DIY Thermostatic Fan Speed Controller

Hello there every1, how are we today?
I have been promising to do this thread now for a few weeks, and after some help with the wiring, ive cracked it. I havent included pics of every single wiring connection as not every1 will get the same thermostat as me, but i will show a diagram of the wiring for this thermostat for the folks who do.
Now, before we start, what exactly does it do?? It does exactly what it sounds like, it controls the speed of ur fan thermostatically. Basically, this little gizmo lets you lower the speed of your extractor fan for noise reduction/power conservation and if ur fan is just too powerful, and also if the fan you got for those hot summer temps is now too much in the winter. But whats good about this gadget is that by use of the thermostat, the fan can turn over at lower speeds, but when the temperature hits a predetermined level ((which is set by the knob on the thermostat)) the fan jumps into full power, and runs on full until the temperature drops back down below the level you set. This means that hopefully with a little adjustment, your growroonm should stay at nice steady temperauture, and you can relax safe in the knowledge that your green darlings are not being slowly cooked, but that ur fan is only using the electricity it needs to.

So, here we go, for this little project, you will need.....
1x Fan speed controller of your choice(i got mine from B and Q, it is a 250 watt model) Make sure you get a fan speed controller and not a dimmer switch if you are getting your speedo from a DIY store, if it hasnt got a fan printed on the knob its a dimmer!!. You can also use a speedo made by ur fans manufacturer if you wish-but check the wiring.
1x Cooling thermostat ( I used a Danfoss RMT230 heating/cooling stat, the honeywell T6360 is another recommended one, the wiring plan for which can be found at uk420).
1x Plastic rectangular junction box, big enough to fit the hardware onto.
2x Cable retention glands ((PLASTIC!)).
2 lengths of heat resistant 3 core elecrtical cable, 1 long enough to reach the power outlet from the controller, and one long enough to reach the fan from the controller.
Some stripped inner wires from the cable.
4x Terminal crimp connectors ((optional but tidier))
4x`Small nuts and bolts to fit hardware onto box.
1x Eye bolt and nut.
1x Mains plug.
The tools you will need are
1 set of wire strippers.
1x Drill with small bit to match bolts.
1x small flathead screwdriver.
1x Medium Crosshead screwdriver.
1x Pliers.
The 1st job that needs to be done, is to mark out the positions for the speedo and stat on the box with a marker pen, marking around them, and also marking the fixing points where holes need to be drilled.
Once it is all marked up you can drill the holes required to feed the wiring to the hardware from inside the box. I made a single hole for the wires to the speedo and a longer slit for the thermostat wires.

After these holes are made and the edges smoothed off you can fix the thermostat and surface mounting box onto the wiring box.

Now the wiring begins.

The exact wiring differs with different thermostats, but for this danfoss RMT230 ive used it is as follows
Power cord connections.
Live to thermostat terminal 1.
Neutral to thermostat terminal 4.
Earth to strip connector.

Fan cord connections.
Live to Speedo L1
Neutral to thermostat terminal 4

Interior connections.
1 length of brown(live) from thermostat terminal 3 to speedo L1
1 length of brown(live) from thermostat terminal 1 to speedo C
I have a diagram but its in the wrong format to put it up(apparently) so ill have to copy one out for here later.

Now this wiring is comlete, you are`almost finished, you just need to screw the speedo down on to the surface mounting box, and put the thermostat cover and knob back on.

Now you should hook it up to a fan and test it before it goes into your growroom


And mine works a treat. The easiest way to test it is to turn it on, lower the speed, and then turn the thermostat down to just lower than the temperature of the room you are in, it should click the stat on and the fan flip into full power.
All thats left is to mark the minimum and maximum points on the speed control and its ready to install.
This is a great bit of kit and has cost me 30 pounds to make. To buy one of these in the growshops is around 100 pounds although granted that one is a bit prettier, but for less than 1/3rd of the price who cares about pretty.
I am only using it for extraction control with passive intakes, but if you are using a dual fan setup, you can control the speed of both with this if the fans total power doesnt go over 250 watts, but it would be better to add a second speed control to control a second fan!
I plan to update this thread as i modify/expand this, eventually into a complete enviromental controller. The 1st modification will be to swap the mechanical thermostat for a digital programmable one. with a programmable stat the enviroment can be even more finely tuned with several time zones through the day, with the temperature being able to be set different at different times. this would allow the setting of a lower temperature at night than in the day and be more like the natural world!
Another good addition would be a Humidistat also wired in to override the speed controller when the humidity reaches a preset level. This is what i am looking into right now, trying to find out if it will work.
So, without further ado, here it is....

