DIY LED Tails

[EdChen]

I noticed on my '01 GS that one of the rear tail light bulbs were out. I took the cover off and decided, instead of just getting new incandescent bulbs, or off the shelf LED bulbs, I'd make my own.

I broke open the dead bulb to use as a wire connector, then took some measurements of the lens housing and screw hole position. I drew it out onto a piece of fiberglass perf board and cut it out on the band saw. The two holes were drilled out and I went to work laying out the LEDs.

I did some quick tests and aimed for about 20mA per LED string when the brakes were on, and about 4-5mA otherwise. This seemed to make for a bright enough running light, and big enough difference between braking and non-braking. I just did a quick and dirty resistor based circuit. I had the perf board and LEDs already, so this entire thing was free except for my time.   I also noticed the clear bottom part of the lens, which I assume is to light the license plate. I threw in 4 white LEDs pointing down for that.

The fiberglass board is sandwiched between the plastic lens and the bulb housing. When I first screwed it in, there was a gap between the lens and the rubbery gasket (from the thickness of the board). I used a big drill bit and drilled a couple millimeters of the plastic screw shoulder and that allowed the lens to squish the board and mate with the gasket.

Sorry about the poor pictures, I can try take more if desired!





Let me know if those pictures don't work!

Ed

[bombsquad83]

Cool.  Nice work. 

I noticed the Illini license plate cover.  I graduated from U of I as well.  Are you still in the Central IL area?

[EdChen]

I'm up in Chicago now. Had my bike down at U of I for my last couple years there though! Where are you at?

[bombsquad83]

I'm in Bloomington/Normal.  Grew up in Mahomet and went to U of I for General Engineering.

[BockinBboy]

I noticed the plate immediately lol...  I knew we had an Illinois crowd, but didn't realize we had U of I Alums here!

I'm class of 2011, but I didn't get my bike 'til this last spring.

- Bboy

Edit: Bet I could guess your majors just by the type of work you've done to your bikes! lol

[ThatOtherGuy]

Got any pics of it illuminated, normal and brakes on?

Now what would be funky is to spell out STOP in LEDs on the board.

[EdChen]

I noticed the plate immediately lol...  I knew we had an Illinois crowd, but didn't realize we had U of I Alums here!

I'm class of 2011, but I didn't get my bike 'til this last spring.

- Bboy

Edit: Bet I could guess your majors just by the type of work you've done to your bikes! lol

I'm sure this thread is a dead give away to my major! I'm a class of 2007!

Got any pics of it illuminated, normal and brakes on?

Now what would be funky is to spell out STOP in LEDs on the board.

I actually thought about something like that! I should easily be able to put in a microcontroller to do the brake light flashing and all sorts of other animations. Maybe a proximity sensor to trigger the brake lights for tailgaters!

Oh, and I'll take some pics of the tails on and off tonight.

[bombsquad83]

Must be ECE.  I definitely enjoy fiddling with electronics too.  Class of '06 here.

[EdChen]

Must be ECE.  I definitely enjoy fiddling with electronics too.  Class of '06 here.

Nailed it!

[EdChen]

And the pictures!

First two pictures are with the brakes off:


Brakes on:


All were done without the engine running, so it should be a bit brighter.

[BockinBboy]

... Probably cant guess mine through any of my posts here like that lol... ANSC(Animal Sciences)/CHEM majors

Now don't forget the pic of yourself when you tried to get the head-on pic of the leds while still holding the brake and camera simultaneously 

- Bboy

[mustangGT90210]

That's an awesome idea! By quick and dirty resistor based circuit... I'm guessing that you added a resistor in the running light wire so it comes on very dim and then a bigger/smaller one for the brake light wire?

I've never tried anything with a resistor but I have a soft spot for anything involving lights on my vehicles

[EdChen]

I don't remember the values exactly, but I think the running light is a 910 ohm resistor, then when the brakes are hit, it essentially adds a 370 ohm resistor in parallel to the 910, almost tripling the current running through the LEDs. I can sketch out the circuit if you're interested. Its very easy to make I'd you wanted to give it a shot.

[mustangGT90210]

I'm extremely interested in trying it out, but I'm not going to ask you to draw up anything until I have the time and funds to start the project!

[Huff1371]

Nice work. Through up some schematics with values and dimensions if you can.

[EdChen]

Below is the template I used to trace out the PCB, and a rough schematic of the circuit. I arranged it so that it roughly resembles the actual physical layout.

I *think* those were the actual resistor values I used. It wasn't optimal, but it was what I had laying around. With those values:

12V:
Running Lights: (12-(5*2.0))/910 = 2.2mA
Braking: (12-(5*2.0))/136 = 14.7mA

14.4V:
Running Lights: (14.4-(5*2.0))/910 = 4.8mA
Braking: (14.4-(5*2.0))/136 = 32.3mA

I probably should have went with a slightly higher resistance than the 160 Ohm since the LEDs are rated to 20mA, but I'm not really braking for a long period of time, so it should be ok.

[xunedeinx]

Looks familiar. I did this the easy way almost 2 years ago. There's a post floating round here somewhere!