Computer Temperature Monitor Project

Hey all! Just wanted to say you have a great Community here!

This is my first posting, so I would appreciate any suggestions or help here from the forum community.

I have a Project that I am working on for my Senior Design class for college, it is a device similar to the DigiDoc device, in that it measures temperatures and also controls fan speeds. I would like your opinions, and suggestions for functions that I would be able to implement.

Here is a listing of what I have thought up so far for this device to do:
1. Monitor 8+ temperatures (10K Thermistors)
2. Monitor Fan RPM's
3. Control Fan Speeds (PWM? Linear control?)
4. Connect to the computer through USB
5. Display Different Screens on an LCD
6. Push Buttons on the Front panel to switch between information quickly
7. Maybe interface with the Motherboard using the SMBus feature
8. Incorporate I/R devices to possibly enable a Remote PC Control
9. Software Utility on Computer allowing for Customized LCD screens/temperature monitoring/other features
10. Progressive Speed changing on Fans - As temp goes up fan speed goes up
11. PC Shutdown if temperatures increase past cooling capacity
12. Watercooling ideas?

Any Other Ideas? I will post more details when I get things figured out.

There are many features here. I know you guys will come up with other good ideas, and I hope to find the Hardware that will be beefy enough even for you guys. Thanks in advance!

Lazer

Why redo the DigitalDoc?

I would produce 2 good measurements. CPU temp and case temp. Both are extremely hard to do well and accuracy costs. I would pay top dollar (well within reason) for this capability. Do a cost-performance study first.

In the end, provide accuracy info and validate them.

Accuracy, check thanks!

Another thing, the digidoc only supports turning the fans on and off, not a speed control for many fans. That is what I am hoping to do, Independent controls for each of the fans. I know my case at the moment is very loud, and I would like to have something that would automatically change speeds based on how much heat is being produced.

~Nate

The problem is that you can't effectively balance the system dynamically as you envision. Time constants of the temperature monitors and fans are much faster than the case volume and it'll take a significant amount of experimenting to do it. I started down that road and decided it is much easier to establish a fixed case flow (yup one fan setting only, on and off works just fine and add voltage control that you set once) and let the case temperature float based on cpu load. Only a couple degrees change between idle and full load.

I am looking for a similar device. I have a DigitalDoc5 and I like its functions. Having direct readout of 8 remote temps on a fixed LCD is great.

But, now lets take it to the next level (or two) and provide a hw/sw solution that allows for the monitoring of all the sensors built into the MB and disk drives, plus several remote sensors and allows for the user definable, progressive RPM control of each fan based on any of the monitored temps.

Oh, and also have user definable alarm points for each temp sensor or fan RPM sensor.

I know this is asking a lot, but this is possible. It would be like having a DigitalDoc and Mother Board Monitor combined on steriods.

Maybe this capability is already available. If anyone knows of a solution, please let me know.

Greg Jones

Well, you could easily take care of the fan control aspect with potentiometers. It would be Power(coming from the LCD thing that you're building) -> Potentiometer -> Fan, and then the yellow wire would plug back into the LCD thing, which would measure the RPM's.

Okay, basically, I have no idea, whatsoever, of what i'm talking about. What I posted above is probably right, but this isn't really one of my areas of expertise.

If this thread doesn't turn up too many result, head over to the Alternative Modding section. They'll be able to tell you everything you need to know about getting the LCD up and running.

Good Luck, and WELCOME TO THE FORUMS

If you actually do end up creating something like you have been describing, I'm sure a lot of people on these forums will be interested in buying one, including myself.

-CPFitz-

Glad to have another! WELCOME TO THE BOARDS!!!!

Planning is rough

There are lots of things that I want to do with this project, and I doubt that I will be able to them all in the first revision. What I am looking at right now is trying to figure out a microprocessor that will enable all the output that I have to deal with. any helps?

another question I have is where is a good place to get thermistor probes from, like the flat kind you get with the DigiDoc? I am kinda tight on funds so the cheaper the better.

Thanks in advance again guys, you have made me happier that I have some help in this project!

Welcome to the forums! I went through a phase of planning a fanbus about a year ago. It can be a lot of fun.

I can tell you that generally speaking, PWM is not compatible with the way the fan's RPMs are read. So, you'll want to vary the positive voltage of the fans if you want to do speed control.



