View Full Version : My summer project
Well my temperature dependent fan speed controller is now well on its way (well the PCB anyway) final bits arriving tomorrow to complete the circuit board assembly...
Second stage now is to write the controller software for it, and is this which is the tricky part, Veeeeeeeery complicated stuff.
As a recap as to what the hell i'm going on about...
For a while now... infact since my first bonafide overclock on the first computer i ever bought (not given), my Athlon classic 550 (750 core) OC'd to 916 (about 3 years ago now), I’ve wanted to quieten my machine down as far as possible without making the machine lockup through overheating.
Early plans were simply a bay bus set-up, but as I learnt more, my plans got more ambitious... fan speed control using a microcontroller... adding digital thermometers for automatic control... adding a screen to show temperatures...
Now my plans stand at:
Hardware:
4 line, 16 charcter backlit LCD screen
Multiple temperature sensors
7 channel fan outputs (molex connectors) upto 5A per channel (well that’s what the MOSFETs can take - but I doubt my PCB can!)
Real-time clock
Completely controllable via serial link or independently by external buttons
Prospective software aspects:
Up to 32 temperature sensors
8 fan speeds
Completely user definable combinational control schemes
Real-time clock to enable different schemes during the day, i.e. silent mode at night.
All settable by external buttons and on screen menu system (prolly awkward to use) or via a nice windows GUI (MMMMmmmm)
Logable temps to HDD etc.
Possibility of windows software doing stuff with system (such as processor identification, internal diode temp, shutdown, alarm, starting idling task etc - if I can be arsed to find out how and if its not too tricky)
Possibility of automatic 'tuning' of control scheme to improve cooling (bit iffy)
Other REALLY cool stuff as I think of it :D
AVALIBLE:
August... 2013... prolly
Just gotta think of a name for it... :D
sounds very nice.
regarding the identification of procesors, chipsets and stuff, try emails people who have already written software to do that, i would think most would be happy to give some help.
as for the rest, no idea, but it sounds pretty bloody kewl :D
toodles :xsofa:
Originally posted by MrP
sounds very nice.
regarding the identification of procesors, chipsets and stuff, try emails people who have already written software to do that, i would think most would be happy to give some help.
as for the rest, no idea, but it sounds pretty bloody kewl :D
toodles :xsofa:
I'll be writing the windows software in delphi (most likly, but could try C++) which i have already found some freewear plugins which can do the identification stuff - it's the starting and stopping idling tasks which i think will be the difficult bit.
dicki
07-02-2002, 06:35 PM
well like i said before i'll offer any help i can. i can program in c and delphi, embedded and pc software and i can weild a soldering iron fairly well.
on top of that i have pcb layout and manufacturing stuff at work :) let me know if i can help
dicki
Here the prototype board made up (less a few connectors - didn't have enough in stock)
Already i've found numerous mistakes and thought of a few improvments...
At the top is the ICD (in circuit debugger), below that is the LCD screen (obviosly), and to the right of that is the actual controller.
Alon the top are the 7 PWM channels, the ICD interface (which should be a socket, but i put the wrong shape down on the PCB so the connector wouldn't fit :rolleyes:. then theres the Serial interface and the power in.
below the 7 channels is a PIC16F84 which does all the PWMing, the big chip in the middle does all the work (PIC16F877) and the chunky chip over to the right is the non-volitile ram and real time clock.
me likes alot.
would look really nice all packaged into a 5 1/4" case with the LCD on the front (and say a couple of USB ports) and then all this luverly fan monitoring what ever going on in the background
hows the software comming on for it???
