LEDs and resistors
 

I thought I saw a post here about adding a resistor to a LED in order to make it "flash", but I can't seem to find it.

Here's what I want to do. I did the sidemarker mod so that they come one when I turn on my headlights. They also flash along with the turn signals. The 194 bulbs that I used though run really hot - so hot that one of the side marker housing is starting to melt.

If I were to replace the 194 bulb with the appropriate LED, do I need to add a resistor? If so, what value of resistor?

http://www.superbrightleds.com/specs/bulb_specs.htm

TIA

I can give you a simple circuit that will make a light blink if you want a project.
However, it's a ton easier just to buy a blinking LED. They're pretty commonly available.

The light already blinks according to the mod I did. But what I'm wondering is if I just replace the incandescent bulb with a LED bulb, will it still flash? If not, what will happen to the LED bulb?

gotchya, and I followed the link you supplied.

Yes, the LED will blink. And the bulbs you linked to have an operating voltage from 9-15V. So they are PNP, nothing else required.

Ben

Now that even I can understand. Thanks. :)

When one of my friends replaced his tail lights with LED ones like that they created a tiny circle of light that you almost couldn't see in the day time. And at night they just lit up in a small dot. They were BRIGHT but the tail light didnt light up, just that small dot in the center.

Do all LED setups work that way or is there a plastic bulb you can fit over it to disperse the light? I remember reading about some really bright and large LED on a different site, would that help? I would love to convert my car to full LED lighting, but I'm afraid of it looking like his did.

LEDs are very directional... conventional bulbs are omnidirectional. the reflectors are designed to maximize the light output behind the car by bending the light that is emitted everywhere else back to the rear of the car.

if the LED is only facing rearward, you basically lose the rest of the "spherical" light output from the back of the bulb. Not sure if anyone makes that...

Just some quick ideas based on the unidirectional info.

1. Placing a reflector infront of the LED and bounce it backwards on the lens.
Like the headlights on newer cars.

2. Build your own bulb and rather than facing strait out of the socket bend
the legs so they form a "halo" of sorts. Or maybe bend them 180 degrees
to use the lens?

3. Cut pieces of clear plastic and put the LED's in the edge of it to light up
the edge. You'd need a bunch of sheets statcked on eachother.

Would either of those be a good solution? I think the halo design would be easiest, not really changing anything just bending them. I think I like the plastic sheet idea the best though, that would look awsome.

Checkout superbrightLED.com. They have LEDs that are multi-directional just for that reason.