momentary (holding) on /off switch

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groggory

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I found this schematic for an on off holding switch that uses a momentary switch. But was wondering if you guys could think of a more elegant way of doing it. Show your expertise and surprise me :D

alt1.gif
 
This is the discussion on head-fi's forum on this particular application. Its a good read. Some people throw out some ideas on there worth noting.
 
Throw the momentary switch away, and get a POPO switch instead. (Push on, push off)

THis will save you from needing a voltage regulator for your logic gates, debounce circuitry, and depending on your applications, you might even be able to loose the transistor and relay as well.

HOw's that for elegance?;)
 
Yep. A simple push on/push off maintained switch would be the simplest solution. Sometimes old tech is still best. But i'm sure you aren't looking for practical, but geeking instead. ;) :D
 
The whole reason I'm working on this circuit is so I can use the same on/off switch as the guy here...

PPA1.jpg


Try and tell me that switch doesn't look badass.
 
You could use a J-K flipflop, with the switch hooked up to the clock pin. That circuit seems like it would work too. Why don't you want to use it?


Edit: As was mentioned on the other forums there, you could quite easily have a standby light if you did use the flipflop.
 
so.. when the button is pressed.. wave should look like this i'm guessing? just a pulse that lasts a certain amount of time?


Code: 
     ______
____|      |_____

for that you could use a Monostable Vibrator, which uses a common 555 timer, a few caps and a few resistors.

i can post schematics and formulas if you want me too?
 
Originally posted by plot
so.. when the button is pressed.. wave should look like this i'm guessing? just a pulse that lasts a certain amount of time?


Code: 
     ______
____|      |_____

for that you could use a Monostable Vibrator, which uses a common 555 timer, a few caps and a few resistors.

i can post schematics and formulas if you want me too?
Click to expand...

That sounds easy, and kind of what my EE teacher was talking about. Schematics would be very helpful. Thanks
 
Took me a few, but i whipped this up. Only limitation i can foresee is, might not be able to hold the signal high as long as you want it too.

monostable.PNG


Use an available cap, and calculate the resistance needed. I'm guessing you already have an idea of how long you want the pulse to stay high... so solve for R.

I should probably also mention that Pin 3 is the output :p
 
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