One can get push button switches that latch on when pushed/latch off
when pushed again. IF you want just digital mode while switch is
pressed then no problem. If you want to make sure the radio stays in
analog until commanded requiring the op to hold during digital then a
momentary switch can be used.
A "flip flop" or D-Type latch like the 74LS74, a 30 years old part, can
be made to work, but unless you are driving with some electronics to
automatically change between digita/analog it would be over kill. Also
sounds like the latch is still going to a switch to flip the flip-flop
and with switch bounce one would need a de-bounce circuit. A 74LS123
one shot is good for this. However, still over kill. We could also do
with a CPU like the PIC processors, etc. Fun to work with and would
learn something, but WAY OVER KILL, hi.
A switch is easy no brainer here unless there are othe issues. Requires
no power, just some wiring and about every type and size of switch one
can imagine is on the market.
73, ron, n9ee/r
On Sun, May 11, 2008 at 8:22 PM, Rich Summers wrote:
I can't use a toggle switch because the contact to
enable the scramble board needs to be momentary to
turn on the board and then a momentary contact to
switch off the board. This contact will be using an
enable wire from the board and another wire that is a
ground. I think a flip flop MAY be the way to go. I
was also wondering if there is a push button switch
that has 2 spst contacts?
Thanks.
--- MCH < [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > wrote:
For that matter, why not just a toggle switch?
Joe M.
Rich Summers wrote:
I need to build a simple circuit to enable a voice
scrambler in a radio.
What I need is a momentary contact by pressing a
button so that the
activation lead goes to ground and when this
happens I need an led
indication that the unit has been activated. I also need the led to
turn off when the button is
pressed again. This
deactivates the board and the radio returns to
normal mode.
I need this in a small box. Does anyone have a circuit I could build
for this
particular application?
Thanks,
Rich
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