Night/Day Twin Variac Digital Fan Controller with External Temp probe & room monitor

Hi all,
I know there are many threads with variac fan controller designs to rid us all of the terrible fan hum from fans 6" and above that the standard fan controllers create.
I have designed a Twin variac fan controller with an external temp probe for placing where ever...and a secondary internal room Temperature thermostat also (You select which to use to monitor temps). With this design you can also set lights on and lights off temps.
Wireless probe and Temp controls anyone ? VERY SIMPLE
Designed and I know it works due to my background.
Airforce equivalent is around £350 with no dual thermostat and no Night/day feature.
I've calculated the costs with NEW components @ around £180 but am on ebay at present and I know it is possible to build for under £100 @ a push and the correct auction

Is this worth posting?
Anyone interested ?
I'll do a full on IDIOT guide with pics.

Night/Day SILENT Dual variac, Dual thermostat fan controller with wireless controls gotta be a winner even @£180 (single varirac controllers with no thermostat etc cost £120 plus)

Design choices are at present to keep cost low:
Dual thermostats OR single wireless thermostat(movable to monitor the location of your choice)
Currently working on a dual wireless (Done but not convinced of it's quality/needs improvement)

I'm in for an idiot guide.

Update:
We have a winner.
2 x Carroll & Meynell CMV2F1 variable transformer 2A variac.


£31 for the pair...... via ebay...... luckily someone died
This is an amazing price considering:
1) Price of copper at the moment
2) New they retail @ £63.45 EACH via RS. Cheaper versions available at Wattbits.... but still not £31 for 2.
All specifications are available via the link above.

Next on the list is the digital thermostat and probe.
(Seller playing hard ball at moment)
Looking like overall cost may hit £80 for this variac controller design.
Once all parts have arrived I shall post FULL electrical circuit design and pics for both the wireless model and the dual thermostat model fan controllers.
Closely followed by the idiot guide.

Just noticed .......
Prices of variacs are varying almost daily @ some outlets. I am assuming this is due to the price of copper. Wattbits just went up £4 over night.

that's some overpriced overkill shit for just a fan controller IMO i payed 12$ for mine no thermostat needed, i mean it's a fan not an A/C or heater, no thermostat can really control temps...

zem said:

that's some overpriced overkill shit for just a fan controller IMO i payed 12$ for mine no thermostat needed, i mean it's a fan not an A/C or heater, no thermostat can really control temps...

Click to expand...

Talking rubbish mate. You can control temps VERY accurately with thermostats. Even the most cheapest of stats are quite accurate.
Your $12 controller on a fan over 6" when not at below 20% or above 80% power will make the fans hum to feck.
It also adds wear to the fan.
VARIAC controllers SILENCE THE HUM they are the only controllers that DO. They also help your fan last longer.
Before posting such a ridiulous statement maybe you should read up on FANS.... CONTROLLERS ......Thermostat's.

your talking 100 british pounds i can change 10 6" fans with this cost. not talking rubbish i clearly said IMO and once you get a good fan it will last years anyway, mine has been the same fan for 5 years lol and it still doesn't hum loud at all until this day. really if you spend 100 pounds on a fan controller it's the most overpriced and overkill fan controller i have ever experienced, crap you could get a dehumidifier for close to that, but it's your pockets you're emptying so feel free to do it, i was only trying to help

10 x 6" fans of quality for 100 GBP my arse.
Find me anything like RVK or ruck or airforce ........or any quality inline fan where you get 10 for £100.
Think you ment control
But that aint possible either.
Any quality fan that can move good volumes of air run at less than 80% or over 20 Hums.
As for most overpriced...... christ man you obviously ain't looked around there are controllers out there that would give you a stroke if you heard the price from the sounds of it.
But....IMO quality maybe isn't your thing LOL.
If I didn't think this WAS cheap for the quality AND for what it actually does for you... WTF would I post it...... for that matter why would the other X number of variac posts be made .......not just here but EVER other Grow related forum.
Opinion is fine mate but that least base it on having some knowledge of the topic.

ok maybe not 10, there's one http://www.smarthome.com/3011/6-In-110VAC-250CFM-In-Line-Duct-Fan-DB200/p.aspx 34$, 10b.p. = 16$, fan=20b.p. still not making sense to me paying 4x the price of a fan for a simple fan controller, the very expensive ones may be maybe for huge rooms and serious exhaust and the regular ones with a fan last for many years... anyway obviously you're getting it anyway and it's your thread, then i must say, great buy! i'm out

That fan sucks...... build quality poor.... paper thin. crap capacity for a 6" lol

Yeah those duct booster fans are a different class than a solid inline fan capable of moving real CFM. I'm not considering anything less than a 6" 400+CFM unit for my room. I don't want it humming and I don't want to burn it out prematurely. My concern would be whether the cost is worth it for you Hillcrest, other than the DIY satisfaction. I've seen day/night fan speed controllers online for $65USD.

I use this controller http://www.growwurks.com/c-a-p-controllers-vsc-dne-variable-fan-speed-contoller-day-night.aspx and it does an excellent job managing my Vortex 6" 450 CFM fan. This fan moves some air! It usually runs at under 20% at the moment with no horrible hum. That being said I am very interested in seeing how you put it together and how it works for you.
I think anyone that is willing to take the time to do a DIY thread with an idiot guide and of course with pictures should be commended even if it may be overpriced in your eyes.
Threads like these inspire people to improve, modify, and come up with better solutions to the common grower's problems.
Please continue your thread so that we all can become more empowered in our endeavors!
P.S. I do love how people pass inline booster fans off as High Output inline fans The CFM ratings on booster fans are with no resistance what so ever and once you introduce any sort of resistance, like the fan alone in some duct work, the CFM's drop dramatically by half or more most of the time.

That's the one I was referring to. Didn't know if I should post the link considering the man is trying to build one, possible for resale. So Pazu, it works will with your 6"? Does OP's build have components that would contribute to a longer fan life? I guess what I'm asking is does the unit above lack something?

Idiot guide ?

I like my variac.....but your getting into PLC budget territory

- Jiji