller from rapid switching which could lead to premature component failure. In my old incubator with a resistance-coil heat source the thermal drift of 3.5 degrees was unacceptable and again, very frustrating to me.

3) the ITC-1000 and STC-1000 are "dumb" thermostatically-controlled ON/OFF switches. They either apply full power to the heating element or no power to the heating element. When the controller energized the heating circuit the heating element had to warm up before it could affect the incubator temperature. During this warm-up period the incubator temperature would continue to fall. The heater would eventually catch up and raise the temperature until the temperature exceeded the setpoint of the temperature controller, at which point the controller would de-energize the circuit. Although de-energized, the heater would continue to radiate heat into the incubator until it cooled down, which means the temperature would continue to rise. Ever touch a light bulb that has just been turned off? Even though the bulb isn't illuminated it is still hot and radiating heat for a short while. Lots of examples come to mind, frying pan on a stove, bad "ever see a match burn twice" jokes.

I wanted the option to set my incubator in tenth-degree increments and I wanted proportional control, like the cruise control in a car. Going up a hill requires more power to maintain the setpoint (speed, in this example). Going down a hill requires less power to maintain the setpoint. Proportional–integral–derivative controllers (PID controllers) used as digital thermostats work exactly this way. Raising the incubator temperature requires more power, lowering the incubator temperature requires less power. Broadly speaking, a proportional–integral–derivative controller "learns" the system or process it is controlling via feedback loop and only supplies the power necessary to maintain the setpoint temperature. None of this "all or nothing" nonsense. PID controllers are also very reasonably priced. As of this writing one can purchase a PID controller on Amazon for the same price as an STC-1000 or ITC-1000. I am surprised that more people do not use them in their DIY incubators since they provide continuously modulated, precise temperature control.

I ditched the old heater for a system with very little thermal mass which means I do not have to deal with a lot of thermal drift. My temperature variation is generally two-tenths of one degree now.

 

[Old McRonald]

My DIY is just a cooler, a 25W clear bulb and a digital hydrometer that reads temp and humidity. I had a fan all ready to install but found that temps were holding stable without one. I'm on my 4th hatch. First was 9/11, second 15/16, 3rd 9/14 and right now I have 23 looking good for this weekend. Here is a pictures of my setup. First 3 times I laid eggs down, doing a carton hatch this time. The only thing I have to watch is when the AC is on it can drop my temp some so I just put a towel over it and it keeps it warm enough.

That is great you're getting those kind of results, far better than what I've had with my still air. If I got those results I wouldn't change a thing!

 

[Old McRonald]

I have the ITC-1000 and the STC-1000. They are extremely popular and both controllers have been used to hatch an uncountable number of eggs. I have used both controllers successfully and I do not mean to disparage anyone's choice to use either controller. I became dissatisfied with both controllers for several reasons:

1) the STC-1000 and ITC-1000 can only be set in one-degree increments. If I would like to set the controller to 99.5 F (37.5 C) I cannot do that. No big deal but the inability to set a digital controller to a tenth of a degree, especially a digital controller that displays tenth-degree increments, was very frustrating to me. It was like, false advertisement or something.

2) the built-in hysteresis or dead band of one degree in conjunction with the heating element I was using (more on that in a moment) created a regular incubator temperature variation of 3.5 degrees. With a setpoint of 100 degrees the actual operating range of the circuit was 99-101 degrees, one degree above the setpoint to one degree below the setpoint. This built-in dead band keeps the controller from rapid switching which could lead to premature component failure. In my old incubator with a resistance-coil heat source the thermal drift of 3.5 degrees was unacceptable and again, very frustrating to me.

3) the ITC-1000 and STC-1000 are "dumb" thermostatically-controlled ON/OFF switches. They either apply full power to the heating element or no power to the heating element. When the controller energized the heating circuit the heating element had to warm up before it could affect the incubator temperature. During this warm-up period the incubator temperature would continue to fall. The heater would eventually catch up and raise the temperature until the temperature exceeded the setpoint of the temperature controller, at which point the controller would de-energize the circuit. Although de-energized, the heater would continue to radiate heat into the incubator until it cooled down, which means the temperature would continue to rise. Ever touch a light bulb that has just been turned off? Even though the bulb isn't illuminated it is still hot and radiating heat for a short while. Lots of examples come to mind, frying pan on a stove, bad "ever see a match burn twice" jokes.

I wanted the option to set my incubator in tenth-degree increments and I wanted proportional control, like the cruise control in a car. Going up a hill requires more power to maintain the setpoint (speed, in this example). Going down a hill requires less power to maintain the setpoint. Proportional–integral–derivative controllers (PID controllers) used as digital thermostats work exactly this way. Raising the incubator temperature requires more power, lowering the incubator temperature requires less power. Broadly speaking, a proportional–integral–derivative controller "learns" the system or process it is controlling via feedback loop and only supplies the power necessary to maintain the setpoint temperature. None of this "all or nothing" nonsense. PID controllers are also very reasonably priced. As of this writing one can purchase a PID controller on Amazon for the same price as an STC-1000 or ITC-1000. I am surprised that more people do not use them in their DIY incubators since they provide continuously modulated, precise temperature control.

I ditched the old heater for a system with very little thermal mass which means I do not have to deal with a lot of thermal drift. My temperature variation is generally two-tenths of one degree now.

I have not installed my ITC-1000 yet, but from looking at the display pictures I assumed I would be able to set it to the tenth of a degree since the resolution is to a tenth of a degree, it will still be a great upgrade to my hot water heater thermostat. From what you're saying about the PID controller it sounds basically like a light dimmer that adjust itself to maintain the setpoint. Could you post a link to the one you have?

 

[NAA60512]

I also assumed that I would be able to set the temperature in tenth-degree increments. The ITC-1000 displays in tenth-degree increments but you cannot set the controller in tenth-degree increments. A PID controller is a bit more than a rheostat (a light dimmer). The PID controller that was (almost) the same price as the ITC-1000 is here. There are more than a few PID controller options.

I chose to go a different route and purchased a Herpstat 1 controller from Spyder Robotics. When I was doing my research before building my cabinet incubator I realized that, of the folks who use digital temperature controllers, the reptile and amphibian folks were very good at continuous temperature and humidity control. Keeping a $500-$1000 snake or rare frog/amphibian alive could be pretty important. I know that sort of temperature control isn't for everyone (too expensive).