Daft Punk coffee table

Hi there,

Ive been roped into helping my flatmate make a Daft Punk style/replica coffee table. For those that havent heard of this before its essentially a table with a 5x5 grid of red illuminated panels underneath a glass top. Each square can be turned on or off and they dance around forming predefined patterns.

There is video of it on youtube here: Daft Punk Coffee Table - YouTube

For the construction of the table itself my flatmate is going to be following this instructables guide: http://www.instructables.com/id/How-to-build-a-Daft-Punk-Table-Replica/

However the guide makes no real mention of how the microcontroller works. My background is in computer programming and ive got some basic electronics experience so the Arduino Diecimila seems like a perfect choice to control the lights.

I was planning on mounting 8 red LEDs in each square. Each square would then be attached to a digital output on the arduino (possibly needing some transistors inbetween, can the arduino power 8 leds from one of its outputs?). However the Diecimila only has 14 digital outputs, and I need 25 (5x5 squares) for the table.

What is going to be the easiest way to do this, remembering that im not that hot with electronics. I was thinking about strobing the LEDs or some sort of binary output but then it all got a bit too much for me :-?

Cheers,
James.

For driving many leds individually you have 2 options:

  1. so called shift registers
  2. MAX7221 IC

To add enough juice, each segment needs a transistor or a chip with transistors.

If you go for the 595's and transistor chip and use single leds, best go for an open collector driver (like ULN2803). This chip will give you 8 pins and can drive 500mA per pin.

The MAX7221 chip can drive 64 leds (or segments of leds), and has a build in brightness controll (all leds at once).

If you want or need individual brightness ( or colour :slight_smile: ) control for each segment, you'll have to invest some more brains. This would basically boil down to turning each led on for a fraction of a time to give it some brightness value and then switch to the next led. If all leds are scanned very quickly it will seem like a static intensity profile. If you google for pulse width modulation (PWM), you'll find tons of info on this.

With a few 595's (and maybe some transistors) you could do this.

But as the table in the video is monochromatic and the segments are just on and off, I guess the 7221 is the easiest way.