Strobelight Effect in Headlamps: How!

Saab Ed · 11-03-2012 4:24pm #1

A mate of mine has just asked me where can you get those strobe light effect headlamps, you know the kind that always seem to be flashing when cars are being tested around tracks on TV shows. I'm presuming its some sort of kit with bulbs but I hadn't got a clue what the answer was and to tell you the truth I'd love to know myself now. Can anybody tell me how and where these can be got.

Thanks in advance.

pa990 · 11-03-2012 4:30pm

Its a trick of the camera
A bit like trying to record an old tv screen and rolling lines would appear.

i'm sure someone with photographic expertise will be able to give a better answer

OldmanMondeo · 11-03-2012 4:39pm

These are the same as the Gardai and recovery trucks use. You should be able to get them in most proper truck places.

pa990 · 11-03-2012 5:07pm

OldmanMondeo wrote: »

These are the same as the Gardai and recovery trucks use. You should be able to get them in most proper truck places.

i think the op is talking about the drl's and rear reds appearing to strobe, Just watch Top gear to see what i mean.

This strobing is a trick of the light/camera

Chriscl1 · 11-03-2012 5:08pm

http://www.ebay.co.uk/itm/4led-Decorative-Flash-Strobe-Light-Bulbs-Car-Headlights-/260755639637

tossy · 11-03-2012 5:15pm

The flashing lights you are talking about only appear to be flashing as the refresh rate of the LEDs clashes with the frame rate of the camera - at least that's my lay man understanding of it - in other words the are not really flashing.

fullstop · 11-03-2012 5:22pm

tossy wrote: »

The flashing lights you are talking about only appear to be flashing as the refresh rate of the LEDs clashes with the frame rate of the camera - at least that's my lay man understanding of it - in other words the are not really flashing.

Same pohenomenon as a super slow-mo with a screen in the background (eg at a football match), the screen always looks to be flashing in the slow-mo shot.

Saab Ed · 11-03-2012 5:28pm

Chriscl1 wrote: »

http://www.ebay.co.uk/itm/4led-Decorative-Flash-Strobe-Light-Bulbs-Car-Headlights-/260755639637

Now this suggests a different answer to everyone else. Do you actualy cut holes in the back of your headlamps to fit these.

You're never finished learning though. I never knew that was a trick of the camera

Chriscl1 · 11-03-2012 6:30pm

I think they just fit in place if the regular bulbs. I've seen them lots on drift cars and safety cars too. I know what the above posters are saying about flashing lights on tv but tbh I've only noticed the rear led lights doing that flickering. These strobe ones look nothing like flickering led's on video playback.
http://www.youtube.com/watch?v=wXUPVnvIMxc&feature=youtube_gdata_player

rebel.ranter · 11-03-2012 6:50pm

There's two,things being talked about there:

- strobe bulbs like those listed in the EBay link

- LED headlights. The new craze that's moved the game on from Xenon headlights is the LED headlights. these will appear flicker when being filmed, but won't appear to flicker in reality.

Chriscl1 · 11-03-2012 7:05pm

I've seen led drl's but not led headlights. Do they use a projector? I thought leds make a bright light but the light doesn't travel very far so wouldn't be good for say dipped beam etc???

11-03-2012 7:27pm

rebel.ranter wrote: »

- LED headlights. The new craze that's moved the game on from Xenon headlights is the LED headlights. these will appear flicker when being filmed, but won't appear to flicker in reality.

Im pretty sure LED's aren't being used for headlights in production yet. There are issues with heat output that prevent this at the moment.

Tropheus · 11-03-2012 10:04pm

Deleted User wrote: »

Im pretty sure LED's aren't being used for headlights in production yet. There are issues with heat output that prevent this at the moment.

They are. The R8 V10 has them as standard and they are optional on the new A8 and A6. Also optional on the new CLS.

They don't use projectors from what I've seen. I wonder will we see LED headlight aftermarket kits anytime soon.

Anan1 · 11-03-2012 10:06pm

AFAIK the Nissan Leaf has them as standard.

bladebrew · 11-03-2012 10:11pm

were these on top gear last week?
i seem to remember a car with headlights flashing like this, it was in slow motion though, maybe that was the camera?
cant fecking remember which car it was though:mad:

dr.fuzzenstein · 11-03-2012 10:21pm

Deleted User wrote: »

Im pretty sure LED's aren't being used for headlights in production yet. There are issues with heat output that prevent this at the moment.

I thought LED's would have the least heat output compared to standard halogen or xenon bulbs?

Stealthirl · 12-03-2012 12:14am

ksimpson wrote: »

They are. The R8 V10 has them as standard and they are optional on the new A8 and A6. Also optional on the new CLS.

They don't use projectors from what I've seen. I wonder will we see LED headlight aftermarket kits anytime soon.

here they are

https://www.youtube.com/watch?v=8B9_ZJGHKHk

would love to see what there like from behind the wheel myself

Tropheus · 12-03-2012 12:54am

Stealthirl wrote: »

would love to see what there like from behind the wheel myself

Judging by all the bulbs involved, I'd doubt we'll be seeing aftermarket kits.

BTW, these are a €3k option on the A6. Madness.

Bruthal · 12-03-2012 1:44am

rebel.ranter wrote: »

There's two,things being talked about there:

- strobe bulbs like those listed in the EBay link

- LED headlights. The new craze that's moved the game on from Xenon headlights is the LED headlights. these will appear flicker when being filmed, but won't appear to flicker in reality.

Yes it seems to be two different things being posted about alright.

