Car LED tail lights strobe rate too slow

No need to ask - I saw myself when it was brand new :-) Yes, it has always flickered as strongly. And I also wouldn't think that caps would dry so much within 5 years (although not impossible if those bad chinese caps used in motherboards are used).

Hmm..that I didn't think. That made a sense, that higher mux freqencies would be more popular today.

That's one possible message.

Many years ago, I had a Mazda RX-7. One option offered was an illuminated logo mounted between the taillights. I had considered replacing the stock panel with a scrolling LED panel. The default display would be "RX 7" but with a selection of alternate messages I could call up as needed.

And the new BMWs, absolutely-every one of them. And a great many of the standard-format round and rectangular lamp units used on trucks and buses (but NOT all of them! It's fairly common to see buses here in Toronto with one taillamp exhibiting no visible strobing, and the other, of a different but still major brand, exhibiting extreme strobing as it scans across one's field of view.

DS

turn signals

There was never any such a mandate. Turn signal angles-of-visibility requirements have remained largely unchanged until a couple of years ago, when an option was inserted into the regulations for manufacturers to certify the front signals under regulations requiring *wider* visibility angles than the old specs.

But, it would also create new ones if the signals at/near the plane tangent to the front of the car were deleted.

them any slack. To > me

Your solution wouldn't help if they didn't use their signals...!

I keep fairly close track of the international research in the field, and I haven't seen any studies demonstrating that flicker of the type under discussion, whether perceptible or not, contributes to the safety performance of automotive lighting devices. Can you please provide some references? I ask because this sounds like one of those marketeering claims (compare "HID headlamps produce light that's closer to natural sunlight!") with no basis in even theoretical human-factors science.

I think this is a reference to peripheral vision's increased sensitivity to movement. Google found this:

I think the idea behind most of these products (flickering motorcycle headlights, etc.) is to take advantage of this effect. I'm not sure how much real science some of these manufacturers have done (selecting the correct rate and duty cycle) to justify their claims.

The PWM frequency used to dim taillights seems to be too high to be designed to take advantage of this effect. Also, a continuous flashing wouldn't seem to be as effective, as the human brain tends to suppress repetitive stimuli. The latest LED (and strobe) cop lights are going to randomized flash patterns to overcome this.

I don't agree; movement =E2=89=A0 flicker.

You're more charitable (or at least more diplomatic) than I am; I'll come right out and say it: Most of this homebrew nonsense =E2=80=94 flashing CHMSLs, blinking amber "deceleration lights", motorcycle "headlamp modulators" and the like =E2=80=94 are all marketeering with zero science behind them. Unfortunately, regulation of vehicular safety equipment in North America is often more about politics (who shouts the loudest) than about actual safety performance. So, we get public transit systems installing "deceleration lights" on their buses without a shred of evidence they help anything. We get the same motorcyclist foundations that baselessly parrot stupidities like "Loud pipes save lives!" lobbying for -- and getting -- permission to flash their headlamps with "modulators" all day and all night. We get completely unregulated aftermarketeers selling kits to make your car's CHMSL flash. All with plenty of hype and commonsensical-sounding but thoroughly unscientific babble about why each of these is the next great safety breakthrough.

DS

There are times that is desirable: some devices use the CRT blinking to transmit data like morse code to watches and teeny devices using just photo-sensors to receive the data. They don't work with most LCD monitors: too slow, or not bright enough.

Matt Helm had better decades ago; his T-bird convertible featured across-the-board taillights with a mike -- he spoke, it scrolled.

Have you've seen the system referred to in a post a while back? It's at:

Terry McGowan

I too have noticed this. More now with most of the newer cars. I have myocl onic epilepsy and I was worried the lights and epilepsy had something to do with each other. I something changes because I can't stand it. I did try n ew lens in my glasses, it helps slightly. Thanks for your post. Now I know I am not the only crazy out there. LoL

You must of miss the memo?

All new cars with LEDs are transmitting serial data using an unspecified protocol that transmits information to the car behind you, mainly the police, all gas analysis of the cabin.

Not only that, it transmits the peak speed within the last

This new technology alleviates the battles of those claiming to be innocent when pulled over and does not waste the officers time, time that can be better spent sitting at the donut shop, eating all JL's Boston Creams!

Just thought you would like to know that.

P.S. Watch out for cars that have auto head light dimming, I understand they may want to use that as a way to transmit kill codes to your vechical! :)

Jamie

Yup, they use PWM to switch between the tailight (when headlights are on) and brake lights. Saves having another set of LED lights. I am pretty sensitive to flicker, have no trouble seeing 100+ Hz flicker if I sweep my eyes. When I see some that have pronounced flicker I try to estimate the PWM frequency by the spacing of the dots. When I say "sensitive" above, it doesn't bother me in any way, but I do notice it.

Supposedly, it is fairly slow flashing, between 4 and 10 Hz, or so that is supposed to have an effect on epileptics. So, hopefully, these PWM taillights will not sent you into a seizure while driving. That would not be good at all!

Jon

I noticed this some time ago. When I sweep my eyes across the road one set of taillights suddenly become dozens of lights. I find it *very* disruptive and can see how this might cause someone to misjudge a situation creating an accident.

So far the only cars I have seen this on were Cadilacs of a certain vintage. I don't think this problem persists on the newer ones.

Actually, it is a silly way to dim the LEDs. To have two banks would not require *more* LEDs, just divide the present set into two sets. The problem is appearance. They are using the LEDs as styling elements with each bulb individually visible. Turn off half of them and suddenly the "look" changes. To make it look right would require a current adjustment in the two brightness levels rather than pulsing... or just pulse it faster at say, 1 kHz. Obviously there is some sort of cost issue.

It was recently that a GM executive said that they "never" sacrifice safety to save cost... absurd! Everything in engineering is a trade off, including safety. It is impossible to do otherwise.