Forgotten money alarm circuit

In buses and taxis, it often happens that passengers forget their money and belongings. This circuit can prompt when getting off the bus and issue a verbal alarm sound of "Please take your
money and belongings " to prevent passengers from forgetting their money and belongings on the bus. .
    (1) Circuit composition The circuit of the relic reminder is composed of a power circuit, a trigger control circuit and a voice circuit, as shown in the figure.
    The power circuit consists of battery GB, diode VD1, filter capacitors cz, c', G and voltage stabilizing integrated circuit IC 1.
    The trigger control circuit consists of door switch S1, door light HL, diode VD2, and resistors Ri~R3. Capacitor Ci. It consists of transistor rri, VT2
and optocoupler VLC.
    · j'
    voice circuit consists of microphone BM, recording switch S2, voice integrated circuit IC2, capacitors G, G. Resistor R, is
composed of speaker BL.
    (2) Circuit principle: After the +12V voltage is isolated and filtered by VD1, one channel is added to the positive electrode of the internal light-emitting diode of VLC through R3 and
the other channel is regulated to +5v by IC1 and supplied to IC2.
    After the passengers get on the bus, the door is closed, the door switch Sl is in the off state, the door light EL does not light up, VT1 and VT2 are cut off, VLC is in the off
state, IC2 does not work, and BL does not sound.
    When the passengers get off the car, the door opens and sl is turned on. EL lights up. VT1 and VT2 are turned on. The LED light-emitting diode lights up, the photosensitive transistor
is turned on, and IC 2 is triggered to work and drive the speaker IX. Send out verbal prompts (such as "Please bring your money and belongings", etc.) to remind
passengers in time not to forget money and belongings in the car.
    S2 is the recording switch . Turn it on to record the BM.