LED Circuit With Latching Switches Help Please

Discussion in 'The Projects Forum' started by GroundZero, Aug 12, 2011.

  1. GroundZero

    Thread Starter New Member

    Jul 30, 2011
    Hello All,

    I am new to this board and say greetings to everyone.

    What I am trying to create or actually get lots of help in creating is a circuit that will allow me to change LED status on a three button footswitch that has latching switches. This unit will be used with a guitar amplifier.

    Before anyone says use a DPDT switch and add a battery let me explain my dilemma and at the same time why that method will not work.

    There are 3 channels and upon turning the amp on it always defaults to channel 1. When you depress the channel 2 switch once the amp goes to channel 2, when you step on the channel 3 switch once the amp goes to channel 3 and if you want to go back to say channel 1 you just depress that switch again once. All of this is accomplished with one press of the corresponding latching switch.

    This is what happens when you install LED's using the DPDT switch.

    You are on channel 1 and the LED lights, then you switch to channel 2 and the LED lights, channel 3 and the LED lights. Now all of the LED's are illuminated so, when you want to switch back to another channel the LED then turns off and the amp does exactly what it is supposed to do, switch channels. So before you know it everything is confused and you can't remember what state that channel was in last time you pressed the switch. It could be on or it could be off, you have a 50% chance on being right anyway.

    So what I need is a circuit that will allow LED's to show the status of these 3 latching switches and bounce back and forth between them.

    Step on channel 1 switch LED lights,
    Step on channel 2 LED lights and cancels LED 1
    Step on channel 3 LED lights and cancels LED 2 etc
    Be powered by a 9 volt source.

    I figured out how to make a circuit for my other footswitch with momentary switches. Finding information for that was like child's play compared to this topic. I am not an electronics guru by any means and would appreciate any help with this! Thank you.

  2. SgtWookie


    Jul 17, 2007
    Here's one way to do it - not exactly simple, but that's about as simple as I could get it.


    This depends on your switch contacts being 0v or disconnected when not selected, and connected to +9v when closed for at least a moment. It could be modified to work if the switch is normally +9v, and 0v when selected - but that would take another few transistors and resistors.