LED gauges

[McSparky]

My land rovers speedometer/odometer gauge was in need of some TLC; the odometer had never worked since I bought the truck and the speedo was in need of a calibration since fitting 7.50R16 tires (I'll put this in a separate post). Also, all the bulbs had blown and after finding it difficult to find 12v screw-in replacement bulbs (small town) I thought I would upgrade all the bulbs to LED instead. It's very easy to do, they should last much longer and they are much brighter than standard bulbs.

So to begin you will need:

>All the dead bulbs, or buy some cheap ones that have the same screw fitting, voltage doesn't matter since we're going to butcher them anyway.

>Some LED's. I used bright white ones (15000mcd brightness) rated at 3.7volts@30ma. You will also need some resistors to drop the ~13.8volts from the battery. Using ohms law (13.8v-3.7v)/30ma = ~337ohms. You can use 330ohms (orange-orange-brown).

Now, smash all the glass bulbs try not to damage the base and be careful because they tend to throw glass everywhere. wear eye protection and don't do it in your living room! Next, take some needle nose pliers and gently crush around the top of the base to break any glass still left and pull all the guts out. You should end up with something like this:

Trim the resistor leads, twist one side of the lead around the LED anode (usually the side with the longer leg). This is going inside the bulb base so measure it up first because you might have to trim the LED legs a bit.

Then solder and trim the loose lead on the resistor fairly short. You can make it shorter than this:

The bottom (+) of the bulb base is solder and should melt with a soldering iron so you need to push the free end of the resistor through, from the inside of the cup, while melting the base with your soldering iron. It need to just go through and don't push it too far through. then solder the free leg of the LED to the outside (or inside) of the bulb base.

Then to finish I just filled the base with some red silicon to stop things moving around.

And you're done! I was really pleased with the results

Here's a day shot:

And one at night:

The camera makes them look brighter than they are, but they are still plenty bright.

[RobotMan]

Nice job and well written up, thank you!

[Marco]

Very nice and useful conversion, I've made a link to this post @landroverweb.com

Cheers

Marco