Most doorbells just make a simple generic tone. But I thought that it would be fun to modify a door bell so that it has a customizable ringtone. That way you can set it to play music or custom greetings. You could make it to scream on Halloween and play carols at Christmas. So in this project, I am going to share with you how to add a simple recording module to a wireless doorbell.
Step 1: Materials
Wireless Doorbell (and required batteries)
9V recording module (RadioShack Model: 276-1323)
9 volt battery
Soldering Iron and Solder (optional)
Hot glue and hot glue gun (optional)
Step 2: Background: How the Wireless Doorbell Receiver Works
1. The Radio Receiver: This section filters and amplifies the incoming radio signal.
2. The Decoder Array: This array of jumpers is used to set either the device's tuning frequency or the security code on the IC chip. This helps to prevent it from interfering with other nearby wireless devices.
3. The IC Chip: The IC Chip monitors the incoming signal and detects when the button on the transmitter has been pressed. When the signal is detected, it sends a tone to the speaker.
4. The Volume Control: This is a simple transistor amplifier that uses a variable resistor to set the speaker volume.
5. The Speaker: The speaker is a plain 0.25W speaker. It is wired between the positive supply voltage and the volume control transistor.