Difference between revisions of "Traffic Light"
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We are converting a regular traffic light to a
We are converting a regular traffic light to a --traffic light.
Revision as of 20:14, 3 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 230Vac to 5Vdc
- Transistors =>
- 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
- Uledr = 2.0->2.5V
- Uledg = 3.2->3.6V
- Uledb = 3.2->3.8V
- I = 350mA
- 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