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Custom Ventilation System

  • #21
hey homer , i can see that you are using an old computer fan . i'm just wonering , i got a ton of old ones but they have no plugs , can you help me a bit with this electrical stuff like tell me what you did to give it something to plug for power ?
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  • #22
As it turns out my fan runs on AC current.  I guess I got lucky when I picked it up from a demolition construction site I worked at last August.  My fan is old-school.  Made in West Germany, but it works like a champ.  Good German engineering is the key it seems.  

I do have 12v DC fans at my disposal as well.  I'm working on creating a peltier system and am trying figure out how to plug them in myself. So far, I'm planning on hooking them into an old PSU (computer power supply).  The trick is to get the PSU to think its connected to a computer, until then it (psu) won't turn on. Casper knows exactly how to do this...

So, goldtrap2690, get yourself a ATX PSU if you don't have one already, and hope someone tells us how to get it to "fire up" w/o a computer present.

Could someone please post a reply and let us know how to do this?
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  • #23
Hi Homer,
I just finished work on a peltier system of my own, you should check out the thread: Electrical questions for several posts by casper. I am using an old (AT) architecture PSU, and it works like a champ! GOOD LUCK!!
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  • #24
I replied to Homer in an E-mail, but for anyone else wondering how to fool an ATX psu to turn on without being hooked to a computer here it is.

On the ATX connector (the longest one that connects to your motherboard) you need to jump the green wire with a black one (green = PSU on , Black = ground) there is only 1 green and multiple black.

You can either use a paperclip and jam it in the holes, or you can simply cut the wires and splice them if you don't plan on using the psu for anything else.


Casper
 
  • #25
Casper is correct. It is that simple to jumper the ATX to always being on.

Another option is to find a cheap older AT power supply.
 
  • #26
That is really a nice setup, Homer.
They say that imitation is the most sincere form of flattery, and I hope you agree. I am in the middle of creating a setup that is similar to yours.
I took a 10 gallon tank filled it with water. I have a airstone and a heater in the tank.
I have a 115v fan that I got out of an electric control panel. I'm going to take a piece of Plexiglas and cut a hole in it to mount the fan. Then I'm going to take a hose out of it to a new growroom I just built.
Since the fan will get it's intake from air outside the room, it will work for ventilation too.
I have some other ideas for it too that I'm not sure if it'll work. I'll have to experiment and see after I get it setup.
One idea that I have is to place a piece of Plexiglas in the tank, from top to bottom. The Plexiglas will be cut below the water line so that the water can flow through. I'll have the fan side airtight (except for the fan intake). This will create two chambers in the tank. As the fan blows air in it'll force it below the water and force it to come up in the second chamber and out through the hose into the growroom. That way it'll pick up the max. moisture and heat from the water.
Like I said that's just an idea right now, I'll experiment with it more after the unit is built.
Homer. Thanks again for the great idea.
 
  • #27
Thanks Ozzy.  I've noticed in my system that the fan does have some blow-back through the fan itself.  
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 I wonder if you might encounter the same problem, since you desire to push the water from one chamber to another. I hope that your experiment works for you.  Please let me know if it does or doesn't push the water.  

Does your exoterra fogger have any negative effect on any of your sundews, etc in your terrarium(s)?  I'm concerned that the sundews may not like the misting like other plants, such as heli or nepentes would.  

-Homer
 
  • #28
[b said:
Quote[/b] (homer @ Nov. 11 2003,4:17)]Does your exoterra fogger have any negative effect on any of your sundews, etc in your terrarium(s)?  I'm concerned that the sundews may not like the misting like other plants, such as heli or nepentes would.  

-Homer
Generally sundews will do fine in a light mist. Mine don't like it when my fog collects and beadup on thier leaves and they look like a wet noodle. If the air is moving and humidity is in the air rather than condensing on the plants I think you'll be just fine.
 
  • #29
Homer,
Are you still taking data on the temps and humidity and stuff? Im still interested in that info.

Thanks
Steve
 
  • #30
Homer I do have the same problem. Some air blows back though the fan.  At first I had so much air blowing back out of the fan, I thought I had the polarity backwards on the fan. Even with all the air backflow through the fan, I'm still getting quite a bit of air flowing through the exhaust. For my exhaust pipes I used two 1 1/4 inch pipes. I wished I had upsized to at least 1 1/2 inch, maybe even 2 inch pipe.
I think there are three things you can do to lessen the problem of the backflow of air. 1) Bigger or more exhaust pipes from the tank to your plants. 2) More air capacity in your tank. Either a bigger tank or lower water level. 3) A smaller fan. I think option #2 will have a limited, if any, effect on the problem. Why this is happening is because the fan is trying to blow more air into the tank than the pipes can handle. Over time it can burn the motor up on the fan.
I haven't tried to force the air under the water yet. Mainly because it's going to be harder to make the first chamber air tight than I thought. I had to cut out for the heater and the hose for the airstone.
When I first started it I put as much water as I could in the tank. I had less than a quarter inch from the water level to the exhaust pipes. That gave me about a 1/2 inch of air in the tank. I "wrongly" thought more water = more humidity. After I started the tank I realized it was the other way around, more air = more humidity. I started the tank Saturday night. and the water level have dropped pretty fast, I'm using a ten gallon tank and the water level dropped about 4 inches. I didn't record any humidity levels before I started the tank but I don't think the tank as helped very much. Since I have had the tank running the humidity levels have been between 50 and 80%. I want them near 100%. I'm hoping that as the water level drop even more, the air in the tank can hold more humidity and increase the humidity in the grow room. It may take a while because the grow room is pretty big. About 8 ft high, 5 ft deep and 4 ft across.
Today I changed it a little. I made the intake for the fan come from the grow room, that way it will be recycling the  air from the grow room and not using the dry air from the inside of my house. I hope that this will speed up the time it takes to build up the humidity.
I have thought about putting one of those small fog machines in the tank. Does anybody know if they are ok to use with cp's?
 