In the case of LEDs appearing to flicker, if the LEDs use pwm (pulse width modulation) as a method to control the LED brightness, or to regulate them from slightly varying voltage, then they will appear to flicker in video recordings. PWM is the rapid switching on and off of the LEDs, the ratio of on to off time being increased to increase brightness, or to stay at the same brightness for a lower voltage, and vice versa.

If they are 100% on, then there will be no flickering. If pwm is used, it can show up in video recordings, but the frequency would be too high to see seen by eye.

Bruthal · 12-03-2012 2:11am

dr.fuzzenstein wrote: »

I thought LED's would have the least heat output compared to standard halogen or xenon bulbs?

The high intensity LEDs typically have a lot lower wattage for the same light output as incandescent bulbs, and so produce a lot less heat. But the LED lamps need to have proper heat sinking for the heat that is produced.

Incandescent bulbs dont realy need heatsinking, as the light itself is produced purely by heat, and not that much of this heat is conducted to the bulb socket but is mostly radiated into the surrounding air, where as heat would ruin a high intensity LED junction, which would be trapped in the LED without heat sinking.

langdang · 12-03-2012 8:47am

robbie7730 wrote: »

If they are 100% on, then there will be no flickering. If pwm is used, it can show up in video recordings, but the frequency would be too high to see seen by eye.

Just out of interest, and at the risk of a tangent, LED traffic lights - do they flicker on purpose to attract attention, or is a side effect of an odd PWM choice, or is it some crappy 50Hz coming through?

Bruthal · 12-03-2012 3:53pm

langdang wrote: »

Just out of interest, and at the risk of a tangent, LED traffic lights - do they flicker on purpose to attract attention, or is a side effect of an odd PWM choice, or is it some crappy 50Hz coming through?

I never actually noticed that myself. Flickering to the naked eye?

langdang · 12-03-2012 4:00pm

robbie7730 wrote: »

Flickering to the naked eye?

Maybe not for normal people.... I can see it tho.

Bruthal · 13-03-2012 4:54pm

langdang wrote: »

Just out of interest, and at the risk of a tangent, LED traffic lights - do they flicker on purpose to attract attention, or is a side effect of an odd PWM choice, or is it some crappy 50Hz coming through?

langdang wrote: »

Maybe not for normal people.... I can see it tho.

I wouldnt say they are intended to be visibly flickering anyway. If they are supplied from a rectified and reduced 230v AC, but not smoothed by DC capacitors, they would go off 100 times a second per cycle, which shouldnt be noticable.
Discharge lighting such as used in street lighting, and flourescent lighting, all do that. Incansescent lights dont because they dont get a chance to cool to go off between half cycles, but they do slightly pulse on the AC supply, which can be seen in slow motion video.

If they are LED, and were PWM`d for some reason, (dimmed operation at night perhaps?), and at too low a rate, they could appear to visibly flicker. But its easy to dim LED`s right down to nothing, without ever seeing them flicker, using a few hundred micro seconds as the PWM pulse time widths.

The same setup can be used for controlling car fan speeds, something i will do on my own one if i ever get around to it, as the resistor pack has gone, so its full fan speed, or off at the moment.

positron · 13-03-2012 5:01pm

bladebrew wrote: »

were these on top gear last week?
i seem to remember a car with headlights flashing like this, it was in slow motion though, maybe that was the camera?
cant fecking remember which car it was though:mad:

I noticed it too - I think it was the new BMW M5, and it was the angel / hallow eyes part of the headlight that was flickering.

http://www.youtube.com/watch?v=64Q3PLAmHwY

Look at 3:36, 4:02, 4:13 etc

muckwarrior · 13-03-2012 5:17pm

They only flicker on camera. I use my phone as a dash cam and a couple of times I've noticed the tail lights of cars flickering/flashing on the screen but not to the naked eye.

Btw, why the hell would anyone actually want their lights to do this?

MarkR · 13-03-2012 5:22pm

http://www.ebay.ie/itm/PACE-CAR-Strobe-Lights-Pair-speed-control-NEW-/250827925055?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3a6682663f#ht_850wt_1141

Bruthal · 13-03-2012 5:24pm

muckwarrior wrote: »

They only flicker on camera. I use my phone as a dash cam and a couple of times I've noticed the tail lights of cars flickering/flashing on the screen but not to the naked eye.

Btw, why the hell would anyone actually want their lights to do this?

To do which though, visibly strobe, or flicker but only visibly on a camera/video?

positron · 13-03-2012 5:28pm

muckwarrior wrote: »

Btw, why the hell would anyone actually want their lights to do this?

Strobe effect makes the lights more noticeable - hence safer. I half thinking of doing that on my motorbike. I have seen a good people have strobe effect setup for their motorcycle's brake light, which really makes it stand out, which is a good thing.

muckwarrior · 13-03-2012 5:32pm

robbie7730 wrote: »

To do which though, visibly strobe, or flicker but only visibly on a camera/video?

To visibly strobe. It's bad enough having to deal with muppets using their foglights 24/7 or 10000000000k xenon bulbs in reflector headlamps without adding strobe lights!

Chippy01 · 13-03-2012 7:20pm

positron wrote: »

Strobe effect makes the lights more noticeable - hence safer. I half thinking of doing that on my motorbike. I have seen a good people have strobe effect setup for their motorcycle's brake light, which really makes it stand out, which is a good thing.

If you want to go that way for a bike, search for 'headlamp modulators'. They are popular in the U.S., but not all states endorse them.
Stoplamp modulators are another thing altogether, and are (imo) a good option to fit.

Strobelight Effect in Headlamps: How!

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