On Tue, 20 Nov 2012 05:15:02 -0800 (PST),
wrote:
Hi all,
I seem to recall from distant memory that it's possible to make a pulse detector out of two of transistors and a few resistors, but I can't find the circuit anywhere. Searches keep throwing up stuff about astable multivibrators and nand gates and that's not what I'm looking for.
Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v line. The pulse comes only after several days of inactivity and should turn an LED on permanently. No reset required and any subsequent pulses must *not* turn the LED off again, so it's operating like a bistable latch (if that's the right term).
Can anyone assist?
Tia.
[snip]
Along these lines, what would the group recommend for a weatherproof
switch to detect that a yard gate is not closed all the way?
...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice
480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at
http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.