Difference between revisions of "LED Matrix Failure"

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(Goal)
(Layout)
Line 14: Line 14:
  
 
* Left->Right Left->Right
 
* Left->Right Left->Right
 +
The Dotstar LEDs are arranged in a chained sequence. the intention was to cut the strips and align them with on the fabric in a left to right sequence similar to tradition LCD panels. this sequence is typically something like this for an 5x5 pixel example:
 +
<pre>
 +
01 02 03 04 05
 +
06 07 08 09 10
 +
11 12 13 14 15
 +
16 17 18 19 20
 +
21 22 23 24 25
 +
</pre>
 +
 +
the issue with this that to implement this with the LED strips, two wires need to connect the end of one LED strip to the beginning of the next, in the 5x5 pixel example above, the SPI clock and data need to connect from the end at 05 to the beginning of the next line at 06. this creates a wiring nightmare on the back side of the design:
 +
[[File:Backside-wiring-led.jpg|300px]]
 +
[[File:Backside-closeup-led.jpg|300px]]
 +
 
* Left->Right Right->Left
 
* Left->Right Right->Left
 
  
 
= Connections =
 
= Connections =

Revision as of 12:07, 2 September 2015

Goal

Document the failure and redesign of a LED Matrix display consisting of 30 strips of Adafruit Dotstar LEDs.
LED-matric.jpg

Components

Layout

  • Left->Right Left->Right

The Dotstar LEDs are arranged in a chained sequence. the intention was to cut the strips and align them with on the fabric in a left to right sequence similar to tradition LCD panels. this sequence is typically something like this for an 5x5 pixel example:

01 02 03 04 05
06 07 08 09 10
11 12 13 14 15
16 17 18 19 20
21 22 23 24 25

the issue with this that to implement this with the LED strips, two wires need to connect the end of one LED strip to the beginning of the next, in the 5x5 pixel example above, the SPI clock and data need to connect from the end at 05 to the beginning of the next line at 06. this creates a wiring nightmare on the back side of the design: Backside-wiring-led.jpg Backside-closeup-led.jpg

  • Left->Right Right->Left

Connections

  • power connections
  • long wires
  • broken flex pads

Signal Issues

  • long SPI signals
  • quick fix

PCB Design

  • signals
  • layout
  • features
  • eagle files
  • soldering