Comments on: Massive LED screen project

By: JD

JD — Thu, 02 Jul 2009 20:07:10 +0000

This is awesome. I’ve thought about building one, until I did the math of how much the LEDs would cost. RGB LEDs of significant brightness are multi-dollar items (even in bulk), which makes a small panel thousands of dollars. Unless you don’t care about brightness, then its still $1000.

By: Dale Kubin

Dale Kubin — Thu, 02 Jul 2009 08:45:30 +0000

It was a typo. 32×32 =1024. The LEDs are RGB so there is acutally 3072. We did it with BASIC to show it could be done. 115,000 ips is a complete command loop. This wouldn’t change much even if it were in C. The renesas CPU is true 32bit AVR is 8bit. The AtomPro is available for less than $50.00. It has a graphic in circuit debugger where most don’t.

There will be more. Next is a wall of 40.

By: adc

adc — Wed, 01 Jul 2009 21:22:02 +0000

@ frank

I believe those are RGB leds, no need for the *3

By: Frank Groeneveld

Frank Groeneveld — Wed, 01 Jul 2009 20:25:15 +0000

Hmm, actually, the original post says 1000 leds, I wonder if their calculator was written in BASIC too: 32*32*3 == 1000?

By: Frank Groeneveld

Frank Groeneveld — Wed, 01 Jul 2009 20:23:14 +0000

32*32*3 = 3072… Woow, that’s a lot of leds…

By: bronko

bronko — Wed, 01 Jul 2009 18:19:31 +0000

is there more information about the display ? their website doesn’t give more info away.

andres:
its exactly how rossitron mentioned, every frame is repeated several times to achieve 140Hz. but the high output framerate is only necessary when filming the display or making pictures because of the short exposure time speed of the camera.
most commercial displays have 400-800Hz and you can test them using a SLR camera and setting the exposure time to 1/800s or below.
its because the brightness of the LEDs is controlled through a PWM

By: Hacksaw

Hacksaw — Wed, 01 Jul 2009 16:12:25 +0000

I wired communications for the 2008 republican national convention.the giant screen behind the stage was an array of a commercial version of this project…all I can say is AWESOME I have been wondering if there was someone working on a DIY version this is too cool!

By: watavr

watavr — Wed, 01 Jul 2009 11:05:21 +0000

$70 ???

You can get a more powerful avr128 stamp from futurelec for $20…

http://www.futurlec.com/ET-AVR_Stamp.shtml

By: Agent420

Agent420 — Wed, 01 Jul 2009 10:37:29 +0000

… speaking of which, I note this micro module is specd at 115000 instructions/sec… That seems rather slow in today’s multi-mhz age.

And $70 seems a bit expensive for a micro module.

By: Agent420

Agent420 — Wed, 01 Jul 2009 10:21:22 +0000

@ reklipz : “… Firmware was written in BASIC …” Suspicions confirmed!

There’s nothing inherently wrong with BASIC, provided you use an effecient compiler rather than an interpreter as this product uses. The Bascom Compiler for the AVR micros is an excellent example of how well this can be done.

I find many modern implementations of Basic to be very power and easy to use, often able to code more quickly than C, but C has the definite advantage of being a standardized language with cross compatibility.

By: TheKhakinator

TheKhakinator — Wed, 01 Jul 2009 08:31:30 +0000

This ROCKS… hope they’re buying at wholesale rates.

By: Jeremy C

Jeremy C — Wed, 01 Jul 2009 04:49:54 +0000

Pretty awesome though.

By: Jeremy C

Jeremy C — Wed, 01 Jul 2009 04:49:38 +0000

Wow, that has to be really expensive… My experience with industrial Leds are one that size would be hundreds of dollars – that’s for a 1 color light. Hopefully this guy has a good hook up.

By: Mike

Mike — Wed, 01 Jul 2009 04:29:29 +0000

This reminds me of Kevtris’ “display of doom” display. He hasn’t updated the blog in a while, but his latest posts are:

http://blog.kevtris.org/?p=24
http://blog.kevtris.org/?p=23

48 x 32″ display requiring 12 power supplies and a big blower fan to keep it all cool.

From the pictures, he’s using it as a gameboy display. Awesome!

Mike

By: andrew

andrew — Wed, 01 Jul 2009 04:23:08 +0000

for me, the step from basic to c was a lot easier than i thought it would be. it also feels really good to know another language :)