Guys,

I want to share my weekend experiment with PIR and RS485 on creating motion detector doorbell,
the idea is simple, communication between MCU and sensor....and that's it

Step 1: Prepare the Parts

Let's get started by preparing the parts
1. MCU module for sensor, I used ATMEGA128, because that's the PCB I have now, you can use any MCUs you like.
2. Receiver module, I made the same MCU for this module but with different PCB, bigger.
3. AVR programmer.
4. LCD 16x2
5. RS485 receiver and transmitter module
6. PIR module

Step 2: The Sofware

Guys,

The software is divided by two,
Transmitter and receiver,

It will read the sensor status and transmit the data if there's someone waiting in front of the door,
the receiver will give us a buzz with a tone and display on LCD.

That's it....future release will be the wireless version one, I have developed it but not yet stable...