toodles :xsofa:
It is indeed sized to fit into a 5 1/4" bay, but i'm woorking on a funky meathod for that. The LCD is too big to fit into a single bay, so my idea is for the screen to slide out and sort of flip down to reveal it's self. When closed the bay would reveal nothing of whats behind, kind of a stealth type thing. Only problem is i have no way of making such a device as i have no machining tools - so that will have to wait. in the mean time i'll have it attractivly flapping around hanging out the ffront of the case :)
Software writing will comence next week when i'm back at my house and at my machine (i'm home with my parients at the moment)
nitan
07-08-2002, 11:28 AM
If you wanna do some real hardcore embedded stuff then gimme a shout i can get my father to lend a hand..he is always bored at work...(he does embedded stuff on scopes and stuff for Gould-Nicolet).....hmm if only there was a dowload thing (matrix styleeee) from him to me!!:D:D:D:D...also i am still a member of uni therefore can use the workshop...if u need any machining work done gimme a holler and i can get into Chris's workshop and get it done....:)
nitan:)
Wee bit of an update, cot the communications with the LCD screen working and the buttons... still a lot to do...
close up on the screen :)
mdzcpa
07-28-2002, 09:41 AM
Cool:D
dicki
07-28-2002, 04:53 PM
looking good shep
WesM63
07-29-2002, 10:24 AM
That's cool Shep. Keep up the good work.
Well i did have a huge explanation on what i've done, but something buggered up and i lost all the text i wrote and i'm very not happy :mad:
anyway new board revision in progress, much better way of controling the fan speed (including three speed sensing ports and voltage monitoring on all channels)
tripodal
08-20-2002, 10:28 PM
great work!
what amperage will the circut handle?
The coils i'm planning on using can only handle 1A (so maybe 1.5A :) ) I could use bigger but they are just that, BIG and with all those components i'm not even sure they'll fit on!
Player0
08-21-2002, 02:40 PM
So you will only beable to handle 1-2amps worth of fans? Is that enough power for all of them?
That's per channel, so you'd be able to have 2 big fans on each of the 8 channels if you so desired (YS-tech rate their 120mm fans at 0.7A so maybe able to cope with that).
(mind you i sincrely doubt the PCB it self could cope with much more then about 10A!)
Player0
08-21-2002, 03:24 PM
Oh...okay per channel makes alot more sense :)
Wow thats some pretty nice work though. Puts my new fan controller to shame hehe :)
actually i've been reconsidering the speed sensing, due to the way the MOSFETs opperate, translating the output of the fan to a usable signal may require more electronics then i can be bothered to do.
Anyone know much about MOSFETS? I have a few Q's
tripodal
08-21-2002, 04:05 PM
sorry no help here, good work by the way. perhaps you can make it possible to configure an out put... (in either software or hardware) to power relays....if desired. for larger fans, h20 pumps, etc.
Player0
08-21-2002, 04:13 PM
I know a good bit about transistors. Whats your question?
I'm not going into switching mains supply voltage, but high current 12V switching would be no problem.
The only reason i'm restricted to 1A is the inductor coils required to smooth the voltage to the fans - the MOSFETs controling them are rated upto 5A continuos current - to use even bigger ones would be no problem even upto 30A continuos... something todo with the three spare pins at least.
One thing with switching large currents is that you don't want to do it too often, as you can prolly imagine. these would be limited to simple on/off and not any kind of high freq PWM.
Originally posted by Player0
I know a good bit about transistors. Whats your question?
The question is about p-channel MOSFETS, inorder to make used of speed sensing...
Now with P-channels you attach the drain to +12V, and the source to one side of the fan, and GND to other side of the fan.
Now my circurty runs off 5V, so into the gate ideally i'd just bung the 5V signal, but that prolly won't work with most FETS it'll just stay on, but are there any FETs where i wouldn't need any level translation upto 12V?
Player0
08-21-2002, 04:41 PM
Why are you using coils to filter the fan power? The fans *are* coils, they will naturally filter out any sort of power fluctuations, high-frequency spikes that the mosfets generate. I say ditch the coils. Use a small filter cap though.
Save room for cooling those mosfets too. Do they get warm at all? :)
Okay so you got p-channel fets...got 5v to gate and want to controll 12v.
I have seen dual-channel mosfets which would probably work like this, but Im not sure how cheap they are or how hard they are to find.
