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DIY light kit ?
#1

hi guys 

in the past i have wired LEDs into my cars for head/tail lights with great success
but i like the idea that the lights could remain illuminated temporarily after a deslot 
is it just a case of introducing a capacitor into the circuit ?


has anyone any experience or tips regarding this 

i know there are light kits available on the market , but trying the DIY route is part of the hobby imo

Kev
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#2

Hi Kev,

About 15 years ago, I wired LEDs into some of my cars following instructions found on www.carrera4fun.de
Here is the URL of the page : http://carrera4fun.de/3_elektronik/dauerlicht.htm
The GoldCap will do the job
[+] 1 member Likes Fred's post
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#3

Hello Kev,
With the emergence of Arduino based systems,  3.3 volts became a thing and so it is possible to buy 3.3volt regulators that are very small.  The lower voltage means that physically smaller capacitors can be used (say 5V types) such that the LEDs will remain lit for longer for the same physical space in the car.
I hate to be like some tech posters who do the development "live" on the forum but, I do have some 3.3v regulators somewhere with the intention of trying such an arrangement but have not done it yet.
Ultra bright white LEDs should be OK at 3.3volts so no need for dropper resistors but tail lights will need some so as to make them realistically bright.

Umm,  I'll have a go in the next few days.

Leo
PS - LOL, I guess this is an opportunity for me to progress with my F1 Safety Car (Red) project.

Forum Precepts:  Don't hijack or divert topics - create a new one.   Don't feed the Troll.    http://www.scuderiaturini.com
[+] 3 members Like Scuderia_Turini's post
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#4

ok 
all parts ordered as per Fred's post 
looking forward to attempting 
keenly waiting for Leo's results also  Thumbup

Kev
[+] 1 member Likes OXO cube's post
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#5

Hello Kev,
Well the 3.3volt regulator idea is basically not on.
The advantage that white LEDs operate at 3volts is actually the downfall.
The operating voltage is too close to the stored voltage of the super-capacitor, so pretty soon the white LEDs go out, although the red ones stay lit for about 2.5 minutes.

The video shows a 5volt source feeding the 3.3v regulator (in the clothes-peg) a diode then feeds the 3.3v to the super-capacitor and LEDs.  
The white LEDs are driven directly and the red LEDs have 1.5K ohm resistors in series (to dim them to a realistic level).
The diode is necessary so that the super-cap is not feeding back to the power source when the power is cut.  The diode drops 0.6v so the capacitor gets just under 2.7v and that is marginal for keeping the white LEDs lit so once the capacitor has discharged a bit the white LEDs go out.
 
For the video I wired in a green LED with the white ones and you can see that it stays lit for a bit longer. So if green headlights are your thing...

A 5volt regulator would work better but those tend to be much larger.

After I mentioned my F1 Medical Car, I remembered that for those I install a 12volt battery to power the lights. An N size battery will fit in most saloon type cars and operate for quite a long time. Of course that carries a weight penalty. An N size battery is same diameter as an AAA and 2/3rds it length.

Leo


Forum Precepts:  Don't hijack or divert topics - create a new one.   Don't feed the Troll.    http://www.scuderiaturini.com
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#6

hmmm 
thanks Leo .. but id like the front and rear lights to stay on same  Time
i got the last delivery of everything needed  for Fred's post this morning 
i got enough for 10x sets , so i got lots for mistakes  Tease
watch this space  Bigsmile
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