Hello there,

I'm going to hack something together to create some kind of universal load monitor.
That sounds quite universal, so I'm going to make a little more details about this idea/project;

- 25 x 17.5 cm translucent pvc panel
- 2.5 mm LEDs, white, enough to fill the whole board in a grid
- A nice wooden or plastic box on the back
- Some sort of interface to hook it up to my server

Now I was thinking about RS232/COM since I have it sitting there doing nothing. I actually have one external and one internal header. So that's what I would intend to use.

Other option would be USB with a FDTI (or was it FTDI?) chip or some type of chip by Cypress Semiconductor.

Electrically, I think I'll be putting the LEDs in there as a couple of bars. Each bar can be filled from 0 to all.

Maybe a grid would be smarter, but then they might flicker if the refreshing frequency is too low, or if seen with a camera. So I don't want a grid. Might be a very stupid idea to not want a grid (so convince me otherwise? )

The display will be rolling statistics as a graph (bar, or line, or filled line, I don't know yet) from right to left. (Or maybe the other way?)

Maybe I want to pipe webserver activity via a ssh tunnel to it. Or the temperature of my drives? My 8xTB disks would provide with enough data to fill a display.. Or network activity.. per port?

Anyway, as you can imagine, such a simple display, just some LEDs can be used for a LOT of things.


Now as I am quite good with a soldering iron, and have gained some linux experience over the years, I would like to bring that together to make something that I can realize this idea. (hmm, maybe I should add fading to the LEDs? So it can have contrast/brightness.. hmm)

Is there anyone reading this with some information on what the easier thing is on linux?
A USB controller? Some logic on a COM port? Both? (So many arguments and old vs new solutions on google..)

Is there a prefabricated framework or driver for matrix displays? (Not that I could find..)

Or maybe someone with a similar project?

Either interface is workable, but (in my opinion), not practical at all.

There are MANY SNMP monitoring packages out there now, like Zenoss, Nagios, Big-Brother, etc., that run a central web-page, with graphs, trending, etc. A physical monitor wouldn't be much good, unless you could SEE it, so putting it within distance of the computer that you're ON, wouldn't be as much use as the existing desktop widgets.

If you had to have a physical device, put an embedded system in it, and make it use SNMP over a network/wireless connection.

Well, the server is in a closet 4 meters away. So it might indeed not be practical to run a usb or serial cable over that distance (including hiding the cable out of sight).

I do have a couple of spare linux-embedded routers, and some of them have at least one form of external communication.

My day to day workstation is a PowerMac G5, but it's not on 24x7x365.. The linux servers are always online so it'd be nice to waste those LEDs on a project connected to that in some way. I could also make stars on my ceiling and have linux control the blinking but that's such a cliche!

However, embedded linux with usb 1.1 or a simple serial interface would be okay for what I want, right? It could even be wireless! (And run on batteries if needed). I could also add some hardware buttons to control different sources to display! Then I'd need an embedded snmp lib and maybe a daemon or cli utility to use with a shell script or program my own C app (learning phase at that..)

No that would be more practical, right? I do have a full x86 machine and a "17 TFT panel, but that's just a waste on a simple resource monitor..