Hello all!
I'm working on a personal project and I am at my absolute whits end here. I have an N.O./N.C. switch (http://www.nteinc.com/switches/pdf/magnetic_alarm/alarm_01.pdf) so I'm not too concerned with which way I use it.
My goal is as follows:
When the two parts of the switch are separated from each other an LED strip turns on for 30 seconds and then turns off until the switch pieces are brought together again and then pulled apart again at which point it would then turn on for another 30 seconds...repeat indefinitely.
What I've tried:
I've calculated that I'll be using 1Mohm resistor and 22uF capacitor to generate a 24.2 second pulse (which is close enough to 30 for me right now). I've attempted to hook up the following circuits
http://www.electroschematics.com/wp-content/uploads/2010/11/555-timer-positive-trigger.jpg
http://forum.allaboutcircuits.com/attachments/ne555-power-on-one-shot-png.38684/
http://home.cogeco.ca/~rpaisley4/LM555Helpers2.GIF
http://www.doctronics.co.uk/555.htm#reset
http://www.doctronics.co.uk/Images_swf/555_07.swf
but they do not perform as expected and either only turn on/off the led strip by the switch without the timer or they run indefinitely.
I'm not entirely sure what I'm missing here but I would greatly appreciate an education as well as reference circuit. I think this has to be very common because it's almost like an intrusion alarm where if the window is opened an alarm sounds for a period of time so I'm not sure why I'm unable to get this to behave the way I want to.
Thanks in advance! You'll be saving my sanity here, I've been at this all day.
Ray
I'm working on a personal project and I am at my absolute whits end here. I have an N.O./N.C. switch (http://www.nteinc.com/switches/pdf/magnetic_alarm/alarm_01.pdf) so I'm not too concerned with which way I use it.
My goal is as follows:
When the two parts of the switch are separated from each other an LED strip turns on for 30 seconds and then turns off until the switch pieces are brought together again and then pulled apart again at which point it would then turn on for another 30 seconds...repeat indefinitely.
What I've tried:
I've calculated that I'll be using 1Mohm resistor and 22uF capacitor to generate a 24.2 second pulse (which is close enough to 30 for me right now). I've attempted to hook up the following circuits
http://www.electroschematics.com/wp-content/uploads/2010/11/555-timer-positive-trigger.jpg
http://forum.allaboutcircuits.com/attachments/ne555-power-on-one-shot-png.38684/
http://home.cogeco.ca/~rpaisley4/LM555Helpers2.GIF
http://www.doctronics.co.uk/555.htm#reset
http://www.doctronics.co.uk/Images_swf/555_07.swf
but they do not perform as expected and either only turn on/off the led strip by the switch without the timer or they run indefinitely.
I'm not entirely sure what I'm missing here but I would greatly appreciate an education as well as reference circuit. I think this has to be very common because it's almost like an intrusion alarm where if the window is opened an alarm sounds for a period of time so I'm not sure why I'm unable to get this to behave the way I want to.
Thanks in advance! You'll be saving my sanity here, I've been at this all day.
Ray