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thermostat,humity, snesor, display etc

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New Member
I am a total Newbie to electronics, but I am old enought to know better than to start asking a bunch of dumb questions without doing at least a little research so I went here first, http://www.electro-tech-online.com/threads/new-to-electronics-f-a-q.41146/ . I'm an old man not likely to learn all this stuff in time to be of any benefit to me. So with that said, here goes.

As a hobby, I fool with chickens, mostly for personal consumption. Anyways, A buddy of mine helped me build a dandy incubator. A few chicken friends saw it and decided they needed one too, so we started building them. easy enough to do, make a wooden box, a $15 electric heater and a plastic tray to hold water, the rest is simple mechanics, tray to hold the eggs, fan to circulate air, etc. etc. Someone posted a picture of it on a chicken forum and now everybody wants one, BUT, they want fancy. Digital temperature readout, electronic thermostats, humidity sensors,. Way out of my league of know how to build or design.

Here is where I hope some of you might be able to help out. What I am looking for is a sensor that can measure temperature, humitity, or both, that can be hooked by using wires for mounting inside the incubator and connect to a digital readout that is mounted outside the incubator cabinet. Ideally, the readouts would be measured in 1/10 degrees and +/-1% Rh. Also a thermostat that can handle 120v, 400w that can uitilize a probe so thermostat is mounted outside the incubator. Ideal temps are 99.5degrees and humitity 40%-70%. thermostat needs to regulate on/off at or near 1degree or less.

I know nuthing about programing chips, or building circuits, heck I'm an old man fooling with chickens, but if someone can point me in the right direction, I'll get the grandkids to do the soldering, at least they can see those little parts. Or if someone is willing to build this circuitry for me, I'll pay a reasonable price.



Well-Known Member
As a hobby, I fool with chickens
I'm not sure that's something I'd be telling anyone about..

As far as your readout goes, you may be able to get a premade weather station which will display the required details. There's a few cheapies here: DealExtreme: Search for humidity (66 products in 21 categories). The thermostat would then be a separate cct., which anyone could design for you.

If you want to do the whole thing yourself from scratch, you'll need to track down some temperature and humidity sensors. Sensiron produces them, see Digital Humidity Sensor SHT15 - High-quality relative humidity sensor for demanding measurements - Sensirion AG, and possibly ask for a quote for whatever quantity you require. I'm guessing that there's also a raft of other companies that produce them. I have no issues with helping you design the thing, should you wish to go in that direction.


New Member
Another question coming up on my side:

What should the 400W for the heater be good for? With 400W you can slowly dry the eggs or fry a chicken, depending on the volume of the incubator - oven?

Are you located at Alaska?

Also, maintaining a breed temperature at an accuracy of ±1degree or lower isn't natural. Hens leave their nest every once in a while to pick some food. In the meanwhile eggs cool a bit, and despite cooling hens produce chicken.

Humidity will be an issue if it is below 20% (like in Death Valley). Chicken breed at every place in the world, even in Thailand, where the RH normally is 95%.

Disregarding a humdifier the circuit should be cheap to make. Instead of using controlled water vapor (including a humity sensor and the control circuit) a bowl of water being slowly evaporized should suffice.

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Active Member
easy enough to do, make a wooden box, a $15 electric heater and a plastic tray to hold water, the rest is simple mechanics, tray to hold the eggs, fan to circulate air, etc. etc. Someone posted a picture of it on a chicken forum and now everybody wants one, BUT, they want fancy. Digital temperature readout, electronic thermostats, humidity sensors,. Way out of my league of know how to build or design.
seems to me that you've started easy and went for the harder stuff. Like Boncuk said, the surrounding parameters aren't too important because the hens themselves ARE the regulators for the conditions already.

I don't know.... you might want to tell why in the first place you wanted the weather parameters to be displayed? Other than being fancy. Here in Malaysia, chickens are given small 'houses' or 'reban ayam' in Malay, meaning chicken shelter, and the chickens themselves manage their 'household' logistics. :D


New Member
I see I need to give a little more information.
First there are no hens involved when using an incubator, just fertile eggs. If one wished to rely on the hens to decide to go broody, you might only get one or two hatches a year. Also, a hen is limited to just how many eggs she can cover and hatch. The incubator is designed so that I can set and hatch eggs when I want them without relieing on the hen to do the work. Currently, Our large model incubator can hold 300 eggs in the turners and a additional 100 in the hatching tray at any given time. Way more than one, two, or even a dozen hens can hope to try to hatch at one time. Smaller models only hold 50 and there are models that only hold one egg at a time. There are dozens of incubator companies out there selling similar to what we sell. Some incubators holding thousands of eggs at a time. These are mostly for commercial growers. We are targeting the backyard chicken community, the get back to nature crowd. To successfully hatch eggs, even with a hen doing all the work, you have to have a rooster. Many large communities no longer allow roosters because of the crowing. For this reason, one must find fertile eggs and incubate them themselves, which is why the demand for small, hobbiest size incubators. Growing Backyard chickens is the fastest growing hobby in the US right now.

