Rich,
Now you are talking about some power for the light. Best use an LED
that draws low current, 5 ma.
Not knowing what you are connecting to, it might have enough current to
drive the LED.
Are you simply grounding an input, appling power to an input, etc. Do
you have details of what you are connecting to???
73, ron, n9ee/r
Ron Wright, N9EE
727-376-6575
MICRO COMPUTER CONCEPTS
Owner 146.64 repeater Tampa Bay, FL
No tone, all are welcome.
On Mon, May 12, 2008 at 2:29 PM, Rich Summers wrote:
Ron...That is exactly what I could use as long as it
had some type of light to let the person know that the
board has been enabled.
Rich
--- Ron Wright < [EMAIL PROTECTED] net <mailto:[EMAIL PROTECTED]> >
wrote:
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]> <mailto: [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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