LED displays with Linux? 21
Timothy asks:
"It seems that everywhere I look I see articles about Linux/chickenwire
based MP3 players for cars that utilize a LED display instead
of an actual computer screen for outputting track information and such.
My question for you is simple: where can I find information on buying/using
a LED display in Linux. Where can you buy them, what's an
average cost for one (so I could gauge what's listed)? Would it hook up to
a serial/com device? Do you need a special card to
interface it into a computer system? How would you go about writing
information to the LED and such?"
led display (Score:1)
If all you want is to control 8 LEDs then
it takes about 10 minutes using hte parallel
port. If you want more then its still pretty
easy w/ a microcontroller.
Check out
http://www.hut.fi/Misc/Electronics/index.html
on that site are a couple PC circuits that use leds that are very easy!
Re:On a related topic, what about LED signs? (Score:2)
Google, my friend (Score:1)
It's alive! (Score:1)
On a related topic, what about LED signs? (Score:1)
Has anyone spent time using these? Where could I get a few cheap ones?
Re:LED or LCD? (Score:1)
Re:led's built into everex computers (Score:1)
Re:LED or LCD? (Score:1)
It should be a fairly easy modification to the ledstat program, though.
LED or LCD? (Score:3)
LCD is 'Liquid Crystal Display' which has this liquid crystal that's polarized and changes polarization when some electricity is run through it. This is what's used on digital watches, calculators, laptop displays and the little linux based MP3 player thingy that I've seen before.
If you're interested in the former, look on metalab (ex-sunsite) under Linux/system/status [unc.edu] you'll find that there is a led-stat.txt describing a short program and cable with LEDs, etc. (there's also a ledstatus tarball and lsm) You can modify this LED status program in a number of ways, at one place I worked we had it set up with a colored "load meter" (gets higher when more load) combined with a heartbeat (goes back and forth to give you a 'feel' of how much CPU is available) and with two of the parallel port pins hooked up to a relay hooked up to the reset switch of the NT machine next to it, so we could send a specific signal to lcdmeter and reboot the NT machine when it froze.
If you're interested in an LCD display panel, as I suspect you really are, Matrix Orbital Corporation [matrix-orbital.com] makes a series of LCD display panels (also VFD (Vacuum Fluorescent Display) modules that appear to be completely compatible and brighter than the LCD panels) that are sold through a few different channels, including Linux Central [linuxcentral.com]. These appear to use RS-232, (or I2C, whatever that is) so you'll need a spare serial port.
The software to drive these is LCDproc [omnipotent.net] which works on a fairly configurable client/server interface, so it should be possible to display anything you want with LCDproc as long as you can write a client that can speak the protocol [omnipotent.net].
Re:led's built into everex computers (Score:1)
LED cost is prohibitive. (Score:1)
Cheap LCDs (Score:2)
led's built into everex computers (Score:1)
Re:It's alive! (Score:1)
Hmmm, I should get that back to working order (I guess the kernel module will need some reworking though. It was written on a 1.2 kernel I think
And I still think that >$50 for those LCD modules is a bit steep. I think I'll have a look at our local electronic store, and see if I can't find anything way cheaper...
Regs, Pierre.
You knew this was coming... (Score:1)
Monty
(I blame everything on nvidia lately)
Re:LED or LCD? (Score:1)
You can display anything you want on it just by writing to the serial port that it is plugged into. I wrote a perl script to play around with it. It has some control characters for positioning text and doing bar graphs. Pretty neat device.
LCDproc is a program that will display proc info to these panels. It is cool too, but not neccessary if you are using it for a specific application like the MP3 players.