DIY Kit Ding dong doorbell

NE555 doorbell information

Feature:

Dingdong doorbell switch s1 is a button switch on the door, no need to press the switch, the capacitor cannot be connected and no longer charged, and the capacitor voltage is 0 v, the reset is already in a low level state, causing the speaker to not work, when the switch s1 is turned off, the VCC current The capacitor is charged through the diode, so that the voltage across its terminals and the reset voltage also begin to rise gradually. When the capacitance of the capacitor rises to a higher level, that is, the reset input port is high, the timer starts, which consists of resistor, capacitor, and diode oscillator start-up work, and the output frequency is f1. When the switch s1 is turned off, the resistor and When the capacitor circuit is opened, the capacitor begins to discharge. At the same time by the resistance, capacitance and diode oscillator start work, the output frequency is "2 f". When the capacitor discharge ends, the reset low level resets and the timer stops working.

When the speaker output is terminated, the output current causes the speaker to produce sound. The output frequencies are not at the same time, and the sound is different. The circuit has two different frequencies, so the speaker will make two different sounds, "ding" and "dong".

Product Specifications:

Package name: NE555 doorbell kit

Working voltage: 4.0-7.0V

PCB size: 28mm(L)*25mm(W)

Kit speaker: 8 ohms 0.25W

Color: Beige

Net weight: 15g

Package Included:

1*8 ohm 0.25W speaker

2*100MM red wire