[simpits-tech] Momentary on-off

[Brian Sikkema]

Sounds perfect! Like Gene said, a schematic would be awesome. :) But this definitely looks like it will do the trick.

And for my next trick - fitting it all into an old graphing calculator case! ;)

Brian
  ----- Original Message ----- 
  From: Jim Sturcbecher 
  To: Simulator Cockpit tech list 
  Sent: Wednesday, October 08, 2003 3:49 PM
  Subject: Re: [simpits-tech] Momentary on-off


  Recipe as follows:

  1 - Connect one side of the switch to ground.

  2 -  Add a pullup resistor to VCC on the other switch contact. this
        gives you a normally high output that goes to ground when the
        button is pushed.

  3 - Feed this signal via a RC network (series resistor, then cap to gnd)
       to lose the switch-bounce noise.

  4 - This then goes into a 74LS14 Schmitt trigger invertor.

  5 - You will now have a nice clean high-going signal out of the invertor
       when you push the button.

  6 - Feed this to the clock input of a D-Type flip-flop (74LS74) which has
       the /Q output connected back to the D input and both /SET and /CLR
       connected to VCC.

  7 - Now every time you press the button, the Q output of the flip-flop will
       change state.

  Voila, one change-over switch from a single push-button. You can drive
  the leds from the Q output through a transistor to take the current.

  Serve and enjoy.

  Jim.

  At 8-10-03 18:57, you wrote:

    Quick question:
     
    I need to make a momentary pushbutton switch turn some LEDs on and off. I.E. you push the button once, they turn on, you push it again, they turn off. Any ideas?
     
    Brian
     
    PS - I've been having trouble lately with my messages coming back from simpits-tech as undeliverable my first try. Anyone else having this?
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