Civinfo - View Single Post

blzb0b · 7th March 2007, 22:10

it shouldn't be too difficult to get auto-dim.. you just need two resistors

the two resistors should be different values to give the desired two brightnesses.

you will need to find two earthing points..

find a +ve connection and connect this to the anode of the led (I would suggest a lamp from behind the dash (I think there is one behind the cig lighter?)) .

then use two wires to connect to two earth points. the one with the higher value resistor to any earth point.

This will mean that anytime the lights are on - the leds should be on in their "dim" mode

the other wire with the lower value resistor (connected to the same cathode) should connect to the -ve side of the interior lamp (probably easier to get to the back of the door switch)

this will give the "bright" mode...

current will always follow the path of least resistance. so when the door is open - the path is thru the lower resistor.

+ve --Led -- H resistor -- earth
...............|
................-- L resistor -- earth (door switch)
(ignore the dots - they are just to space out the diagram (the forum seems to remove white space from the posts!)

I must stress I havn't tried this yet as my Type R doesn't arrive till the 25th... but in theory it should work...

whilst assembling - you could use a pot to determine the correct values for the brightness you want - then replace this with a fixed resistor prior to final fitting.

7th March 2007, 22:10	#12 (permalink)
blzb0b Wheelnut Join Date: 17th December 2006 Posts: 99 Thanks: 0 Thanked 0 Times in 0 Posts iTrader: (0)	it shouldn't be too difficult to get auto-dim.. you just need two resistors the two resistors should be different values to give the desired two brightnesses. you will need to find two earthing points.. find a +ve connection and connect this to the anode of the led (I would suggest a lamp from behind the dash (I think there is one behind the cig lighter?)) . then use two wires to connect to two earth points. the one with the higher value resistor to any earth point. This will mean that anytime the lights are on - the leds should be on in their "dim" mode the other wire with the lower value resistor (connected to the same cathode) should connect to the -ve side of the interior lamp (probably easier to get to the back of the door switch) this will give the "bright" mode... current will always follow the path of least resistance. so when the door is open - the path is thru the lower resistor. +ve --Led -- H resistor -- earth ...............\| ................-- L resistor -- earth (door switch) (ignore the dots - they are just to space out the diagram (the forum seems to remove white space from the posts!) I must stress I havn't tried this yet as my Type R doesn't arrive till the 25th... but in theory it should work... whilst assembling - you could use a pot to determine the correct values for the brightness you want - then replace this with a fixed resistor prior to final fitting.