I am trying to create an alarm system for a sliding gate for my college project. The idea is that when the gate is closed the circuit is broken but when the gate is opened the circuit is closed and after 45 seconds the alarm goes off.
So far I have worked out that I can use a normally closed reed switch so when the gate is closed the circuit breaks but when it opens the reed switch finishes the circuit. I can't think of a reason this wouldn't work but I have never been great at electronics so i might be wrong.
Assuming that works the problem I'm having is that with this set up the alarm will go off instantly and i want a 45 second delay. Any help/advice would be greatly appreciated.
So far I have worked out that I can use a normally closed reed switch so when the gate is closed the circuit breaks but when it opens the reed switch finishes the circuit. I can't think of a reason this wouldn't work but I have never been great at electronics so i might be wrong.
Assuming that works the problem I'm having is that with this set up the alarm will go off instantly and i want a 45 second delay. Any help/advice would be greatly appreciated.