Problems with homeade egg thermometer. Please Help!

[Jed]

Total chicken rookie here so I will say sorry in advance for any stupid questions that may follow.

I built a homeade incubator using the standard styrafoam cooler/light bulb/pc fan/water heater thermostat model. Made my own egg thermometer using an egg shell filled with dish soap, put the probe in and used hot glue to seal the hole. Did a trial run to see if the incubator would get to the proper temperature and humidity. All was well for the first 12 hours. Shortly thereafter the temperature from the probe spiked to 131 degrees F! I have a second cheap non digital thermometer in the incubator which was reading 100 degrees at the same time. Not sure which thermometer was correct I picked the homeade egg thermometer up and it did not feel like 131 F. I believe 130 is the temperature at which skin begins to burn. I had read other posts where people say to calibrate the thermometer but not sure how to do that and the paper work that came with the thermometer did not have instructions on how to do so. I disassembled the egg thermometer and let it cool to room temperature and there is a difference of 31 degrees between what the indoor and out door temperature readings. I concluded the digital thermometer was not accurate and the probe portion of the thermometer was broke. I purchased a second digital thermometer with a probe, that was made by a different company and made another egg thermometer. However, this time instead of using an egg shell I used a ping pong ball figuring it would be close enough. After approximately 18 hours I am having the same problem as I had with the first egg thermometer however I am only seeing a temperature difference of 14 degrees. The first thermometer was an Acurite brand used in a lot of the homeade incubaters i saw on this website and the second is a Springfield brand. Could the problem be the liquid dishsoap media I am filling the egg/ping pong ball with? Has any one else expierenced this?

Also just wanted to say I love this site and have been addicted to it since I found it two weeks ago! I think my wife thinks I am going chicken crazy!

 

[paddock36]

Wish I could help but I've never used the egg thermometers. My incubator is also homemade and I just use one of the digital thermometer/hydrometers. I have hatched several batches of chicks and a friend of mine hatched out some last minute refrigerated duck eggs and it worked fine without an egg thermometer.

 

[muddstopper]

Did you remove the plastic covering on the external sensor probe. Evey one i have taken the cover off of one, it would become more temp sensitive and have a faster response time to any temp fluctuation. They all also looked like the little sensor was encased with a silicon product. My guess is that the dishsoap is what is causeing your problem. The actual sensor, which probably looks like a little blue capacitor, works off resistance to voltage. I suspect that the soap is effecting the resistance properties of what ever material the resistor is made from. In addition, the sensor will have exposed metal resistance wire pertruding from the sensor. These little wire prongs are for attaching the electrical wire between the sensor and the meter. Liquid soap penetrateing the insulation of these little wire prongs will also effect the resistance levels by conducting electricity between the two prongs. High temperature reading would be a side effect of this reduction of resistance. If you are going to build a eggometer, I suggest that you use a non-conductive material to fill the egg to reduce any chance of conducting voltage which will effect temperature readings.

 

[BirdBrain]

I used hair gel to fill my egg shell and it worked well.

 

[Jed]

I did not remove the plastic cover. I would think hair gel would be conductive as well. So would something like sand work to fill the egg up with? I am still seeing a 30 degree difference even after I removed the probe from the soap. Maybe there is still soap inside the plastic probe? I believe the packages for both probes stated they wear weather proof. They must not be soap proof! I will remove the plastic cover when I get home from work tonite and give an update.

 

[muddstopper]

Quote:
I think i would leave the little cover on the sensor if I was makeing a eggometer. Taking the cover off will result in a loss of weatherproofing. Someone once suggested using a electrolite nonconductive grease to fill the egg shell. Supposed to be able to buy it at Lowes or Homedepot in the electrical section. Personally, I just lay the probe in the egg tray along with the eggs.

 

[Jed]

Investigated this a little further by disassembling the probe. The so called "weather resistant submersible probe", was not fully sealed. When I took the probe apart there was dish soap inside the probe. This is good to know and thank you Muddstopper for your thoughts and knowledge.

 

[ArizonaDesertChicks]

This same thing just happened to me - I have my test egg filled with antibacterial soap (which I read was successful for someone else) and after only 3-4 hours of putting the probe from the acurite thermometer into it, it spiked to 138.4. My springfield is measuring 100.2 and the "inside" temperature on the acurite is 100.4 (I'm positive the 138 is wrong). I think the probe is no good for putting into wet places. Did your probe (outside temperature) go back to normal after you dried it out, or was that part of the acurite ruined.

One more question about the acurite - does anyone know if there is a way to keep the "inside" temperature on display. I did read the instructions, but they were no help. My acurite insists on showing the time and I can't see the inside temp without reaching my hand inside the bator and pushing a button. The outside temp (which may now be broken) and the humidity are also on display, but I would really like to see the inside temp without having to open up the incubator.

 

[silkiechicken]

If the tip of that probe is a thermistor (measures temp based on a change of resistance in the wire) .... putting it in water is probably shorting it out. There are other methods of measuring temps so not all electronic devices are the same.

I personally think it's more time consuming to make one than it is worth. All bators have temp gradients and evaporation of water from the egg during incubation does cause a decrease of temperature in the egg compared to the surrounding. (Test this concept by measuring the temp difference of two cups of water in the bator, one covered and one open.) Plus, once the chick develops, it begins to release metabolic heat which can't be accurately measured in a stationary probe. The thermostat in the bator just needs to maintain the air temp at near ideal for a great hatch.