1. Elecbits

2. LFR
Description
LFR is a Robot that detects and follows a path using feedback mechanism.
The sensor used commonly for this are infrared (IR) sensor pair (transmitter and receiver) or photodiodes.
The sensor detects the black line using light reflection mechanism.
The change in the intensity thus instructs the micro-controller to control movements of the robot.
When photodiode is used the resistance is varied in accordance with the intensity of reflected light.

3. Block diagram

4. Working
Inbuilt Bluetooth of Android smartphone is used for connecting to Bluetooth module HC-05 of LFR.
Bluetooth module is used to receive the commands from smartphone.
IR sensors detects the line and give feedback to the micro-controller.
Two DC motors are used to control the movement of LFR.

5. Schematics
Picture
Pcb Desgins

6. Thank You