DIY LED Array Marquee For Your PC 128
An anonymous reader writes "Ever wish you had one of those big LED displays to keep you up to date on e-mails, stock quotes, server uptimes, or weather? Here's a new video tutorial showing how to build your own computer-controlled LED array. You can code your own data feed, and just send it over a TCP socket. This looks like a fun weekend project for someone looking to get started with electronics by building something useful."
Re:Now... (Score:2, Informative)
Here you go:
http://www.thinkgeek.com/gadgets/car/afe6/ [thinkgeek.com]
I've been thinking about one of these, but am a little worried that I'll end up getting shot or something when I piss off some idiot with a gun in the glovebox.
Re:Now... (Score:5, Informative)
Yes but be ready for a ticket and a "fix it ticket" to require removal of said device. Most states make it illegal for a illuminated sign to be in view of drivers on a moving vehicle. TAXI's and delivery cars have a waiver and the signs are not in the line of sight.
It's so cute... (Score:5, Informative)
I remember when I first realized that you could double your row-column population. Then I extrapolated it to its logical conclusion... that you could connect n(n-1) leds where n is the number of control lines. I was so proud! Then in an unrelated search I learned that not only was this an established technique, but it even had a cute name: Charlieplexing.
There's a neat little story here:
http://www.maxim-ic.com/appnotes.cfm/an_pk/1880 [maxim-ic.com]
Not Slashdotted Anymore! (Score:5, Informative)
Hi all,
We had tuned the www.NerdKits.com [nerdkits.com] site to survive slashdottings with its old PHP backend, but we recently started experimenting with some Django [djangoproject.com]. Django is great as a programming framework, but I suppose we have discovered that our tuning of the server settings isn't quite up to handling a Slashdotting! We've temporarily disabled that stuff so the site is back and running. My apologies for the downtime.
- The NerdKits Team
Re:Ah, brings back memories... (Score:3, Informative)
To clarify, each display board had a number of serial-in parallel-out TTL shift registers across the top of the board. The parallel outputs went to latches (or maybe the shift registers had latched outputs?) which went to the column drivers. I think there were about 800 LEDs total on the two boards, so quite a bit larger display than this kit! The addressing technique used by the kit would be impractical for this size of display.
It would bang out the bits, latch the outputs, turn on the row driver, and start banging out the next line.
It was BRIGHT and the power supply, even though switching, was hefty. Probably drew as much as a PC power supply.
Re:Now... (Score:3, Informative)
If you do use a DC psu make sure you buy one that is explicitly designed for use with automotive power. Automotive power while "nominally" 12V has a wide voltage range depending on current conditions (whether the engine is running, if so how fast, if not the condition of the battery etc)