Did some looking, found this: http://www.vishay.com/document/71430/71430.pdf
Maybe something like this?
The only other thing I can think of is just using a drive transistor (probably a bipolar or darlington) with a couple bias resistors and use that to drive the mosfet.
Originally posted by Player0
Why are you using coils to filter the fan power? The fans *are* coils, they will naturally filter out any sort of power fluctuations, high-frequency spikes that the mosfets generate. I say ditch the coils. Use a small filter cap though.
That would be fine, but for the fact the fans are brushless, they have electronics inside to get them to spin, and the electronics dont take to kindly to unsmooth DC levels.
Maxim have a nice article on the matter...
http://www.maxim-ic.com/tarticle/view_article.cfm/article_id/114
Save room for cooling those mosfets too. Do they get warm at all? :)
No they don't actually, which is a very good thing, barely get warm in infact, unless you use them in linear regulation mode, again this is explained in the article. It's when your switching large currents (10A+) at high frequencies (20KHz+) that they start getting toasty
Okay so you got p-channel fets...got 5v to gate and want to controll 12v.
I have seen dual-channel mosfets which would probably work like this, but Im not sure how cheap they are or how hard they are to find.
Did some looking, found this: http://www.vishay.com/document/71430/71430.pdf
Maybe something like this?
The only other thing I can think of is just using a drive transistor (probably a bipolar or darlington) with a couple bias resistors and use that to drive the mosfet.
I'll take a look at that, thanks :)
had a look at that linnk, what you have there is simply two fets in a single package.
I think i'd have to go down the transitor route, as you say, to get the levels i require, just adds that much more complication... another 8 transistors and 16 resistors :rolleyes:
Thanks for the help :)
electronics isnt my thing,but surley if i fan has a RPM sensor on it, all you have to do is connect a sensor or something to that wire to count the RPMs??
or am i missing something?
toodles
Originally posted by MrP
electronics isnt my thing,but surley if i fan has a RPM sensor on it, all you have to do is connect a sensor or something to that wire to count the RPMs??
or am i missing something?
toodles
something is indeed missing.
now i could explain (and i will if you like), but i can't be arsed.
basically it would require a lot electronics to translate the output from the fan to something usable by the microcontroller.
LOL thought i might be.
ignore me, i go away eventually!!
toodles :xsofa:
Me again :D
Progressing well, got some more (Very bad quality) piccys for y'all.
Hears a Piccy of the Clock, which is now fully working:
http://mysite.freeserve.com/meakin673/Time.jpg
then we have the temp sensors menu, where you can search for devices:
http://mysite.freeserve.com/meakin673/search.jpg
then you get a list of the devices found, the little black, transistor looking things are the 12 temp sensors i have. On screen you can see the device number/total devices on the 2nd line, the device serial number on the 3rd, and the device type on the fourth:
http://mysite.freeserve.com/meakin673/precision.jpg
http://mysite.freeserve.com/meakin673/standard.jpg
http://mysite.freeserve.com/meakin673/econo.jpg
Next on the menu is where they the temperature it shown.
http://mysite.freeserve.com/meakin673/showtemp.jpg
Similar to the device search list you can cycle though each device. On the 3rd line is the contents of the device's 'scratch pad' the first two bytes (4 digits) of which give the temperature... which is then formatted to show in deg C on the bottom line:
http://mysite.freeserve.com/meakin673/temp1.jpg
http://mysite.freeserve.com/meakin673/temp9.jpg
http://mysite.freeserve.com/meakin673/temp12.jpg
http://mysite.freeserve.com/meakin673/tempfinger.jpg
dicki
09-16-2002, 05:01 PM
wow it's storming along mate, do you have the fan controllers working yet? i really need a quiet computer :)
Greywolf
09-16-2002, 10:36 PM
Awesome work...if you could be bothered to you could sell them for a mint.
Even if you got the components in bulk and sold them with some well designed plans would make a nice sideline.
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