What features do you want in a high-spec fan controller?

[LethalCorpse]

G'day all,
I've embarked on a project to build a you-beaut, full-featured, cook-your-dinner-and-screw-your-wife-for-you digital fan controller and monitor. My general goal is to produce a unit which will have up to eight temp sensors, eight speed sensors and eight variable voltage fan power supplies. User interface is, at this stage, going to be via a 2*16 char LCD panel (cheap, readily available) mounted in a 5 1/4" bay, and a set of microswitch buttons that let the user navigate through the screens, adjust settings etc. I want to have the user able to preset target temperatures, fan voltages or target fan RPMs; preset a few different profiles, such as summer and winter or loud and quiet, overclocking and stock etc; calibrate the fans (eg RPMs at max voltage, voltage and RPMS just before dropout, voltage vs rpm curve etc); and select a few different types of monitoring screen, eg one screen with summary speeds of all fans, one with summary voltages of all fans, and one with summary of all temps, as well as a set of detailed screensto display and adjust each fan and temp. At this stage, I'm planning on using the PIC 16f877 or 18f452, they've got plenty of grunt and (more importantly) 40/44 pins each. The code will be difficult, as there's lots of stuff happening at once, but maybe you guys can help me with that. I've already been asking questions about voltage control, you can see the discussions here . I've pretty much decided on PWM controlled voltage regs as the best way to do it - resistance controlled voltage regs put out too much heat, rheostats would be impossible to control digitally and straight pwm to the fans kills the ability to speed sense. Any further comment on this would be welcome.
What I want to know from you lot is, what else do you want to go into it? I'll be posting everything here throughout the process to seek comments and suggestions, and also so everyone else can benefit from the design. Don't try to flog them though, I just might sue
cheers,
-LC

[SaTaN]

will u make the source and plans available when ur finished? sounds awesome...

good luck

[Cnidus]

Thats like EXACTLY what i'm after..... Source and plans would be awesome. I like Opensource projects, makes life so much easier for everyone else, and everyone benifits because designs are constantly becoming better.

[ozzy7750]

i cant think of anything else that anyone could want from a fan controller!!!

just one thing though - make sure that it can be scaled down, I know that if I was to build on/buy one I only have two case fans(rad and case) so would see no point in having so many channels. being able to monitor a lot of temperatures would be very useful though, ram, gpu, psu, rad, nb, hdd's, water etc.

and now i am probably just being annoying, but i have a 4 x 20 LCD, so it would obviously be good if the lcd size could be changed to suit. i dont know a lot about how LCD controllers work (mine is a Hitachi chip, a parallel LCD), but maybe I could rewire it, have my LCD software driving the top two lines, the bottom two driven by your fan controller.

[Cnidus]

yeah i think 4 x 20 LCD support might be improtant for such a feature rich display. It would seem a shame to have such a wealth of information and function, yet have a small lcd displaying it all. Still even if that is the case it will still be an insane little controller, i want one

[SaTaN]

wouldnt it be easier and cheaper to built it around a parallel or serial interface instead of the pic?, that way its all down to software...?

[Symon]

Originally posted by SaTaN
wouldnt it be easier and cheaper to built it around a parallel or serial interface instead of the pic?, that way its all down to software...?

You would still have to design all the I/O interfacing and programming. There wouldn't be much difference between using a PIC and using the PC to do the control. If you use the PC then the software won't start until the machine has booted, so you have a few seconds where you have no fans at all! I think a PIC based design would be easier... not really cheaper though.

I've been thinking about something like this for a while, and I have a small design, but it uses LED displays and no central controller. I'll tidy up the I/O circuitry and post them here for comment.

[Symon]

Originally posted by LethalCorpse
I want to have the user able to preset target temperatures, fan voltages or target fan RPMs; preset a few different profiles, such as summer and winter or loud and quiet, overclocking and stock etc; calibrate the fans (eg RPMs at max voltage, voltage and RPMS just before dropout, voltage vs rpm curve etc

You wouldn't really need a summer/winter setting if you have temperature targets. I don't know much about water cooling, but perhaps you might want to alter the pump speed as well?

