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Discussion Starter #3
Details:
The LEDs were purchased at Digikey.
part number 160-1654-ND LED 5MM 639NM ALINGAP RED CLEAR.
These were meant for traffic signals and can handle 50mA continuous at normal temps, and I am running them at 40+mA, 5 in series, with 110 ohm current limiting resistors. I have 6 strings per side, 30 each side, 60 total. They wrap completely around the entire lense area.
I used resistors at this point just to get up and running; to see how it would work out. Future plans include either a microcontroller or analog control circuit to pulse the brake lights, and also allow each side to work with the turn signals when they are activated, while the other side continues to function as a brake light.
In wiring them up, I found that the brake light wiring was only providing about 10.7 volts. This limited the current to the LEDs quite a bit, so I used the brake switch line to switch a mosfet, and ran fused power directly from the battery to the case. I can provide a schematic if anyone is interested. Mosfets make excellent switches for power, so it would be useful for a lot of different things.
Physically, I removed the lense and scribed a line with calipers on the back side of the case, just below where the top of the case ribs would be on the inside.I then drilled holes slightly smaller than the LED bodies and press fit them into the holes from the inside. I then bent and formed the leads up and around the ribs and soldered everything. I plan to fill the entire area with electronics grade RTV, but I haven't had an issue yet with them open.
The wires for each string run along the ribbed area of the case to the front, where I have a perf board with the resistors mounted (well, that's a little misleading- it's electrical taped to the front side of the case, ha ha- only temporary). I plan to mount a small plastic enclosure inside the front part of the case for the new control board.
If anyone is interested, I will provide pictures and schematics. The LEDs were $22 per hundred, resistors are cheap, mosfets are a couple bucks each.
Last night on the way home from work (around 9:00) they threw quite a bit of light. I was very happy with them.
 

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Discussion Starter #6 (Edited)
Circuit description:
The fast 2A fuse protects all the wiring and components (and your bike). Do not wire anything into the bike without fusing it.
R1 is the current limiting resistors. Adding up (or measuring) all the LED voltage drops, subtracting that from the battery voltage, and dividing the result by R1 will give the current in amps. 1 milliamp equals .001 amp, so .040 equals 40mA.
Here is how the switching works:
First of all, the mosfet works like this: Putting a voltage that is at least 10 volts and less than 20 volts between the gate and source pins will make the drain pin short to the source pin, just like a switch. This is an N-channel mosfet, which means that it is intended to do low-side switching. You can see the the LEDs are being switched to ground, and that their power connection is always there. When the mosfet is not turned on (no gate to source voltage) it will be like an open circuit- really high resistance.
So, when the brake switch is made and sends 10.7 volts to the brake light, we steal that signal and put it to the mosfet. Some is lost in the resistor divider formed by R3 and R4, but the ratio is so large (10,000 to 330) as to be negligible. There will be about .35 volts lost across R3, but it serves an important function discussed later. R4 guarantees that the mosfet is pulled off unless voltage is applied by the brake switch (pins left to "float" can provide unpredictable results).
So, when the brake switch is made, 10.25 volts is applied to the mosfet, and it conducts.
now we come to D1. D1 is a zener diode. A zener diode will "break down" at a specific voltage. In this case, the 1n4744 breaks down at 15 volts. Notice that the connection is reversed from a normal diode so as not to conduct. It only conducts when it breaks down. What this means is that anything over 15 volts is held in check by the zener diode. R3 limits the current available through the zener so it doesn't smoke if there is an excessively high voltage. think of it this way- if there is 30 volts coming in for some reason (fault, or noise riding on the battery voltage) the zener diode keeps that gate to source voltage at 15 volts. But, the other 15 volts has to go somewhere... so it is across r3. 15 volts divided by 330 ohms gives us 45.5mA, so that is the current through that circuit. .0455 times 15 volts equals .69 watts, and the zener is good for 1 watt. See why R3 is important?
So, why limit the gate to source voltage to 15 volts? Because mosfets will go up in smoke if you exceed 20 volts. This is true EVEN IN HANDLING THEM, so static electricity will kill them. Touch a grounded metal surface before handling them so you don't kill them with static, and don't work in an environment where static is a problem. The zener protects the mosfet, and once everything is soldered in you have nothing to worry about.
Note that the mosfet is perfectly capable of switching all the LEDs. I have all my strings of LEDs connected to the Drain of 1 mosfet. Works great!
If anyone wants to do high-side switching, I can also provide a circuit for that. It is more typical to switch the high side for power. I used low side for the sake of simplicity.
 

