I want a battery powered night light. Have found circuit diagrams for a couple circuits.
What I don't have is a way to switch Vcc off from entire circuit when 10 minute time is up (output goes low).
The circuit I like so far is one in which a switch applies Vcc to the circuit and a capacitor on pin 2 keeps trigger low so 555 fires. I just need a way to use a momentary push button switch to start Vcc flowing but have Vcc cut off when timer is done.
I don't want circuit using battery power for the 23 hours and 50 minutes the device is not in use.
I was thinking of using a switching transistor (2N2222 NPN) tied to output of 555. When push button is pressed, +Vcc is applied to base of NPN and output of 555. 555 fires and output is high keeping transistor conducting. Once output goes low, transistor cuts off and Vcc no longer flows through transistor.
Any ideas?
What I don't have is a way to switch Vcc off from entire circuit when 10 minute time is up (output goes low).
The circuit I like so far is one in which a switch applies Vcc to the circuit and a capacitor on pin 2 keeps trigger low so 555 fires. I just need a way to use a momentary push button switch to start Vcc flowing but have Vcc cut off when timer is done.
I don't want circuit using battery power for the 23 hours and 50 minutes the device is not in use.
I was thinking of using a switching transistor (2N2222 NPN) tied to output of 555. When push button is pressed, +Vcc is applied to base of NPN and output of 555. 555 fires and output is high keeping transistor conducting. Once output goes low, transistor cuts off and Vcc no longer flows through transistor.
Any ideas?