Schematics For Delayed ON/OFF Switch??

[Paul]

I'd like to build up a switch that works identically to
the switch on my Nokia 6010 cell phone, which is
basically a membrane type button, which must be
depressed for about 2-3 seconds or so, before
the device is either turned ON or OFF.

I have seen schematics that use PIC chips with
delays, in conjunction with N-MOS and P-MOS
FETS, supposedly with low RdsOn, so that battery
efficiency is still good, and with decent leakage
while the device is OFF, in the tens of uAmps.

But I'm hoping someone out there has other
ideas for ultra-low voltage drops, and ultra-low
leakage current while the device is off, obviously
to extend battery life, but with the delayed reaction
so that accidental switching is minimized.

Thanks in advance.....

 

[MooseFET]

I'd like to build up a switch that works identically to
the switch on my Nokia 6010 cell phone, which is
basically a membrane type button, which must be
depressed for about 2-3 seconds or so, before
the device is either turned ON or OFF.

I have seen schematics that use PIC chips with
delays, in conjunction with N-MOS and P-MOS
FETS, supposedly with low RdsOn, so that battery
efficiency is still good, and with decent leakage
while the device is OFF, in the tens of uAmps.

But I'm hoping someone out there has other
ideas for ultra-low voltage drops, and ultra-low
leakage current while the device is off, obviously
to extend battery life, but with the delayed reaction
so that accidental switching is minimized.

Thanks in advance.....

When it is off and the button is not pressed, it doesn't need to take
any power at all. Basically the idea is like this:

semiconductor
Switch
--------+----------/o--------+--------- To load
! ! !
!o ! V
Button --! ! ---
!o-+--->!-------------+
! ! !
! -------------------
+--! Power Logic !
! -------------------
/
\
/ 1M
!
GND

The power logic is only powered on if the semiconductor switch is on
or is the button is pressed.


Another way to go is to make the power logic out of a CD4000 series IC
and leave the power on it.

The delay can be as simple as a RC circuit that is discharged any time
the button is not pressed. Like this:

----!<----
!\ ! !
Button in ---! >-------+---/\/\---+---+---
!/ !
buffer ===
!
GND

You can get CD4000 logic that has Schmit trigger inputs.

 

[Tam]

I'd like to build up a switch that works identically to
the switch on my Nokia 6010 cell phone, which is
basically a membrane type button, which must be
depressed for about 2-3 seconds or so, before
the device is either turned ON or OFF.

I have seen schematics that use PIC chips with
delays, in conjunction with N-MOS and P-MOS
FETS, supposedly with low RdsOn, so that battery
efficiency is still good, and with decent leakage
while the device is OFF, in the tens of uAmps.

But I'm hoping someone out there has other
ideas for ultra-low voltage drops, and ultra-low
leakage current while the device is off, obviously
to extend battery life, but with the delayed reaction
so that accidental switching is minimized.

Thanks in advance.....

The obvious way to me would be a push button and RC network going into a
Schmit trigger, driving a CMOS Dff. You can now make the turn on and turn
off times different, depending on the state of the FF. As a first
approximation 1S is 1 ufd and 1 meg.

Tam

 

[JeffM]

ASCII diagrams are a bit hard to read!

Not if you have the slightest clue, Google Grouper.
http://groups.google.com/group/sci....ginal+Fixed.text+Notepad+Proportional-*&fwc=1
918bbf53-c5a4-454c-90d8-3a566d034e3d@e10g2000prf.googlegroups.com

 

[Fred Bloggs]

But I'm hoping someone out there has other ideas for ultra-low
voltage drops, and ultra-low leakage current while the device is off,
obviously to extend battery life, but with the delayed reaction so
that accidental switching is minimized.

Hope is all you have apparently since anything even remotely approaching
analytical thinking is beyond your reach. That is a very confused
question full of superlatives, non sequiturs, and other problems:
"you've seen this (which does that) *but* you're hoping for that by not
using this."
Give us a break...

 

[Jim Thompson]

[snip]

Give us a break...

Yes, Fred, Please!

...Jim Thompson

 

[Paul]

�> But I'm hoping someone out there has other ideas for ultra-low
�> voltage drops, and ultra-low leakage current while the device is off,
�> obviously to extend battery life, but with the delayed reactionso
�> that accidental switching is minimized.

Hope is all you have apparently since anything even remotely approaching
analytical thinking is beyond your reach. That is a very confused
question full of superlatives, non sequiturs, and other problems:
"you've seen this (which does that) *but* you're hoping for that by not
using this."
Give us a break...

Reach for THIS, bone-head.

You have certainly dashed any
hopes I HAD.....