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Circuit description:
The fast 2A fuse protects all the wiring and components (and your bike). Do not wire anything into the bike without fusing it.
R1 is the current limiting resistors. Adding up (or measuring) all the LED voltage drops, subtracting that from the battery voltage, and dividing the result by R1 will give the current in amps. 1 milliamp equals .001 amp, so .040 equals 40mA.
Here is how the switching works:
First of all, the mosfet works like this: Putting a voltage that is at least 10 volts and less than 20 volts between the gate and source pins will make the drain pin short to the source pin, just like a switch. This is an N-channel mosfet, which means that it is intended to do low-side switching. You can see the the LEDs are being switched to ground, and that their power connection is always there. When the mosfet is not turned on (no gate to source voltage) it will be like an open circuit- really high resistance.
So, when the brake switch is made and sends 10.7 volts to the brake light, we steal that signal and put it to the mosfet. Some is lost in the resistor divider formed by R3 and R4, but the ratio is so large (10,000 to 330) as to be negligible. There will be about .35 volts lost across R3, but it serves an important function discussed later. R4 guarantees that the mosfet is pulled off unless voltage is applied by the brake switch (pins left to "float" can provide unpredictable results).
So, when the brake switch is made, 10.25 volts is applied to the mosfet, and it conducts.
now we come to D1. D1 is a zener diode. A zener diode will "break down" at a specific voltage. In this case, the 1n4744 breaks down at 15 volts. Notice that the connection is reversed from a normal diode so as not to conduct. It only conducts when it breaks down. What this means is that anything over 15 volts is held in check by the zener diode. R3 limits the current available through the zener so it doesn't smoke if there is an excessively high voltage. think of it this way- if there is 30 volts coming in for some reason (fault, or noise riding on the battery voltage) the zener diode keeps that gate to source voltage at 15 volts. But, the other 15 volts has to go somewhere... so it is across r3. 15 volts divided by 330 ohms gives us 45.5mA, so that is the current through that circuit. .0455 times 15 volts equals .69 watts, and the zener is good for 1 watt. See why R3 is important?
So, why limit the gate to source voltage to 15 volts? Because mosfets will go up in smoke if you exceed 20 volts. This is true EVEN IN HANDLING THEM, so static electricity will kill them. Touch a grounded metal surface before handling them so you don't kill them with static, and don't work in an environment where static is a problem. The zener protects the mosfet, and once everything is soldered in you have nothing to worry about.
Note that the mosfet is perfectly capable of switching all the LEDs. I have all my strings of LEDs connected to the Drain of 1 mosfet. Works great!
If anyone wants to do high-side switching, I can also provide a circuit for that. It is more typical to switch the high side for power. I used low side for the sake of simplicity.
You are clearly the master of your domain! :D
 

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I try... always learning something new. Get me in with that high voltage and 3 phase, and I'm worthless. :sad1:
HA!
The utilities call ME low voltage! LOL.
 

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Why did I somehow know I would find this on here :thumbup:

Very interesting as I have this type of case from my GS and was thinking about doing this... though I seem to be wiring inclined =|
 

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I'm looking at doing something like this to my JC Whitney.
I just installed the Admore light kit for a buddy on his Givi side cases and was wondering if anyone has seen a mini controller that will split the signal for brakes and running lights plus do blinkers like the admore.
Im looking at the LED strips like the second video, but going to run 3 bands on left and right and would like to incorporate turn signals also.
Mike
 
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