Custom Headlights……

[ph2t]

This is a light mod I’ve worked on as a side project from others. In building my knightrider lights and custom h-bridge and other goodies I’ve come to realise the power and potential of these DCDC converters.

The DCDC Converter

A DC-DC converter allows me to take a low voltage, say like 1.2V (our car’s battery for example) and convert it to a higher voltage like 3,4 or even 5V. Why do this? Well let me tell you that there’s not much stuff out there that runs on 1.2V that’s for sure. You might argue that the car runs on 1.2V and it does BUT the receiver circuit in the cars uses a dcdc converter as well to provide the RX2/6 chip with 3V! So there you go!

LEDs, the good, the bad, and the just plain crap

There’s many different LED’s out there. Most of you have even probably used some before in making headlights, underbody lights and so on. LED’s come in all shape and sizes, mostly 5mm and 3mm. The perfection light kit for example uses 3mm LED’s. Then there is surface mount LED’s, these buggers are really small and are fairly bright when comparing them to their larger cousins.

The problem with LED’s is one of voltage. To use some kickarse blue or white leds requires a fair bit of voltage, usually from a minimum of 2.6V to at times over 4V! This is why you need to use an external power source like (in most cases) a 3V lithium battery. The car battery is only 1.2V and prolly won’t power any led natively (even RED led’s need like 1.6V min to operate).

Another issue is not technical but one of looks. To drill two huge holes to fit 3mm leds can detract from the overall look to the car, using surface mount leds enables you to glue them on the inside of the shell and let them shine through. Obviously you need your headlights to be clear to start with for this to work. This is
just a personal preference thing with me.

So here we go

Here’s all the parts for the circuit including a custom pcb I made for the job. Using my good old “Steering Knuckle Size Comparison Test(tm)” you can get an idea as to it’s size.

As some of you have probably done from the mosfet mod, I like to glue the parts onto the pcb first before soldering them. This helps to keep them still as I solder the terminals.

All done and put together.

Here are the LED’s I’m using. They are beasts! Ultra bright white leds rated at approx 300mcd for 30mA and they need 3.9V to operate! Dang!! So small compared to the 3mm yellow led next to them.

Here’s the final setup with led’s soldered in place and a 1.5V watch battery used as the power source.

And when I close the contacts……

I’ve choosen my Skyline 2000 pullback shell ’cause it’s a nasty piece of work that needs some headlights. As you can see in the picture I have scraped away the silver coat on the inside of the shell that was obscuring the light holes. This is on the right hand side of the picture, left hasn’t been done yet.

As you can see here, I’ve used some bluetak to quickly rig up the lights. On a presentation version I superglue them in place and then paint the area with a thick black gloss to ensure the lights only shine out through the front.

This is the end product:

Not too shabby…:smiley16:

ph2t.

[barto_85]

looks awesome ph2t, keep it up.

[dgs73]

really nice… especially impressed that you bother to paint the inside of the shell; lights look great, but it does’nt look so good if the whole bonnet is partially lit…

[ph2t]

That’s true. As I stated in the thread, the photos above are of the mock-up version. When I paint the insides, you don’t see the bonnet lit up at all. I’ll get a photo of my knight rider car tonight and I’ll show you. Also look at the video posted in “lazy afternoon and a 3.8” you can see that the lights light up the area in front of the car only, no where else. Very nice…..

ph2t.

[barto_85]

yeah, your knight rider car is great, the lights work really well on that.

[ph2t]

The “lazy arvo” video is now my screensaver at work, lol!

[ph2t]

I found a photo, here you can see the lights only coming out the front.

ph2t.

[KingRX7]

does that guitar string antenna work well?

[barto_85]

I think it gives it a bit of extra range right ph2t or micro_amps?

[ph2t]

Quote:

does that guitar string antenna work well?

Yes, very well. For more info see my “guitar string antenna” thread in the technical section.

ph2t.

[barto_85]

one more post from 500 ph2t!!! dont let it be a technical one, 3 stars too! Oh yeah, word on the street is that you got a new pm.

[z-beam]

thats one of the nicest bits iv’e ever seen!
damned beautiful i must say…..

[ph2t]

Yo Z! Wassup homie? Where the fruitloops have you been lately?

[jamiekulhanek]

Dude thats awesome, that pcb is teeny.

From what i can see the PCB just has a pair of SMD caps and the voltage inverter.

What is the code on the DC-DC inverter, i have about 3 PCB’s lying around that i might get stuck into 🙂

[ph2t]

The circuit is pretty much this:

There’s also a 330Ohm resistor in series with the LED’s. The LED’s are wired in parallel.

The dcdc convertor is from http://www.onsemi.com . It’s the NCP1402 model, 5V version. I got the pcb design in CircuitMaker 2000 format. I’ll post it tonight.

Parts List:

Cin=10uF
Cout=47uF
Diode=schottky type (Low Vf)
L1=47uH
U1=NCP1402 (5V)

ph2t.

Edited by – ph2t on 19 August 2003 12:49:21

[DaveF]

Yet again, great work man! I always wonderred about painting the sides of the LED with reflective mirror or silver paint, to try and concentrate the light out the front of the LED, not up through the bonnet, but you’ve found another good solution. I also dislike the light fromthe headlights appearing under the car, but you seem to have gotten rid of that too… might be the LEDs you use. Cool.

[ph2t]

Most of it is to do with the paint I use, a thick black gloss paint applied liberaly….

ph2t.

[DaveF]

Yeah. Acts as a blocker. Even thick dull paint would do – absorbs the light.

[ph2t]

One thing I found was that when I dremeled down the front wheel wells to add space for my full size wheels the light started coming out of the plastic there. I recoated the edge of the wheel wells and all is fine now.

[jamiekulhanek]

Quote:

The circuit is pretty much this:

There’s also a 330Ohm resistor in series with the LED’s. The LED’s are wired in parallel.

The dcdc convertor is from http://www.onsemi.com . It’s the NCP1402 model, 5V version. I got the pcb design in CircuitMaker 2000 format. I’ll post it tonight.

Parts List:

Cin=10uF
Cout=47uF
Diode=schottky type (Low Vf)
L1=47uH
U1=NCP1402 (5V)

ph2t.

Edited by – ph2t on 19 August 2003 12:49:21

Ah okidoki, might get a few of those lil buggers, how much are they?

From looking at the specs, it handles a fair bit of dough, 200mah, more than enough to power a bcg motor.

[merc-blue]

hey ph2t is it likely that u could sell a couple of the light mods?

[ph2t]

See the thread in the “for sale” section.:)

[trash]

hahah, a tiny switchmode converter. I must be behind the times. I have some nice tiny little
flouro screens, the same type of thing that provides the light in LCD screens.
I could probably do some fancy stuff with them
but they are bit power hungry. Got any ideas ?

[ph2t]

trash, what do they need to run? V? I? What’s their impedance? Do you have any datasheets?

ph2t.

[jamiekulhanek]

I am quite surprised that these tiny chips can supply .2A, thats quite a bit for an SMD chip.

I am a bit worried about using those tiny watch batteries with them though, they struggle to supply the current, and an inverter would of course draw a fair bit to get the 5v or so.
i.e to get 200mah @ 5V out put probably requires around 600mah input.

[Author]

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