Comm/Serial Port Temperature Inputs

[VB Junkie]

Hello,

I am currently writing a very complicated program which very basically reads temperatures from inside of the computer, determines if they are acceptable or not, and then adjusts the voltage to four different fans inside of the computer case to counter any increase in temperature.

I have the program almost totally done, all that I have left to figure out is how to read temperatures, preferably from the serial port. I require at least four separate probes, and for them to be able to be read via the serial port. I originally had thought of using the game port (as I have used the game port in previous stepper-motor programs and such), however due to the nature of the program and the fact that it is specifically made for server computers, the usage of a game port would be heavily restrictive.

I would appreciate ANY help that you would be able to give me, as I’m really stuck on this matter! I’ve spent into the hundreds of hours on this program, and it is just fabulous, and I would be ecstatic if I was able to get it fully done soon.

Thanks a lot.

~ David ~

[DevGrp]

Sounds interesting. Can we see a demo? Sorry I cant help though.

[VB Junkie]

Id love to show you guys a working demo of it, but i wanna get the sensors working all corectly before i begin beta release.

I got bored, and actually added SO many features to it that you can literally change all the graphics and colors of EVERYTHING in regards to the main floater. The main window pretty much has four "Spedo/Tacco" looking graphical displays, and they move 180deg depending on the temps and shows all the info and what not. it looks VERY cool and very customisable. (Even change transparencies under XP!!! )

But guys, untill i get the hardware working, imma hold back the beta release. I miight later on take some screen shots of her in operation for you guys tho!

and plz, if anybody knows n e thing about temp probes and serial/comm ports.. HELP ME PLZ!!!!

~ Dave ~

[Jared]

Well, I actually have worked on projects similiar to the one you are doing. I have a couple of questions:

1). Will your application and the temp probes be on the same PC? Or will they separate, and if so, will you have to have modem access involved?

2). What type of output does the probe output? Is it serial data (more sophisticated probes will actually output ASCII code), or is it the style of a thermocouple, which will only output a resistance in ohms?

The only issue that will be a challenge to tackle is the fact that you have FOUR probes. I can see 2 ways of going about this, and it depends on the data output of the probes:

1). Use a time division method of getting data from the probes. If you are using programmable probes, have each probe report data every 'n' number of seconds, and offset them by n/4, to insure that they don't report at the same time. (I wouldn't recommend this approach, though, it gets tricky with getting the timing correct). This would kind of be a caveman's version of Ethernet, but using timing to insure no collisions would occurr.

2). If you are using a thermocouple temp probe: These will constantly report a resistance in ohms depending on the temperature. You can interface many of these probes to a microcontroller (such as a PIC, which are easily programmed in a version of BASIC, ). The code in the PIC will grab the values, and send them serially to the COM port on the PC in which your app is running. I recommend this method, the PIC and its programming can be figured out in an evening or two, and you have complete control of how to send your data to the serial port, and then you code your app to do whatever with the data! Control is a wonderful thing.

Anyway, once I know a little more about your unique case, I can give you more specific info.

Sounds like a fun project......

Another wonderful thing about vb.net,,,,,,,,, (as opposed to VB6), the standard (cheapy version) of vb.net supports serial communications!, and with vb6 standard, no such luck. So for about a hundred bucks, you can have a COM port enabled app!


-Jared.

[VB Junkie]

Hia Jared,

Thank you for your interest and input. And i shall now answer your questions!

1). Yes, the temp probes will be connected to the same computer as the controller and the fans. It's made as pretty much a very customisable Digi-Doc (if you know what that is).

2). I don’t have a clue about the temperature input, infact the temperature input is about the only thing i have left to do! I've left it to the very end, however my code is all prepared for a temperature input to trigger procedures.

Hmmn... i may just have to invest in a copy of .net! right now i only have 6, however I am using the IO.dll library and find it VERY effective in communications to the parallel port.

Once again thanks Jared for your help! It is GREATLY appreciated, and I hope you could help me further in regards to possible solutions (including about this PIT PC).

THANKS!!

~ Dave ~

[Jared]

Okay, so it seems that all you need is the temperature hardware and a way for all your sensors to send serial data to the COM port on your PC.

Here is a start for a very inexpensive temperature sensor:

http://www.jameco.com/Jameco/Products/ProdDS/23755.pdf
Jameco company sells alot of electronic components at okay prices, you should be able to get all the electronics side of the project from there.

Here is the compiler software to program the PIC microcontroller:

http://www.jameco.com/cgi-bin/ncomme...nbr=501&ctgys=

And this is the PIC16F84 microcontroller that I have used:

http://www.jameco.com/cgi-bin/ncomme...nbr=501&ctgys=

That should definately get you started. The PICS are relatively cheap integrated circuits for what you can program them to do. Anyway, let me know if you need anything more.....

-Jared.