The ic has an in built circuitry to produce ding dong sound each time its pin 3 is pulled low. This is an easy to make electronic doorbell circuit.
Hacker S Bench Wireless Doorbell Hacking
Simple doorbell circuit diagram. The sound output from the ic cant however drive a speaker directly as this puts strain on the device. The s1 is open the circuit act as a two way doorbell. The battery is the weakest link here and should be the first place to look for trouble. This is very simple project it requires very less component and then its make it easy and simple but interesting project. 15v to 45v dc supply required for operation of this multi tone generator circuit. There are two switches s2 and s3 for front and rear door respectively.
The sound is stored in the ic as bits as in a rom. As illustrated in the above diagram the parts of an old doorbell circuit include. The bell a button mounted at the door and a battery somewhere in between the two. The working principal of the circuit doorbell is simple. The bc547 transistor along with the associated preset and the 100uf capacitor form a simple delay off timer circuit where the preset and the capacitor determines the delay for which the sound output may be sustained once the indicated push button is pressed. The diagram above depicts the proposed musical door bell circuit the various stages may be understood with the following explanation.
No any ic is used in this circuit. Connects all components as given in circuit diagram. At first when power is on to circuit then switch remain off when any touch the touch plate then transistor q1 triggered and as q1 get on the transistor q2 is also turned on. This automatic touch doorbell alarm switch is very sensitive with human finger and this is very simple to construct. This simple and cost effective ding dong electronic doorbell circuit is based on ic 8021 2. Fortunately its likely a simple matter to get things back in working order.
In this case circuit act as a two way doorbell with memory that is the audio alarm indicates whether the visitor is calling from the front door or from back door. Simple doorbell circuit diagram and schematic using um 66 ic which is a music sound generator.
Gallery of Simple Doorbell Circuit Diagram
