Cheap fan controller for lights

The goal:
I run a 12x8x7 cge room. It goes without saying that a cge environment is rather expensive to operate from an electricity standpoint. Quite necessary though if I want to grow in my garage during the summer months in sunny southern cali. while maintaining a consistent environment.
So during the winter months (low ambient temps as well as very low humidity) I decided to turn the ac of and control my temperatures with a light fan controller. BTW, it is also very easy to build a host of other controllers, i.e. exhaust on on humidity rise, co2 off on exhaust on, switching from exhaust to ac on ambient temperature rise etc.


Scope:
1. fan controller for light during winter months
2. controlled by temperature rise or fall
3. under $20 + cooling/combo t-stat

Sequence of operation:
1. control circuit closes on temperature rise (cheap cooling t-stat)
2. control circuit switches relay thereby powering exhaust fan (or any load)
3. control circuit opens once temperature drops below set point, thereby switching relay back and turning load (fan) off

Items needed:
1x transformer 120/24
1x relay 120/24
1x receptacle with box
1x pig tail

Build time:
Under 1 hour

Results:
Maintains temperatures during lights on within 1 degree F.

If anyone can use one of these send me PM and I'll draw up a diagram

Kind

I would like to see it, but you should share it with everyone. I don't think I've ever worked with a transformer but I do a lot of DIY. Basic to intermediate electrical, gas lines, and tankless water heater co2.

right on, you should just post up the pics and whatever. im sure others would be interested. there are a few techy DIY'rs here on RIU, they have no problem posting their creations for us.

Most def show a diagram. I'm interested

Sorry guys, was busy at work. So here is my disclaimer: Only do this if you have a basic understanding of electricity!

What we are doing is very basic.
Build a control circuit that is capable of switching a load (fan etc.) on and off.

A control circuit is typical a low voltage circuit. I'm a HVAC contrctor, so I will use a 24v circuit, mainly because I have those components laying around (they are commonly used in my industry). I'm sure if I looked around I could find 12v components as well.

Things to scavenge for:
1x 120v/24v Transformer
1x Old Power Cord (w.ground)
1x Old T-Stat (combo or cooling)
1x Relay 24v (needs to be able to handle the amperage of the load)
1x receptacle with box
2ft romex
some wire connectors

Ok, some things to consider:
Note the 3/4 contacts on the relay. they are closed while the control circuit is open. This means that we could certainly use the 3/4 contacts to power an additional load i.e. co2 controller/solenoid. Let's say some use their hood to also vent their grow space, but want to also use co2 without sucking it out while venting, here is how we can easily do this: Use the 3/4 contacts on the relay to power an additional receptacle (load). Sequence of operation would be as follows. 1. while the control circuit is open (exhaust fan off), the 3/4 contacts are closed (hot), let's power a co2 controller/solenoid with this. So, now we are supplementing co2 while the exhaust fan is off. Now, let's say our temp rises above the t-stat set point, let's say this set point is 83f. Now as the t-stat closes (83f), the relay will switch over to the 5/6 contacts, thereby opening the 3/4 contacts, thereby turning the fan on and switching the co2 off. As the temp drops again this cycle reverses.

nice writeup. Can you provide a few pics of your setup?

Weedasaurus said:

nice writeup. Can you provide a few pics of your setup?

Click to expand...

Cheers
Well, I'm not so sure if it is a nice write up, judging by the response lol. Either it looks too complicated or people do not understand the potential this type of controller has in a grow room
Especially since we are using mechanical relays instead of solid state.
I'll take some pics later.
Peace,
Kind

yes, thats why pics are important. it helps explain it alot more to newbies like me.

Excellent DIY!

I'm planning to implement this type of setup on the micro scale.

this looks intense. I'm a racer and have some understanding of electricity but your drawing if over my head. Like others said post pics of the finished product and step by step if you have time it will be appreciated by all