complete with note to remind me it buzzes less if the fan is switched on at full speed and the speed turned down after switch on instead of switching on at a low speed-it really makes a lot of difference for some reason.
Well that is all done, I hope to see some of these appearing around here soon.
I cant take credit for this design, the origional was done by "Fazered" at UKCultivator some time ago. That origional design had the speedo and stat mounted seperately on lengths of cable connecting in a small junction box. I have just changed it up a bit.
I must also say a very big thank you to OT1 over at UK420, for being super helpful and translating the wiring of the fazfan into a proper wiring diagram with the right wiring colours, and giving me the correct wiring for this thermostat, which is not the one used the origional. So many thanks to OT1, and much respect to Fazered for the inspiration.
right, that'll just about do it I think, Time to go now, i wanna go and fit my new gizmo into my room....
hope you all like my little contribution.
Catch you all later,
Be lucky now
{EDIT} Here is the wiring diagram that i finally remembered to add..

Very cool this needs to be added to DIY link o rama............

Glad you like it.., I have mentioned it in the link o rama thread

Bump,...
just keeping this on the front page for folks to see.......

fuckin a, nice post harry.

kick ass

Great work!!! Does this thing have an option, to run your fan @ 130%


Be good!!

thanks for the props ppl.
....I wouldnt have thought so treehuggers lol-thats explosion territory i think hehe.

Nice one harry, very clever m8 just what I need for my new grow room.


Heath

H my friend, how the Devil r u, and am i seeing things, has the injustice been put right?? lol, you know what im talking bout mate.....
Gld you like it mate.....its just the same as the ones at UK420, except i mounted mone to box propely with cable glands instead of having the little junction box and wires dangling straight outta everything....if im making prima/ Klimavator i might as well make it look like it(sort of), Just wait til i do the big one, my total growroom controller unit, gonna have the lighting, ventilation, heating,feeding and whatever else all controlled from one board/box....
Well best be off.
Nice to see u here,
Be lucky

how is the big one comin

hi, right now its still jjust being thought through and im decided exactly what i want it do control, and how to go about it, for instance i had planned adding a humidistat onto this controller, but actually making the fan run faster in the dark period when the RH rises would makes it colder, and thus raise the RH even more, so now im thinking about making the humidistat on a seperate thing(to be incorporated into the total controller when everyting is sussed), and to be able to switch on a dehumidifier, which is one of the things ill be adding to my euipment shortly, found some great ones for not much money. As for controlling feeding pumps on the total controller, im not sure how yet, as the plug in timers ive come across are unreliable, i am thinkig about just getting a cyclestat like one of the ecotechnics recycling feed timers, the minute one. Now that could be used on the total, but just plugged into a power strip like normal so wouldnt be integrated really......
As you can tell, its far from being anywhere near ready to put together lol....
be lucky

nice

Nice one, people need to know!!!

Keep up the most excellent work!!!

GrowDoc

Very Nice Harry, alot of people will find this very handy
I was speaking to a bloke in the u.k at OverGrow back in the day, and he was designer a complete automated system, controlled from his p.c at work. He'd already set-up his feed units, to measure e.c and top up with either fert of plain water dependant on the electronic e.c reading it was giving - Clever stuff. Lost contact with him when O.G went down. It's defo something I'd look into because sometime's I just aint near the garden to do work and me girls suffer!

Anyone in the u.k planning to get materials for this type of set-up, I'm telling you to go to screwfixdirect(u.k) We sometime's buy bits n bobs off 'em at work, they're cheap as chips and they'll deliver to your doorstep the next day.