The RPM wire varies between a high voltage (the supplied + voltage) and a low voltage (the attached ground) twice per revolution (four times per revolution on some fans). Since PWM turns the + voltage on and off rapidly, the fan RPM signal will be interrupted many times per cycle, although impedence may mitigate that effect when the speed is closer to the fan's actual rated speed.

One feature that might be nice is a minimum voltage setting for each fan channel. On my controller, I implemented it in hardware via a combination of zener and crystal diodes, but as far as I can tell, you have much more electrical circuit design prowress.

Hmm, you might also want to consider 100k thermistors. I seem to remember that each type (e.g., 10k, 100k) is better at different temperature ranges. I've gotten a good number of components (including NTC thermistors) from www.jameco.com, but I don't think I've ever found particularly thin thermistors like you're talking about.

Good luck, and keep us posted! -- Paul

I don't understand why, if it's partially a software solution, that you need a separate unit to control it. For USB control, do you mean it will output commands through onboard USB headers to the relays that control the fans and input the sensor info the same way?

I just don't see where USB plays a part in all this.

I take it the USB is to update thresholds and set values.
That is the hateful thing to do through the facia buttons.
I also take it he will also be writing a tool similar to MBM's
dashboard for when the data displayed is too complex for a lcd.
One wish - a graph mapping processor load against fan speed against time (or i'll do one myself).
What can be implimented is a Three Term Control - predictive
measurement of CPU load and variation of fan speed to keep the
CPU at constant temperature.

Hmm, that's an interesting idea. If the the algorithm had basic C/W and thermal output data incorporated, it could probably make at least a good short-term projection of the fan speed necessary to maintain the const. temp. It sounds like you have some very good experience with this, though, so I'll look forward to following your posts hre! -- Paul

I doubt that this guy is still taking advice, considering that he posted on Jan. 5th. But, it would be nice to hear from him with some updates on how the project is going .

D'oh! Note to self: read the dates.

And I agree -- I'd really like to see the results! -- Paul

Read the dates?

yeah true I haven't gotten any help in quite a while...I was starting to lose hope in this thread for gaining some wisdom, btu I was suprised and happy to know that you guys had not let me down.

I am still working on this project, and I have a few questions for you guys to ponder:

1. is there a way to measure hard drive temps directly? do they have some sort of temperature sensor built in?

2. what are your thoughts on sending PWM thru a capacitor to smooth out the peaks and send more or less a constant varying voltage?

3. what kind of general purpose Outputs or inputs can anyone see using? (like for cold cathodes and other lights and such?


you guys may take a while but you still pique my interest, thanks for the info!

Make this:
http://forum.oc-forums.com/vb/showthread.php?threadid=175629&highlight=probe

Re: Read the dates?

Lazer_wolf said:

I am still working on this project, and I have a few questions for you guys to ponder:

1. is there a way to measure hard drive temps directly? do they have some sort of temperature sensor built in?

2. what are your thoughts on sending PWM thru a capacitor to smooth out the peaks and send more or less a constant varying voltage?

3. what kind of general purpose Outputs or inputs can anyone see using? (like for cold cathodes and other lights and such?

Click to expand...

1. Yes, all modern hard drives have built in temperature sensors. They use a S.M.A.R.T. standard (Self-Monitoring Analysis Reporting Technology). I wish I could tell you more, but this is all I really know about this.

2. It sounds like a good idea. I think that you would want to put a resistor in series with a parallel capacitor. Otherwise, the capacitor would discharge too quickly, changing the output to always be high, thus negating the entire pulse width modulator. But if a resistor was there, then it wouldn't actually level out the output........hmmmmm

3. What I don't like about temp controlled fans is that the temperature-fanspeed settings are factory locked. I think that these should be adjustable by the user. For example, I should be able to set my CPU fan to spin at 100% when the processor reaches 50C and not at 60C, as with the default setting.

Just a quick question for all you electrical type people. What would happen if I took PWM and instead of varying the voltage from 0-12 volts across the fan, if I varied it from, say, 3-12 volts. Do you think that the RPM sensor on the fan would still function properly? I know its output would vary from 3-12 V, but would it still be functional? thanks all!

Hmm, I've generally observed that RPM monitoring drops off at around 6-7V, but it's going to vary with the motherboard.



@DarkJediSleikas:
Are you sure that all modern hard drives have temp monitoring? Although my WD has SMART, MBM didn't identify any temp monitoring on it. (Nor did speedfan.)

-- Paul

hmm well I am not going to use the motherboard sensors to detect rpm, going to have one I design to read the pulses and calculate the rpm. good point to watch for though, thanks

~Nate