traffic lights with white led lights instead of colored diy

[[email protected]]

let me start with that i know basically nothing, i thought it would be a good project for my dad and i to do. Anyway, i have been searching online forschematics for a traffic light controller. i have found plenty,But none ofthem have it with white leds( i have a full size traffic light with the colored lenses. so i only need white leds) also i have found that there are different schematics for white and colored leds. so i am looking for some help for a schematic and a parts list. if anyone can help in laymans terms that would be greatly appreciated

 

[[email protected]]

let me start with that i know basically nothing, i thought it would be a good project for my dad and i to do. Anyway, i have been searching online for schematics for a traffic light controller. i have found plenty,But none of them have it with white leds( i have a full size traffic light with the colored lenses. so i only need white leds) also i have found that there aredifferent schematics for white and colored leds. so i am looking for some help for a schematic and a parts list. if anyone can help in laymans terms that would be greatly appreciated

also i think i should be using about 5 leds per color, i hope it will be bright enough

 

[[email protected]]

They use colored LEDs for better efficiency. Why use white LEDs,

then waste the light in the filters?

i fear the colors will get lost and not be as bright

 

[[email protected]]

i fear the colors will get lost and not be as bright

Colored LEDs will be brighter for the energy used because you won't be losing
(as much) energy in the filters. The appropriate color LEDs really is the way
to go. Greens, especially, can be very efficient (bright).

 

[o pere o]

let me start with that i know basically nothing, i thought it would

be a good project for my dad and i to do. Anyway, i have been
searching online for schematics for a traffic light controller.
i have found plenty,But none of them have it with white leds( i
have a full size traffic light with the colored lenses. so i only
need white leds) also i have found that there are different schematics
for white and colored leds. so i am looking for some help for a
schematic and a parts list. if anyone can help in laymans terms that
would be greatly appreciated
I would start with any schematic you found, that is, with colored LEDS.
(I have found this: http://lumberjocks.com/souichiro/blog/21142 which
may not be the one you found, but it won't matter)

To drive white LEDs you just have to tweak the limiting resistors
(R4..R6 in the link). To be safe, begin with the biggest value in the
schematic (probably the red one) and decrease the resistance until it
looks bright enough (or the ammeter connected in series with one LED
gives the value stated in the LED's datasheet).

Pere

 

[[email protected]]

be a good project for my dad and i to do. Anyway, i have been
searching online for schematics for a traffic light controller.
i have found plenty,But none of them have it with white leds( i
have a full size traffic light with the colored lenses. so i only
need white leds) also i have found that there are different schematics
for white and colored leds. so i am looking for some help for a
schematic and a parts list. if anyone can help in laymans terms that
would be greatly appreciated

I would start with any schematic you found, that is, with colored LEDS.
(I have found this: http://lumberjocks.com/souichiro/blog/21142 which
may not be the one you found, but it won't matter)

To drive white LEDs you just have to tweak the limiting resistors
(R4..R6 in the link). To be safe, begin with the biggest value in the
schematic (probably the red one) and decrease the resistance until it
looks bright enough (or the ammeter connected in series with one LED
gives the value stated in the LED's datasheet).

You already have a shunt resistor built into the circuit. Just measure the
voltage across it and divide by its resistance to find the LED current.

 

[o pere o]

You already have a shunt resistor built into the circuit. Just measure the
voltage across it and divide by its resistance to find the LED current.

Absolutely true !

 

[ehsjr]

be a good project for my dad and i to do. Anyway, i have been
searching online for schematics for a traffic light controller.
i have found plenty,But none of them have it with white leds( i
have a full size traffic light with the colored lenses. so i only
need white leds) also i have found that there are different schematics
for white and colored leds. so i am looking for some help for a
schematic and a parts list. if anyone can help in laymans terms that
would be greatly appreciated

I would start with any schematic you found, that is, with colored LEDS.
(I have found this: http://lumberjocks.com/souichiro/blog/21142 which
may not be the one you found, but it won't matter)

Nice starting place. To the op: With the one at that url,
you could move D4 to base of T1, & D6 to base of T3 to get longer
green & red on times, and shorter yellow on time. As drawn, it
gives equal on times for all three colors.

Ed