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Are there any inexpensive humidity controllers??

PostPosted: Wed Apr 24, 2013 1:30 am
by tommix
I have a humidifier and a dehumidifier but the control knobs on them are pretty inaccurate. I am looking for a humidity controller to give me a little bit more accuracy, mainly for the humidifier. The ones I have found start around $80 and go up from there. Does anyone have a good source for one?

Thank-you

Re: Are there any inexpensive humidity controllers??

PostPosted: Thu Apr 25, 2013 3:01 pm
by Wunderdave
The dayton plug-in humidity controller on amazon is like $50 ish

You have to have mains electricity in your chamber though, some people aren't comfortable with that.

If you can hack together some wiring and an enclosure you can build one with a probe for cheaper, look on Ebay for standalone controllers, they look like PID temperature controllers. Ultrasonic humidifiers don't draw a lot of current so you might not even need to use an external relay to drive it, relying on the integrated relay in the controller instead.

Re: Are there any inexpensive humidity controllers??

PostPosted: Thu Apr 25, 2013 3:20 pm
by Wunderdave
If you want one with humidifying and dehumidifying capabilities, I think you may be stuck spending some extra dough.

Re: Are there any inexpensive humidity controllers??

PostPosted: Sat Apr 27, 2013 12:01 pm
by tommix
Thank-you for the info Wunderdave, I will look into the different options. Right now I am trying to get my PID to control the temperature like I want it to do.

Re: Are there any inexpensive humidity controllers??

PostPosted: Mon Apr 29, 2013 7:20 pm
by Wunderdave
Using a PID for a fridge may be tricky, PIDs function by using rapid on/off cycles and your fridge's compressor may not handle that kind of stress well.

Check to see if there's a setting in your PID for minimum cycle length and increase it to at least a few minutes if you can. The goal with a curing chamber is to maintain a range of acceptable temps, not a rock solid temperature line like with a sous vide setup for example.

Re: Are there any inexpensive humidity controllers??

PostPosted: Tue Apr 30, 2013 4:18 pm
by johngaltsmotor
Most PID controllers have a setting for simple On-Off control with a deadband. Wunderdave is right, you don't want to let the PID try to apply %power like they are typically used (so many 1/2 wave cycles on, so many off).

I have my deadband set at 3F so when temp is 3deg below target it turns on the heater until it hits target (or when 3deg above it turns on the refrigerator compressor).