As for the electronics, yes I can purchase a electronic thermostat from one of the other incubator companies. The cost is around $80 before shipping and Taxes, but then our incubators would be nothing more than a copy of all the other incubators on the market, except for a fancy cabinet. The 120V, 400W thermostat is the specs given for one of their Thermostats. The purpose of maintaining a narrow on/off cycle is to prevent getting the eggs to hot or allowing to get to cold. Temperature is very important in incubation times. A hen will hatch eggs in 21 days, by not regulating temps you can hatch out to early as in 18 days, or late as long as 24 days. This results in deformed chicks. The heating element is nothing more than one of those coilspring looking heating elements found in common space heaters, I have even seen a lightbulb used for a heat source. Currently ours cycles every 3.5 minutes and stays on for only 17 seconds. The fan is continuous and circulates air for even temps. A digital thermometer/hygometer from Acurite ($12 from any hardware store) is used to monitor temps and humity. Some use a Wetbulb hygometer. Nothing fancy. I have even seen hot waterheater thermostats used to regulate temps.We use colored LED lights to tell when everything is on. Now the problem with this type of setup is that the digital thermometer/hygometer has to be placed inside the cabinet, next to the eggs for accurate readings. This necessitates opening up the cabinet to read and a resulting loss in heat as well as humity. What I am wanting is a digital readout display I can mount on the outside of the cabinet connected by wire to probes or sensors, that can be placed inside the cabinet. A digital programmable thermostat, that can also be mounted on the exterior. And something that is powered by a normal 120v outlet found in every home. Most of the home models for furnaces are 24vDc and would require inverters to operate. And since the thermostat control needs to be mounted outside the heated area, either a sensor probe, remote wireless transmitter, or something, would be needed to read inside temps.

I hope someone here can make sense of what I am describing and wanting to achieve. Of course cost is going to be a big consideration, but when one factors in a ready made electronic thermostat and a seperate digital thermoter/hygometer, we are already looking at around $100, plus its two seperate units. I need and all in one unit for less than $100, plug and play. How many I will need is only guessable, but considering the demand, and the fact these features are only available on the very high end machine, I can see a market of people wanting to upgrade their current setups.

Currently we are custom building these incubators one at a time in our garages.. They where posted for sale on an internet forum (similar to this one) this week and we recieved 4 orders the first day. Whether this will turn into a much bigger business is yet to be determined, many factors to consider. Maybe we will only need one or two thermostat units, or could be hundreds. Time will tell. Build a better mouse trap and they will come.

By the way, since this is only my second post, my replys are being moderated resulting in delays to my posting and recieveing replies. Forgive me if it seems I am slow replying to your answers.



New Member
Ok, I found this, Thermostat Electronic Kit MK138 and supossely with a few modifications it will work with the temps I am wanting to regulate. Here are the mods, tell me what you think.
There are 4 resistors to change, R4, R5,R6, R7.
Change to
1k horizonal potentionmeter-UH00

Now if someone wants to take a look and see if this will work for the thermostat, to keep temps in the 99.5 degree range. I would appreciate it. We can work on the digital later.


Well-Known Member
Do you have a schematic? Hard to advise parts values based on a photo of the kit PCB.

But it does look like a comparator thermostat with a relay. I'm sure you can fiddle with the resistors to set the temperature range you like.


Well-Known Member
It's a very simple comparator temp controller.

Just hook it up, you will probably find the adjustment will already reach your target temperature. If not just change R5 or R6 so it does.

And it might need the temp sensor fairly close to the heating element.



New Member
projects that might help

you might want to checkout several of the projects web sites that may help you in cheap affordable projects for you and your buddies. Now, some of these site might be too advance for you, but i will label below which are too advance for ya'll ...Make sure when you go into the site select Measurements in the catergories so it will take you to what you are requested.

1) Electronics Lab - Home farily easy project that require little electronics exp. and at a very cheap cost.

2)www.circuitlakes.com ((Very advance electronic projects( but might give better ideas what you might offer your backyard friends and customers)

3) www.coolcircuits.com fair to hard project but easy to build if realy needed

4) http://www.elecfree.com :: Circuit Project Electronics ...my favorite as I make alot of experimental project from here

hope i can help with this info as you may find what you are looking for. most sites have plenty of projects that you requested.if you need more just email at [email protected] or [email protected]

glad to help!


New Member
I appreciate the reply and the links. Since I am not a electronic type of person, I have chosen to pay a professional to design and build this unit. I cant see to soilder little bitty parts anyways. Thanks again and the person I found to build my circult did come from the membership of this forum.
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