As shown for the general multi-function alarm and timing circuitry. The timing of the circuit can range from 5 minutes to 3 hours. Timing components C2, VD1 and VT1 composition
capacitance multiplier circuit 555. CK1 from the timing input socket ~ 9V DC voltage, and so the timing for radio work. K1 is set to the timing gear, press the AN, 555 feet high output (6 ~ 9V), while VT2 off. When the timer expires, the three 555 pin goes low, CK1 no voltage output, VT2 is turned on, the alarm circuit F1 and F2 generation of the alarm sound and light alarm 20 seconds and F3 to F5 generated. A, B-side can add a variety of additional sensors sound and light alarm circuit.