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Suppliers and Resources Area => Gardening Resources and Links => Topic started by: munnharpe on May 08, 2014, 12:25:10 AM

Title: I want to make my own thermostat
Post by: munnharpe on May 08, 2014, 12:25:10 AM
Hey!
I want to make my own thermostat that I can stick into the substrate of some container.
I have an incubation chamber for growing mushrooms, and I want the temperature in the substrate inside the incubation box to be just right.
In order to do that I wish to either buy or build my own thermostat that I can stick into the substrate and that will turn on and off the aquarium heater that I use.

It could for example be similar to how a timer work.
You put it into an electrical outlet and you put the thing you want to control into the thermostat.
Then a wire with a thermal sensor in the end could be put into the incubation chamber and into the substrate.

Does anyone have any tips?
Title: Re: I want to make my own thermostat
Post by: Saros on May 08, 2014, 12:35:31 PM
I hadn't actually used one of these but you might try something like this...
http://www.dx.com/p/xh-w1208-1-8-lcd-digital-temperature-controller-grey-110-240v-234991#.U2tdJtMpDFo
Title: Re: I want to make my own thermostat
Post by: SoulGrower on May 08, 2014, 03:09:54 PM
I used to use Ranco thermostats when I used to service aquariums.  A little pricey ~50-75 usd, but I can vouch for their reliablility.  Otherwise, I would second the one suggested by Saros.

Either way, I would highly suggest calibrating... which can be difficult due to discrepancies across products.  I was always amazed that we could buy a box of thermometers, all the same brand and model, and they would have a variance amongst themselves of upwards of 5 degrees!  When you find a temperature that is just right for whatever you are growing/keeping, use a thermometer (or two or three) to take a reading.  Keep THAT thermometer and mark on it where your sweetspot is.  It is now your reference.  Then use it to calibrate your thermostat (don't believe that just because the thermostat is set to 77 F that it is actually 77).  Adjust the thermostat until it regulates at your sweetspot.  Point is, don't believe any thermometer or thermostat is actually reading the true temperature (unless your ready to drop a whole lot of coin.. and even those need calibration).  Just use them as a point of reference.
Title: Re: I want to make my own thermostat
Post by: munnharpe on May 08, 2014, 07:44:24 PM
Thank you both for your good tips! =)
Title: Re: I want to make my own thermostat
Post by: happyconcacti on May 26, 2014, 05:44:47 PM
I used to use Ranco thermostats when I used to service aquariums.  A little pricey ~50-75 usd, but I can vouch for their reliablility.  Otherwise, I would second the one suggested by Saros.

Either way, I would highly suggest calibrating... which can be difficult due to discrepancies across products.  I was always amazed that we could buy a box of thermometers, all the same brand and model, and they would have a variance amongst themselves of upwards of 5 degrees!  When you find a temperature that is just right for whatever you are growing/keeping, use a thermometer (or two or three) to take a reading.  Keep THAT thermometer and mark on it where your sweetspot is.  It is now your reference.  Then use it to calibrate your thermostat (don't believe that just because the thermostat is set to 77 F that it is actually 77).  Adjust the thermostat until it regulates at your sweetspot.  Point is, don't believe any thermometer or thermostat is actually reading the true temperature (unless your ready to drop a whole lot of coin.. and even those need calibration).  Just use them as a point of reference.

Furthermore, the calibration isn't always linear with these thermostats.

I use Hydrofarm thermostats (http://www.amazon.com/Hydrofarm-Digital-Temperature-Controller-Heat/dp/B0047KKOMI/ref=sr_1_2?ie=UTF8&qid=1401118934&sr=8-2&keywords=hydrofarm+thermostat) and they appear to be more accurate at the higher end of the temp range (~100F) and worse at the lower ends (~70F)

Also, just because a thermostat is digital does not mean its more accurate.

Hcc