[pSYc0de]

would it be able to read the rpm from the wire from the fan?

[Cnidus]

Originally posted by Symon
You wouldn't really need a summer/winter setting if you have temperature targets. I don't know much about water cooling, but perhaps you might want to alter the pump speed as well?

Pumps dont usually have a speed setting, also considering most are 240v devices i dont think it would be practical or safe for most of us to fiddle with 'em too much (ofcoarse a silent mod or whatever does nothing to the actual mtor side of them so thats ok).

[LethalCorpse]

glad to see I've got plenty of interest in this one. First off, yes, all the plans and code will be available (and discussed) here right throughout the development. Standard open source rules apply - make and tweak them to your heart's content, just don't make any money off them. I agree with the 4*20 display, it's a lot of information, and on a 2*16 display the most you get in a summary display is one char to identify each channel and 3 chars to display the value. I just happen to have a bunch of 2*16 panels, and LCDs ain't cheap, so if I can do it that way it makes my life easier. Maybe 4*20 support as a second build? Also, I was thinking of adding software support in a second build - add usb drivers to the pic and plug it into a USB header, so it can talk to a basic monitoring program. That's a good one because it will probably just involve adding a few components and plugs to the PCB for the first build and then a software upgrade will give you PC comms. Or, of course, comms to anything else you wanna make which has USB.
It should be possible to demux the two parallel ports to get two inputs displayed on the 4*20 display. I don't know enough about the LCD drivers yet to give you pointers, but if you read the data sheet you should be able to get it soon enough.
Yes, it will be fully scaleable, so you could remove fans (and their controllers) or temp settings as required. Might be difficult to add more though - the PIC has lots of pins, but they are still limited. It's got 4*8-pin ports, though we might need to lose some of these pins to clocks etc, and I haven't, as yet, seen a lot of multiplexing possibilities for this circuit, as for the PWM it'll need to be constantly talking to each reg or DAC. If anyone has suggestions here let me know.
Symon I'd love to see what you've got. Sounds like it could really help us here.
Psycode, yes, it will definitely be able to read the tacho output. I was initally playing with straight pulse width modulation for the speed adjust, but the problem with this is that if the voltage the fan is getting is a series of pulses rather than static, the pulses you get out on the tacho line will be completely messed up. So I've decided to play with digital-analog converters, PWM based voltage regualtors and op-amps. This will be the most fun part of the circuitry - more on it as I've got time to learn more.
Symon, the idea behind a winter/summer setting is just a collection of presets. You might want to set slightly higher target temps for summer than you do for winter so the noise isn't so loud. I agree, though, the fact that you've got target temps does, for the most part, cover all situations, but I just wanted to make the point that a user might have different setups for different situations, and I plan to design the software so they can save those setups as profiles.
I'll do some more research tonight and post more then. Keep the ideas coming in.
-LC

[LethalCorpse]

It *may* be possible to get this circuit to talk to a 240v pump. There are dimmer switch kits available for jaycar, altronics etc. If you could convince one of those to chose a variable output up to 240\VAC based on a variable input up to 12VDC you'd be on the money. I'm not planning on implementing anything like that at this stage, but if you want to try it in parallel good luck.

[SaTaN]

query about the display....
were u planning on making it a "static" display that had everything on it at once? or something that by hitting a button the pic would change the display,
|=============| |=============|
|fan 1 speed, temp | hit a button and |fan target speed |
|fan 2 speed, temp | it becomes |something else |
|=============| |=============|

(hehe ive always wanted to do some ascii art )

[LethalCorpse]

planning to have a couple of different types of display. One screen with all fan speeds, one with all voltages, one with all temps. Then one screen for each channel showing all the information and allowing for adjustments in target temp, target RPM or manual voltage, fan calibration, fan and temp naming, all that kinda crap. Also probably a screen or two with general configuration stuff, profiles and other assorted malarky.

[Cnidus]

and a set of microswitch buttons that let the user navigate through the screens, adjust settings etc. I want to have the user able to preset target temperatures, fan voltages or target fan RPMs

i think he already answered that one.......