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  #1  
Old 01-11-2019, 11:28 AM
iamtheari iamtheari is offline
 
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Default Selectively Latching Momentary Switch Circuit

This is for my smoke system. I plan to have an enable/disable switch on the panel, but I want the on/off control on my stick. I have a flashlight that works how I want it to work, but my one semester of EE courses in college didn't cover this.

The flashlight has one momentary button. When you tap it briefly, it latches the light ON. Tap it again to turn the light OFF. But if you hold the button down for more than about a half second, it just shines the light until you release the button.

I don't want to disassemble this particular flashlight to try to figure out the circuit. Does anyone have ideas on how to wire such a thing up without needing a microcontroller? I can make a latching circuit easily enough, but the dual function is beyond me.
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Old 01-11-2019, 12:01 PM
lr172 lr172 is online now
 
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Your flashlight does that through digital processing/logic using only a momentary switch. Not sure how you can replicate that for your application.

Larry
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Old 01-12-2019, 06:04 AM
Mich48041 Mich48041 is offline
 
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Someone on the AeroElectric List might be able to design a circuit for you.
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  #4  
Old 01-12-2019, 08:02 AM
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Quote:
Originally Posted by lr172 View Post
Your flashlight does that through digital processing/logic using only a momentary switch. Not sure how you can replicate that for your application.

Larry
What Larry said. Its done with a freq clock and a counter. Its digital logic. We didnt do digital circuits until second year EE...tho in reality I didnt learn proper digital design until I went to work doing it. However, if you built it it would have to be out of discrete components and it would be bulky, and probably suseptable to stray static electricity; not what you want for your smoke system - the flashlight guys built the functions into a chip they designed and sent out for fab, MOSAIC style.....if they even use that anymore.
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Old 01-12-2019, 08:18 AM
iamtheari iamtheari is offline
 
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Quote:
Originally Posted by maniago View Post
What Larry said. Its done with a freq clock and a counter. Its digital logic. We didnt do digital circuits until second year EE...tho in reality I didnt learn proper digital design until I went to work doing it. However, if you built it it would have to be out of discrete components and it would be bulky, and probably suseptable to stray static electricity; not what you want for your smoke system - the flashlight guys built the functions into a chip they designed and sent out for fab, MOSAIC style.....if they even use that anymore.
That makes sense to me, that they would design a chip for their flashlights and have it mass-produced. It's a shame that Vertical Power won't let us reprogram the VP-X firmware to do things like this. Of course, that's one of those "what could possibly go wrong?" ideas that is better left on the drawing board.
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Old 01-12-2019, 08:53 AM
rv7charlie rv7charlie is offline
 
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I'd try to give a bit more thought to how it would operate while you're actually flying, before pursuing implementation. A pushbutton with no physical feedback of its condition leaves you without knowledge of its state. If it's a light in front of your eyes, great (maybe). But if its smoke out the back of the plane....

I'd find it easier to use a toggle or rocker switch that was center-off, momentary on in one direction and latching on in the other.

Just another perspective, FWIW.

Charlie
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  #7  
Old 01-12-2019, 11:58 AM
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fl-mike fl-mike is offline
 
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I think with some thought it could be done with some resistors, capacitors and a D flip flop or two. However, I think you are over complicating things unnecessarily. You would also need a logic power supply and drivers or relay to control the system.
Consider a mom-off-on toggle switch or slide switch. (On)-off-on.
A mini would fit on the stick.
KISS
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Old 01-12-2019, 12:28 PM
rocketman1988 rocketman1988 is offline
 
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Default arduino

An arduino (or clone) would be able to accomplish this with some basic coding...
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  #9  
Old 01-12-2019, 02:44 PM
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Quote:
Originally Posted by fl-mike View Post
...
Consider a mom-off-on toggle switch or slide switch. (On)-off-on.
A mini would fit on the stick.
KISS
Sometimes the simplest solution is the best...
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Last edited by az_gila : 01-12-2019 at 11:45 PM.
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  #10  
Old 01-12-2019, 02:57 PM
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Mike S Mike S is offline
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Any chance of just lifting/transplanting the circuitry from the flashlight-----and using it to control some magic electronic widget capable of handling the current of the smoke system??
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