  • #31
I see.  I took readings yesterday of my system from the end of one of my exhaust tubes without the fogger running, and humidity level tapered off to 64% RH.  I inserted an airstone to see what would happen, and the humidity level stayed the same, give or take +/- 1.  I let the system run about 10 minutes to get accurate results.

My finicky fogger does not seem to run in distilled water, but runs just fine in tapwater.  go figure! That's why I ran the above experiment.  BTW Ozzy, the water level was about 3" during these trials.  

I also put a moist cloth between the 5.5 gallon tank and exhaust tubes.  The air flow was cut dramatically, even though the material was relatively thin.

Sorry Steve for the lack of data that you wish to collect.  As you can see, there are some issues using this method of ventilation at this time.  We still have some issues to iron out...
 
  • #32
Thats ok Homer, this is part of the data I am interested in.. not only the hard numbers but also the observations of the problems of the system.. I really like the idea and I am strongly considering implementing something similar in the near future, in the meantime I hope to take advantage of yours to gather data and observation
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Thanks
Steve
 
  • #33
Saw this post and thought i would add a little bit of info =)

Using an ultrasonic fogger to control the humidity in a terrarium is one of the most effective methods I have ever tried, and the most versatile.  I had a system set up almost identical to this that was the envy of every plant on the planet.

First off, the easiest place to get a fogger and accessories for the system is to order them from this page:

MainlandMart.com

They have may different sizes of foggers that produce lots of different amounts of fog depending on how big your terrarium is.  I use just the smallest one they have for my 20 gallon tank and I used the 5 disc fogger for my 75 gallon (fogger difuses 1500ml of water per hour!!!).   The other item they sell is a little bouy that floats your device at the surface of the water to maintain the maximum effectiveness of the device.  This is a NECESSITY!  you dont have to refill the water resivor hardly at all and you get the most dense fog this way.  

The system i built is a completely enclosed air filtration/humidity system.  I really wish i could photograph it, but it's all hidden in a custom cabinet, so i hope this will give you the general idea.

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It's fairly simple, but kind of big and elabrate if you are seeing it for the first time.  Starting at the water tank:  

10 gallon tank, filled about halfway with DISTILLED FILTERED WATER (absolute necessity!).  The ultrasonic water fogger sitting in a floating bouy to maintain it at the proper level for optimum performance.  the PC fan pushes air into the tank, thus pushing the fog out the pipe into the terrarium.  Using a larger pipe cuts down on the pressue so you get a gentle breeze laden with dense fog rather than a wet gale.  the terrarium is air tight, so the only place for the air to go is out the other side into another pipe.  since this is an enclosed system, there is suction being created on that end anyway, causing the fog to roll lazily through the plants and out the other side, avoiding the mist settling more than you want.  on the back end of the system, there is a fresh air intake, to regulate humidity and to refresh the air supply from time to time.  all i did was take a 2" pipe and cut vertical slits about 6 inches long all the way around it and fitted a 3" pipe over top of it.  this slides back and forth to regulate how much "dry" air is entering the environment to drop the humidity if necessary.   The fresh air mixed with the old humid air then passes through a simple air filter chamber to remove any agents that may cause harm to the system as a whole (dust, pathogens, dog and cat hair).  I used a clear acrylic box with 3 hepa filters used for furnaces cut down to size.  these need to be replaced yearly as they will get clogged and the chemical scrubers will loose their effectiveness.  The clean air then goes through the PC fan into the water tank and the cycle begins anew.  The fan is controled by a rheostat to regulate the flow of air through the system.  once again, you dont want a stiff breeze passing through your plants as that will stress them on a regular basis.  I like to keep the air flowing at a speed that will pass the air through the tank in about 10 seconds.   Powered by a standard PC power supply.
 
  • #34
drunknmunky,

Very impressive!  I have since changed my setup to a more simpler approach than what I have had before.  Here's my current setup: http://geocities.com/southsoundcarnivores/terrarium.html.

Anyway, do you grow sundews in this terrarium?  If so, how do they respond to the mist?  Would you be able to post a picture of the tank itself?

-Homer  
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  • #35
I dont have sundews in there actually, i am setting it up to be a vivarium for poison dart frogs with lots of tropical plants. I can not put up pictures as now, because it is in the process of "renovation" i am basically building a new habitat, but i will definitely post pictures as they come available.
 
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