Editing LED window display (section)

===Arduino===

For the arduino side of the code, we are using code from the QC Co-Lab's Lightwall Project.  You can find their write up of their code here:

https://www.qccolab.com/LightWall

We've modified their code pretty heavily-- they disabled the serial port in their implementation.  We also enabled the ability to write to 16 strands from one arduino at a time.  

https://github.com/rblake/BmoreNodeSign

The time values used in the code were determined by hooking up the code to an oscilliscope and measuring how fast it took to adjust the wires.  

We've set the bps to 500000 as per the forum post below:
http://arduino.cc/forum/index.php/topic,98364.0.html
For the version of the code that writes 16 strands at once, a single frame takes 6144 bits to send.  FPS is related to bit rate by

FPS * 6144 = bps

With 500000 bps, each frame will take 12.288ms to send.  Each light frame takes .82ms*num_lights to display (sherwin => 19.68ms, ours => 26.24ms).  This means each frame takes 31.968 ms to send, max, which is about 30 FPS.  

For Sherwin's display, we are going to use the same 16 strand version of the code.  It's possible we could save some time by removing 4 bits from the data stream, but the timings for the arduino are fairly tight and I'm not sure it would be able to unpack the data quickly enough.

Delays in the code have been set using an oscilliscope on an duemilanova atmega328

====TODO====

*The code we're using now disables all interrupts while it's writing to the lights because it wants to get the timing absolutely correct.  This means that it can't recieve any serial data.  We've fixed this by having the arduino write an "OK" back to the server, and make the server pause until it recieves this go-ahead.  If this creates too much slowdown though, we need to tmplement the writing of the lights as an interrupt routine, which would require a bunch of work.  Doing things the interrupt way would shave off 12.28ms from the render time.