Matrix Orbital Corp

i remeber cold candian winters, working nights in a truck wash with icicles forming on my nose, not feeling my feet and hands for 10 hours at a time. thank god i live in cali now. the winters here are sweater weather.

the car starter thing is cool. i have no idea how you would do it tho

Hi their this is my first post... How about we post the code, and some diagrams for our ideas, too? That way we could all benifit from the ideas, and prove that we put some effort into it?
Just an idea.

On 2001-09-06 08:50, mbeher wrote:
Hi their this is my first post... How about we post the code, and some diagrams for our ideas, too? That way we could all benifit from the ideas, and prove that we put some effort into it?
Just an idea.

That would be great! Sharing ideas is what this is all about!

I'm building a stereo component that runs Linux. Is that cool enough? I've got a GLC24064EL to mount in the front. The system is a 1GHz Athlon on a gigabyte microatx board. The case is a 17" x 10" x 4" steel box that I am currently cutting holes in

WOW... impresive... can't wait for the pics!

my plans:
black 16" case (painted this sunday )
window mod with ~20 leds behind it (christmas tree!), clear-orange emergency light cover on top (covering previous 150mm blowhole for 350cfm fan) with 110volt ~20 watt light.
and for the lcd part:
4 line x 20 character lcd in the front, attach keypad to control mp3 player (winamp most likely).
The comp will have no keyboard, mouse, or monitor, just a spearer system for the sound, and the keypad to control winamp.

any suggestions are welcome

Well, I think it might be time

Lets get some ideas going!!!!

Hrm, my idea is to use the GPOs in PWM mode to do fan speed control. I've seen some schemes that use two GPOs to get dual speeds, but I'm talking continuous speed control purely achieved in software.

Now mind you, I fling a bit of code from time to time, but I'm not really a Windoze kind of guy, so I don't know if the idea is impractical as stated. However, it does seem to me that there's the alternate technique of using the GPOs as a n-bit digital word fed to a D/A converter that modulated fan speeds with analog voltage control.

I've seen Psylence's LCD dingus that uses a PIC, but I figure the market would be better for something that could work out of the box (sans additional components), so plan A is as stated above.

I had thought of using PWM on the GPOs but wasn't sure if they were capable of continuously switching at a high enough frequency, (30-60 Hz).

I would be very interested in how you get on.

You could use a single bit dac and use the other gpos to multiplex/address multiple fans etc. (more than just the number of GPOs)

I will have to wait until my VFD arrives before I can experiment

A single bit DAC IS PWM. A plan (involving extra parts) might be to use the GPOs as a communications interface to serially controlled DACs, 6 GPOs should be able to control 4 SPI interface DACs.

If you are willing to constantly send commands, you can get PWM on a GPO at up to about 70 or 80 hz, if I am not mistaken. We have done this with a backlight, changing the brightness of it by turning it on and off very fast, the LCD is capable of doing this.



_________________
Henry J.
Technical Support
Matrix Orbital


<font size=-1>[ This Message was edited by: Henry on 2001-11-30 15:50 ]</font>

OK, let me get this straight, you're saying that I can modulate the GPO by sending on/off messages serially....

Of course, addon hardware is not something most peeps want to deal with, so this could be a powerful toy, even if you couldn't continuously vary the pulse width. MO LCD + software wizardry = fan controller from H3LL.

Hmmm, maybe it's time to bust out the 'scope....

ooh, one more thing, Henry, could I have a look at the backlight modulation code you did? pretty please?

I'll answer that. No.

The code is (was) written for a 8051 microcontroller and communicated over I2C. There was however, some Linux code that one of the LCDproc guys wrote back in about 1997. He is not around anymore and I don't believe it made it's way into LCDproc, so that's probably a dead end.

Now that I think about it, there is no real sraight forward way of getting at that sort of time resolution in Windows.

Let's say you want 40Hz (Capacitors before bandwidth!). Lets also say that you want 16 levels of control. So, you will need to have about 1.6ms resolution. I know of no way to do better than 50ms resolution in Windows, but I am very sure that it is possible.

At that rate you would be sending 80 commands per second (240 bytes), so at 19200 baud, that amounts to 12.5% of the available bandwidth. Since turning on and off GPOs uses very little processor overhead, I think it is reasonable to assume that it could keep up to an almost stuffed "pipe". Since there are 6 GPOs, that would be only 75% of the available bandwidth at 19200. I would have to try it, but I'd say it's worth a shot to make all 6 GPOs into PWM outputs at the same time.

I agree that a software only solution would be the most popular but I have doubts that it would be completely suitable.

Under heavy CPU load timing may become an issue causing irregular fan speed also without some extra hardware the fans would be switched off until the OS and drivers had initialised. Not good if using to contol CPU hsf.

I have been considering using 3 0r 4 gpos as a 8/16 level dac and the remaining two to control a mux/sample hold driver. A pair of OR'ed monostables to give the sample pulse. Only thing is ....extra hardware

As a thought, why not design a new series of display with 256 level, 0-12V outputs?




<font size=-1>[ This Message was edited by: Macro on 2001-11-30 16:59 ]</font>

my idea: combine a reobus and a lcd, with some stepmotor or something so that you can control the turning buttons with software, and if you change the state of the buttons the software has to recognize that and has to send a status update or something to the lcd. Will be hard, but, everything's possible...