Parallel-port blinky-LED things (Was Re: How to make people back off...)

Article: 7959 of alt.hackers
Newsgroups: alt.hackers
From: byerr@netcom.com (*greeeeaaaaaaat*)
Subject: Parallel-port blinky-LED things (Was Re: How to make people back
off...)
Message-ID: byerrD9MDKJ.5xK@netcom.com
Organization: NETCOM On-line Communication Services (408 261-4700 guest)
Date: Sat, 3 Jun 1995 23:07:31 GMT
Approved: no.
Lines: 38
Sender: byerr@netcom10.netcom.com
Status: RO

In <19950601.193623.63@sallery.demon.co.uk> gavin@sallery.demon.co.uk
(Gavin Sallery) writes:




>Making a 'speed indicator' for my Risc PC. Actually, as a measure of system
>speed, it's utterly useless, but it serves it's main purpose, which is to
>provide some sort of visual feedback which lets me know if the system's
>crashed or not, and also provides some flashing lights, for appearances'
>sake! Basically, just hooked up a row of LEDs to the parallel port (no
>buffers circuitry - that's why I have a *real* computer), and wrote
a program
>(BASIC, would you believe - I haven't downloaded PERL yet) to do a barrel
>shift on the parallel port every time it was polled by the system. So
I get a
>little 'running light' display, which gets faster the fewer tasks there are
>running on the system. And more importantly, it stops when the system stops
>polling - sometimes useful, as you might not notice a system crash for a
>while due to the fact that the mouse pointer updates on a hardware
interrupt,
>so even if your system has crashed, you may get mouse response.

I did something similar, which you may wish to try, as it looks spiffy:

ObHack:

I did much the same thing on my Linux system (using a text file called
ledcpumeter.txt and a program called meter-0.2).  I then had a
bar-graph which displayed system load.  Not too much of a hack, since
all I had to do was follow some instructions.
Then, I got a 7-segment LED display, wired it up in parallel with the
bargraph-LEDs, added a little routine (mostly a big switch statement
to turn on the right LEDs for the letters), and now I have a little
display that scrolls my system load and free ram (albeit with only one
letter at a time).  It was easy, and impresses strangers, and is
informative.
--
Ben Byer      byerr@netcom.com     I am not a bushing
GC2.1:G!d?H+s+:g-p?+!aua--w+v-C++++US++P+L++3-EN+++K---W---
M--V--poY+t+5!jRG+tv-b+++D++B---e(see a)u+(*)h!f+n----!y

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