Greetings,
I have a refrigerator that is poorly designed and very, very easy to leave ajar. I want to build a battery operated 555 timer based circuit that will sound an alarm after a set time has passed with the door open. 555 circuits are easy enough to find, but I don't know what kind of switch set up to use.
The circuit will use a 9v battery, and current draw when off is a priority.
I want the switch in the closed position when the door is closed, so some electricity will be flowing through it. I want this amount of energy to be as low as possible.
Basically, I want a "High" signal of extremely low current to stop the 555 from charging.
How should I do this?
I have a refrigerator that is poorly designed and very, very easy to leave ajar. I want to build a battery operated 555 timer based circuit that will sound an alarm after a set time has passed with the door open. 555 circuits are easy enough to find, but I don't know what kind of switch set up to use.
The circuit will use a 9v battery, and current draw when off is a priority.
I want the switch in the closed position when the door is closed, so some electricity will be flowing through it. I want this amount of energy to be as low as possible.
Basically, I want a "High" signal of extremely low current to stop the 555 from charging.
How should I do this?