LED to indicate off switch

Discussion in 'The Projects Forum' started by tee2, Nov 30, 2009.

  1. tee2

    Thread Starter Active Member

    Nov 19, 2004
    46
    3
    Hi,

    I have a project that I want to do this winter, but I'm ordering some part and would like to get whatever I would need for this too.

    I need to put a switch on my motorcycle to turn off the head light. When riding offroad at low RPM's the battery can run low to where the starter won't work. I would like to have an indicator LED that would be on when the headlight is off. Is there an easy way to do this. A bonus would be a bi-colored LED, red LED for off and green for on. The bike is 12V but I will have 5V from a USB outlet that is for the GPS.

    I did some searching on Google but am not to sure what to look for.

    Thanks
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    You can use a bi-color LED with three pins instead of two. Connect the common pin to 0V, find one that works that way and does not requires its common pin to V+. Then use a SPDT switch with its common contact connected to 12V and connect the other two pins of the LED to switch NC (red) and NO (green). Finally, use the NO contact of the switch to drive the headlight. Do not forget to use resistor to limit the current through the LED.
     
  3. tee2

    Thread Starter Active Member

    Nov 19, 2004
    46
    3
    Thanks for the reply, I looked for some bi-colored LEDs, but the problem with them is most are low MCD and can't be seen during the day (sunny). The brighter ones will blind you at night. After I thought about it I just need one LED to let me know when the headlight is off.

    Todd
     
Loading...