Loco lights flickering?

[AndrueC]

If you look on the video below the headlight on the blue Class 68 (pulling the aggregate hoppers) are strobing. It's not visible to the naked eye but I was wonder if this was a known issue and if there was anything I could change on my phone or perhaps the decoder to avoid it?

 

 

[WIMorrison]

LEDs flicker when 'filmed' due to the strobing effect caused by frequency of the frame rate on the camera and the frequency of the LEDs. The Mk1 human eye cannot see it because it happens too fast and our eyes have a persistence of vision that cameras do not.

 

It is extremely common, the better cameras have techniques to get around it.

[Dagworth]

I presume you have turned the brightness of the lights down in the decoder settings? This is done by switching them on and off extremely rapidly. If you put them to full brightness they will stop flickering like that but will probably be too bright. The only real solution is to change the resistor values on the light circuits.

 

Andi

[AndrueC]

2 minutes ago, Dagworth said:

I presume you have turned the brightness of the lights down in the decoder settings? This is done by switching them on and off extremely rapidly. If you put them to full brightness they will stop flickering like that but will probably be too bright. The only real solution is to change the resistor values on the light circuits.

 

Andi

I haven't adjusted them at all - didn't know I could. If that means they could be adjusted brighter by removing the strobing then that's something I'd like to investigate. I have several Class 68s and their lights all appear too dim to me.

[Dagworth]

What decoder do they have fitted?

[AndrueC]

4 minutes ago, Dagworth said:

What decoder do they have fitted?

Good question. I'll need to put them on my programming track to find out as they were all bought DCC Fitted. Guess that'll be a job for next week - I also want to get my Bubble car on the PT to investigate its outrageous top speed.

 

I wonder if I should get them onto the PT (it's in my yard) using the Hand of Dog or by moving them there by rail...?

 

😁

Edited April 20 by AndrueC

[AndrueC]

Manufacturer 154, ver 4.

 

So that's Dapol. My guess would be an Imperium Next 18. That makes sense since they make the loco but I can't see anything in the CV list that relates to light brightness unless 'dim value' is the one?

[WIMorrison]

You can try adjusting this value CV123 upwards from 32. The max is probably 254, and that will be very bright.

 

[AndrueC]

I found time to have a bit of a play around. I think setting the value up to 255 does make them brighter but it was hard to be sure since the room with the layout was in full sun. But I could see the flicker with my eyes. Whether that's just because I was looking more closely or because of the different values I put in I don't know.

 

I should have more time this week so will investigate further. I have other Class 68s on the layout so I can see if those also flicker. I can say that to my eye they don't.

[WIMorrison]

another interpretation of CV123 is that it is a Boolean value i.e. on or off. It may be that 32 switches the dimming on, and that 0 may switch the dimming off.

 

However altering the brightness will not overcome the effect of the camera frame rate. You can see a similar effect with single LED lights in many cars, or around the house. Where a matrix of LEDs is used it may be less apparent.

 

Why do LEDs flicker?

Edited April 21 by WIMorrison
added URL

[GrumpyPenguin]

22 hours ago, WIMorrison said:

LEDs flicker when 'filmed' due to the strobing effect caused by frequency of the frame rate on the camera and the frequency of the LEDs. The Mk1 human eye cannot see it because it happens too fast and our eyes have a persistence of vision that cameras do not.

 

It is extremely common, the better cameras have techniques to get around it.

Summed up perfectly - you can also get a similar effect from vehicle LED lighting on Dashcams.