Rack KITT

Revision as of 01:13, 8 February 2011

A rack mounted LED array of wikipedia:blinkenlights, 1RU, which emulates wikipedia:KITTs scanner by visual, but is similar to the wikipedia:BeBox's blinkenlights for function.

What can it display?

• Status monitors
  • KITT Scanner for system load indicator
  • Fill bars for memory/cpu/disk/whatever
• Error displays
  • Guru Meditation error
  • BSOD
  • Full bright
  • red X
  • scrolling words
• Screensavers (may require multiple in sync)
  • Conways game of life
  • Matrix
  • PONG
  • Tetris
  • Flames
  • ripples
• other visuals
  • snow crash randomness (error?)
  • heartbeat (status)

A rack unit is 1.75inch high, or 44.45mm, and a 19" rack is 482.6mm wide. If we use 3mm LEDs. then we can get 9 high (means we can have a border and a 3x5 font inside), or 8 high (easier to calculate the electronics?!) and still leave room for potential airflow. (5mm LEDs could fit 8 high, but no airflow)

So at a density of 5.4575mm per LED:

• x8 high = 43.66mm - which is the recommended 0.79mm short of a RU to ensure devices can stack comfortably), then 80
• x80 width = 436.6mm = 46mm to the sides for controls/UI

Alternatively, a 16x2 LCD to display extra status/etc, would require perhaps 80mm width, so dropping the possible width of the LEDs down to around 70. (70x8 LEDs is 560 still!)

Extending the basic idea

The basic display should be standalone, but racks tend to be in servers, stacked... so there should be a way to synchronise multiple rKITTs for easier overall displays. For eg:

• KITT scanner is at the left at the start of every minute, so ALL displays sync up, and it's easier to see which is fastest...
  • say: scanner scans (a full left-right-left cycle) at X scans per 10 seconds, and only updates the speed every 10th second. That way every 10 seconds it is back to the left. 5 scans/10seconds = default. Integer scan count/10 seconds.
• most screensavers (esp Matrix) will improve across multiple lines, so a basic protocol to transmit data "down" and "up" (left/right too? probably not for this iteration)

limitations

• how many LEDs can be lit at once as powered by USB?
  • http://forums.bit-tech.net/showthread.php?p=327983 - so, maybe 20? :/ Also, ensure USB driver is correct!
  • Discussions with Brett at LCA2011 suggested closer to 80 or 100.
• how many LEDs can be controlled at what speed by PIC controllers? (PIC bandwidth?)
• how much space (depth) to build this. The idea is it can sit in FRONT of a machine in a rack cabinet
  • remember to consider rKITT heatsink issues, and server case airflow issues!

further reading

• http://www.thinkgeek.com/clearance/c58c/ - a thinkgeek product with 18 LEDs
• Have seen 36white LEDs reading lamp on ebay. USB powered.

note that Arduino will make all of this much simpler, it just wasn't around when I first came up with the idea. This page is yet to be refactored with Arduinoness :)