All The Best and NiceOne again Harry
Guv'nah

ey up, lol screwfix....soon as i know theres a new ctalogue out im straight on the phone..... I just got some ofthat flat pvc ducting to send the air outside...plastic airbricks and a couple of 90 degree bends for a light trap... u know...
Screwfix rock and id have ordered the thermostat that i made this with from them in the 1st place, but at thetime they didnt have the honeywell one and greenfingers website did so i ordered it there, and when it came it was this danfoss...cost a 5er more too lol but never mind.... id recommend screwfix..a homegrower can get almost everything for a grow there...250 watt lowbays, gutters for hydro, pipes to build rooms, ventilation...
My complete growroom automation is back on the move again now...im looking at some components.... like some reptile tank equipment-take them apart for the compnents and put my own thing together in one neat box.
I have to say though ive found a great fan controller that i might just buy... its at hydro hobby, called the "Trade air 3" its a pulse potential cooling thermostat. Only one knob, dont need to bother setting an idling speed, you just set your temps and it fires up, then drops to 30%, if the temp is above your setting it rises a little bit, if it needs more speed it rises a bit more til the temp is right, then when ur lights go off and the temps starts dropping rapidly it slows down again.... Thats 89 pounds.... but i also really like the "Secret Garden temperature controller", which is at pro grow, its the bollocks mate, 189 quid, its got a fan circuit and a heating circuit, 1000 and 2000 watts per cicuit respectively, independant of each other, min max settings and an idling speed controller, really well thought out..actually all the secret garden stuff seems really good...im definately getting the hydroponic feed timer from the secret garen range...its got a grasslin on it but its got a cycle knob also with 20 second, 40 second, and 1,2,4 and 8 minute settings..so it can do tiny feeds up to feeding constantly-either 24/7 or whatever time of day.
Check em out.
in the meantime...ive been looking at the Nutriculture TMU, you know the old timer modifying units that you piggy back off a segmental 15 minute timer to get individual minutes or seconds..well im thinking maybe i could take one of those apart-remove the plug thing so basically hard wire it inside plastic box.....
anyway this is a looooong fucking ramble mate lol.
It does work well this speed controller, does the job, but obviously you have to keep adjustuingthe idling speed every few days to account for changes in temps outside if you want to keep steady temperature-thats why the pulse potential stat is appealing, other than the fact that its 100 quid less than the secret garden one lol.... this homemade one will be going in my vegging garden if i buy one of the shop bpught ones ive mentioned(and if i buy i may spring for the SG in the end..)
for anyone who wants simple On/Off contol with a thermostat, google "lucky reptile thermo control PRO2" its a terrarium digital thermostat that can be used for heating or cooling,has a timed circuit with 2 on/offs per day and can handle 1200 watts, you could run automatic feeds or up to a 250 watt(no bigger coz of inductive load) light on the timer circuit and the thermostat turning the fan on and off when the temp reaches a set level. It also has a night temp drop facility too, theres also a cheaper version without pro in the name that can only be used for heating and doesnt have night temp drop...im gonna get one of these to control my feed times and the tank heater when winter comes around.... Some really good stuff among terrarium equipment... just check out Habistat stuff.
Anyway this is even loooonger and more rambling now lol...
so im off before i give u all a migraine trying to read with my lack of puntuation or paragraphs..
Be lucky ppl

WOW, ^^^WTF was i on there lol......
Stay tuned ppl, the newest incarnation of my speed controller will be posted up in a few weeks.... with remote probe thermostat and 2 speed controls for in and out fans off varying sizes to match up the airflow correctly.
the complete room controller is going to be built after this new improved ventilation controller., and the features I hope to include on it are,,

Timed circuit capable of handling at least 2x 600 watt lights(but could be modified by someone else with a larger relay to handle more. + 500 watts of auxillary equipment to be switched on/off with the lights,ie aircooling and circulating fans, uv bug killers.
Timed circuit using digital or preferably cycle timer for accurate feeding of all hydroponic applications.
Thermostatically controlled ventilation circuit.
Thermostatically controlled heating circuit.
Non timed circuit with spare outlets up to 1000 watts.
and if possibe a hygroststically controlled circuit switchable between humidifying and dehumidifying functions.

Other possiblities that i might add is a second thermostatic heating circuit using a pulseproportional stat attached to a photosensor, to controll temperatures in heated propagators or even the heated mats under rockwool slab or soil grows which are used often in europe....
Feel free to make suggestions....

very killer cant wait.............

few weeks.....
i may not bother using this for lighting-safety reasons cant have all that running from one plug