Letter box fun sound and light reporter circuit design

Photocoupler

When a letter or newspaper is put into the mailbox, the message box of the mailbox will automatically emit an audible and visual signal. The utterance statement "Thank you for coming!" is a greeting to the comrade who sent the mail, and informs the owner of the mail that the existing mail has been sent, please Read in time. It's convenient and fun.
The sound and light reporting circuit includes a light-controlled sensing switch, a monostable trigger, and an acousto-optic reporting circuit as shown. In the figure, D1 is an infrared light-emitting diode, and its current limiting resistor R1 is mounted on one side of the mailbox delivery port; VTl is a phototransistor 3DU series device placed on the other side of the delivery port. In normal times, the infrared light path is unimpeded. VT1 is in the on state and is low-resistance, so that the 2 pin of IC1 is high, and 555 is reset, and its 3 feet are low.
When there is mail in the mailbox, the mail will cut off the light path (that is, the moment when the letter is input) VT1 is turned off due to no light, and it is high resistance (several hundred kΩ or more). At this time, the 2 feet of 555 are low, making 555 Bits are high, which provides an operating voltage source for LEDL and IC2.
After the IC1 is triggered to turn to a high level, the LED illuminates and the IC2 emits a voice signal. IC2 uses the language integrated circuit KD-5604, which has the voice signal of “Thank you!”, when the power is added and triggered, the memory signal is immediately sent out, and the speaker is amplified by VT2, and the speaker is sent “Thank you!” . The typical operating voltage of the KD-5604 is 3V, so the R5 and DW regulator circuits are used in the circuit, and +3V is regulated as the operating voltage. The KI-5604 has two trigger terminals. When you turn on TRIG2, you can send "Welcome!", turn on TRIG2, and issue the "Thank you!" statement.