Can I replace globes with LEDs in stock Eurovox deck?

[holdenrules]

Hi all,

A few of the globes in my stock Eurovox deck have blown and rather than replace them with globes that will blow again (I'll be buggered if I have to pull the whole dash apart again :b: ), has anyone replaced them with LEDS?

I've noticed that the board the globes are soldered to show provision for resistors (they just have links soldered there instead, as they are 12v globes), so it looks like it can take LEDs, but just need to know which LEDs and resistors to use?

I guess they would probably have to be surface mount LEDs, (wider angle of light?) as I've tested a few different types behind the facia and they don't seem to light up as well as the globes do (light shines in all directions with globes, but LEDs seem to be in one, concertrated direction.)

Anyone have the Tricky Dicky / Jaycar part numbers that they've used? :unsure:

Thanks heaps,

 

[dephilile]

The more current that passes through the LED the brighter it will be. The values of the resistance will vary depending on the specific LED that you use although I imagine they would all run on similar figures. The following calculations are based on the specifications in the following datasheet.

http://www.farnell.com/datasheets/46315.pdf

note it’s typical forward voltage value of 4.5 volts. Go above 4.5 volts and say goodbye to LED. Yes, it does have a max voltage of 5.5 volts but it wouldn’t be a good idea to operate the LED at this voltage continuously. Scroll down to page two and you will see a forward current Vs forward voltage and relative intensity Vs forward current graph. Ok. So say you want to operate it at 100% of its brightness. Looking at the relative intensity Vs forward current graph we can see that for this to be reached 20mA of current are required. We then look at the forward current Vs forward voltage graph to see that at 20mA the voltage drop across the LED will be about 4.3 volts.

Using some sort of analysis (i think its called mesh) the sum of the voltages around the circuit need to be zero. Assuming a voltage source of 14 volts and the voltage drop across the LED to be 4.3 volts and the current about the circuit to be 20mA we can write

14 = 20mA*R + 4.3volts

this gives us a resistance of 485ohms. Round this up to 500ohms because I don’t think you can buy 485 ohm resistors.

I’d double check the voltage the lamps run on before using 14 volts as the voltage in the above calculation.

In general, LED’s require between 0.5 and 0.7 volts to turn on. They can handle large currents for short period of time (I know of some applications where to get the brightness required to transmit data over a considerable distance the engineers were pumping something like 20 or 30 amps through them for tenths of a second). Why they didn’t use infer red LED’s is beyond me. Also, Blue LED’s are the most expensive.

 

[Tasmaniak]

ASa side note, the LEDs for the Display will need to be mounted on their side.