Light following robot without using microcontroller

The main aim of the project is to build a light chaser robot that is capable
of detecting and following the light that falls on it.

Components required:

1 LDR Sensor x 2
2 DC Motor x 2
3 BC547 (NPN transistor) x 2
4 Battery 6v or greater(preferably 9v) x 1
5 Diode x 2

Image of the model:

Working :
The robot uses sensors the detect the light that falls on it, motors are
used to ensure locomotion. The circuit is designed in such a way that the
robot is able to change the direction and advance in the direction of light.
The best part of the project is the one does not have to use a
microcontroller, thus cutting down the expense compared to other
projects that use microcontroller.

Circuit diagram :
Light activated motor

Complete circuit diagram :

Working :
• The sensor on the right side is connected to the base of transistor
circuitry and then to the left wheel which ensures motion of the
robot towards right when the sensor is activated.
• Similarly, the sensor on the left side is connected to the right wheel
enabling the motion towards left.
• When both the sensors are equally illuminated, energises both the
wheels equally and thus moves in forward direction.
• Hence, the robot is capable of moving forward and at the same
time towards left or right base on illumination that the individual
sensors receive.

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