The 555 adjustable timer circuit ... green LED turns OFF, the red LED turns ON and the beeper sounds. The time period is set by adjusting the variable resistor. It can be adjusted from 1 to 10 minutes ...

This simple alarm timer ... led does not does not affect the operation of the circuit and was included only to show that it works. So, R3 and D1 are optional components. S1 can be a tilt-sensitive ...