It uses just about any comparator (LM324, 339, etc.) and any SPST switch that operates with the opening and closing of your door.
When the door is closed, the closed switch allows the capacitor in the positive input of the comparator to charge and hold. When the door is opened, voltage is cut off from the cap, and it begins to discharge. When the + input voltage falls below that of the - input, the comparator turns on and activates the buzzer.
The R*C combination can be adjusted to allow a desired delay time.
If the door is closed before the comparator is activated, voltage is reapplied to the cap and nothing happens.
The attached schematic is a bare bones idea to go by, if you are interested.
Can anyone help me with a circuit diagram for my requirement? My requirement is I need to switch ON a motor (6V -DC) for 2 - 3 seconds every 14 days. The rest of the time the motor is OFF.
Can anyone help me with a circuit diagram for my requirement? My requirement is I need to switch ON a motor (6V -DC) for 2 - 3 seconds every 14 days. The rest of the time the motor is OFF.
You need to apply a trigger signal to a monostable circuit on every 2 weeks.2 weeks period is pretty higher.Easiest way is to use a RTC with a micro controller with lots of battery backup.