Difference between revisions of "Traffic Light"

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(How it works)
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We are converting a regular traffic light to a linux-peace-love?? traffic light.
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We are converting a regular traffic light to a Peace-Love-Linux traffic light.
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[[File:PeaceLoveLinux.jpg|frame|PEACE - LOVE - LINUX]]
  
 
==Materials==
 
==Materials==

Revision as of 20:14, 3 December 2013

We are converting a regular traffic light to a Peace-Love-Linux traffic light.

PEACE - LOVE - LINUX

Materials

  • 3 * 3W RGB LEDs.
  • Controller => Arduino pro mini
  • Power Supply 230Vac to 5Vdc
  • Transistors =>
  • Resistors
  • How do we gonna make the images?

Maybe it would be a good thing to make a system to mount it, so it will no longer need to lay stand on the ground.

How it works

LED properties:

  • Uledr = 2.0->2.5V
  • Uledg = 3.2->3.6V
  • Uledb = 3.2->3.8V
  • I = 350mA

resistor calculation:

  • UR = VCC - UT1 - UT2 - Uled
  • URr = 5V - 0.3V - 0.3V - 2.0->2.5V = 2.4->1.9V
  • URg = 5V - 0.3V - 0.3V - 3.2->3.6V = 1.2->0.8V
  • URb = 5V - 0.3V - 0.3V - 3.2->3.8V = 1.2->0.6V


  • R = UR / I
  • Rr = 2.4V / 0.3A = 8R
  • Rg = 1.2V / 0.3A = 4R
  • Rb = 1.2V / 0.3A = 4R

note: we use the highest voltage and a slightly lower current as safety.


The power consumption of the resistors need to be calculated

  • PR = UR * I
  • PRr = 2.4V * 0.35A = 0.84W
  • PRg&b = 1.2V * 0.35A = 0.42W

Conclusion: We will need resistors which be able to consume 2W for red and 1W for green and blue. (according to the safety standard of 25% spare)

Because we use multiplexing...

  • Rr = 8R / 3 = 2R666
  • Rg = 4R / 3 = 1R333
  • Rb = 4R / 3 = 1R333
Schematic