Ok my brother has a one of those car alarms that has the blinking blue light when it's active. What he wants to do is take like 4 or 5 other LEDs 4.5V ones and place then in the other corners of the car and have them pulse like the alarm one. So what i did is took my DMM to the one led that the alarm has and is a ~3v pluse. So we did an experment and tried to run that LED and one of the green one off that same wire at the same time and only the green one would blink. I came I belive the wire don't have the amps it needs to run both let alone 4 . So i figure that i can probable use a relay and a transister or something like that to switch a 12V line in the car on and off to run the LEDs but i have no clue what transisters, relay etc... or reallt how to hook them up. Ant info would be nice .
Use an optoisolator, it's better than a relay. A relay won't last long if it's turning on and off every time and you'll get the "click" sound from it which is going to be annoying.
No, the 2.1V green was effectively bypassing the 3.5V blue - the blue was only getting 2.1V across its leads, not enough to light it. Mixing different colours, each led needs its own series resistor. But don't try running more leds without a current-boost transistor, you'll likely burn out the existing led driver.
hummmmm Well for one thing the green one is 4.5V i don't know what the Blue one is. second eather i don't understand you or i did a bad job explaining what we did. There is the little box that has the LED in it that sits on the dash. It has a power and ground running to it. What we did is we ran the Green LED off the taped up part of thoses two wires from when it got cought in the door. So in essince we took the wire going to the box with the Blue LED cut that put in the Green, then let the wire continue to the box with the Blue one which wouldn't light up as long as the green one was in place.
