Difference between revisions of "Traffic Light"

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(Electronics)
(Electronics)
Line 44: Line 44:
 
The power consumption of the resistors need to be calculated  
 
The power consumption of the resistors need to be calculated  
 
* PR = UR * I
 
* PR = UR * I
* PR<sub>R</sub> = 2.4V * 0.35A = 0.84W
+
* PR<sub>R</sub> = 2.4V * 0.3A = 0.72W
* PR<sub>G,B</sub> = 1.2V * 0.35A = 0.42W
+
* PR<sub>G,B</sub> = 1.2V * 0.3A = 0.36W
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)
+
Conclusion: We will need resistors which be able to consume 1W for red and 0.5W for green and blue. (make sure the resistor reaches the safety standard of 25% spare)
  
 
Because we use multiplexing...
 
Because we use multiplexing...

Revision as of 03:14, 10 January 2014

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 DC 5V 50W
  • Transistors
  • Resistors
    • 12 * 10K
    • 6 * 5R
    • 12 * 3R
  • 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.

Electronics

Schematic

LED properties:

  • UledR = 2.0->2.5V
  • UledG = 3.2->3.6V
  • UledB = 3.2->3.8V
  • I = 350mA

resistor calculation:

  • UR = VCC - UT1,2,3 - UT4 - 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 * 0.3A = 0.72W
  • PRG,B = 1.2V * 0.3A = 0.36W

Conclusion: We will need resistors which be able to consume 1W for red and 0.5W for green and blue. (make sure the resistor reaches the safety standard of 25% spare)

Because we use multiplexing...

  • RR = 8R / 3 = 2R666 (We used 2R5 implemented as 2 resistors of 5R 1W in parallel)
  • RG = 4R / 3 = 1R333 (We used 1R5 implemented as 2 resistors of 3R 1W in parallel)
  • RB = 4R / 3 = 1R333 (We used 1R5 implemented as 2 resistors of 3R 1W in parallel)


The base resistors of the transistors we took some basic 10K resistors.


The power of the power supply

LED max current 350mA => 9 LEDs is 3.15A.

P = U * I = 5V * 3.15A = 15.75W (a 25W supply should be enough)

if we calculate the power we give the leds it wil be maximum about 3.3V(average max LED forward voltage) * 350mA = 1.155W => 9 times = 10.395W without other parts of the circuit.

Lenses and Images

I was thinking of making a mold out of wood using the CNC and use resin & hardener to make the lenses