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Do you want everything handed to you on a silver platter? You never even said what the specs are for the LEDs you want to use. Whats their forward voltage? How many are you going to use? How many volts is your motorcycle?
Russlk, the first reply you got, explained how to size the resistor for your LED/s. PWM was suggested by cadstar and myself. This would allow for a running light and a brighter brakelight.
and like I said, use the search button! Look up PWM if you don't know what it means. Look up ohms law. Look up sizing resistors for LEDs, look up brakelights, theres alot of stuff already here if you take the time to dig.
I guess its just what Im used to.
on our other forums, many others.
when someone, say, needs to know the resistance for the stator on a 2004 Gold Wing, someone generally points them in the general direction of where a post was made if any.
I am just used to a different crowd I guess.
I searched LED brake light as you said, and found nothing of intrest to me at all.
as far as how many LEDs I plan to use, 80 red and 4 white, all super flux.
the bike is 12V and can produce as much as 13.6
I have done similar mod for my bike (Bajaj Pulsar). But I have not added pulsating function. Its just "LED light". And I have used separate LED for brake and tail lamp. So two different resistors are not required.
I have two parallel sets of LEDs connected in parallel. (making 24 LEDs in total). So for tail Lamp 8 LEDs and for brake 16 LEDs. I feel its enough for its purpose. No PWM or any hi-fi technique needed.
The LEDs i used were rated at 25-30ma with 2.5V, I took source voltage @ 12V
so R= (Vs-Vl)/I
=(12-(2.5*4))/30ma
=0.66 ohm~100ohm
Note: I think I have given enough info about your query. Now take back your words about this forum. Its really a dream land for people interested in electroncis. (any way by looking at your post i could see that you are not)
I have one prototype Tail/brakelight that I have built, I used 2 sets of resistors for the 2 functions.
What I am looking for here is a way to refine it while I am rebuilding my bike, I have about a month worth of work to do before the bike is ready for the tail light.
what I did was put the leds in groups of 4 and used 3 resistors for the tail and 1 resistor for the brake and ran seprate wires to each group.
when I was finished I ended up with 33 sets of wires coming off the board, it looks like a birds nest.
I would like to come up with a way to do away with all the wires for the next LED that I am going to start on and figure a way to make the LEDs to pulse 3 times when the brake curcuit is activated.
I dont know the formula to figure the resistors that I will need.
The spesifications are as follows:
Absolute maxium ratings.
Foreward Current, symbol (If) Rating 50 units Ma
Pulse foreward current " IFp " 100 " Ma
Power dissipation " Pd " 120 Mw
IFP conditions_ pulse width-< 10msec and duty -< 1/10
Electrical Optical Characteristic (TA=25)
Parameter Symbol Condition Min. Typ. Max Unit
Foreward voltage VF IF=20MA / 2.0 2.4 Vf
Reverse current Ir Vr=5v / / 10 Ua
Luminous Intensity Iv If=20Ma / 6000 8000 Mcd
The supply voltage will be between 12v and 13.6 volts
any help with will be appreciated
I would like to come up with a way to do away with all the wires for the next LED that I am going to start on and figure a way to make the LEDs to pulse 3 times when the brake curcuit is activated.
Anyway you can look up the data sheet for the LED you wish to use and find the voltage drop across it. Most of the low power red LED's are about 2V (I don't know what it is for the higher power ones). You then connect enough LEDs together (in series) to make a voltage drop of just under the battery voltage (I don't know much about vintage bikes but lets say it is a 6V battery you would connect 3 LED's with a 2V drop). Finding the voltage difference between the maximum system voltage (i.e. charging voltage) and the value of your LED voltage drops. You then select a resistor that limits the current to the value indicated in the data sheet.
Simply parallel enough of these together to make the tail light.
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