Difference between revisions of "Traffic Light"
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Revision as of 12:53, 10 December 2013
We are converting a regular traffic light to a Peace-Love-Linux traffic light.
- 3 * 3W RGB LEDs.
- Controller => Arduino pro mini
- Power Supply DC 5V 50W
- 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.
- Uledr = 2.0->2.5V
- Uledg = 3.2->3.6V
- Uledb = 3.2->3.8V
- I = 350mA
- UR = VCC - UT1 - 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 * 0.35A = 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 (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