automatic shopping trolley

1. Working of the project
The whole project can be divided into 4 sections: power section sensor,
section, control section and driver section.
Power section:
This section contains 12v battery, on-off switch, regulator IC. 12v battery
is used to supply the voltage to whole project. Motors, Relays and to
arduino which is the heart of the project is provided with 12v supply
voltage.
To switch on and off the battery a simple switch is used.
A simple on-off switch has one set of contacts, single pole, and one
switching position which conducts, single throw. This is type of switch is
called SPST (single pole, single throw) and its action is described as ON-
OFF. The switch mechanism has two positions: closed (on) and open
(off), but it is called 'single throw' because only one position conducts.
Sensors –IR sensor, color sensor buzzer required 5v supply.so there is a
regulator IC in arduino .it converts 12v to 5v.
Sensor section:
This section contains IR diodes, potentiometer, Comparator (Op-Amp)
and LED’s. Potentiometer is used for setting reference voltage at
comparator’s one terminal and IR sensors are used to sense the line and
provide a change in voltage at comparator’s second terminal. Then
comparator compares both voltages and generates a digital signal at
output. Here in this line follower circuit we have used comparator for ir
sensor. LM 358 is used as comparator. LM358 has inbuilt two low noise
Op-amps.
A trolley which follows a certain path controlled by a feedback mechanism
that follows a black line on white surface.
If an obstacle is found at less than 40cm the ultrasonic sensor measures
the distance and inform the arduino (microcontroller).the arduino then
switch off the motor. Then color sensor checks the color of the object
whether it is black or not. If it is black then buzzer will be on, until it is
picked and fill in the cart. If the color of the item is not black then the

2. trolley continues to move forward. When the line ends the ir sensor
senses the non-black path and it halts.
If the reverse simple switch is pressed the trolley try to move in reverse
direction and halts at the source where it is started.
Control Section:
Arduino Uno is used for controlling whole the process of project. The
outputs of ir sensor, ultrasonic sensor and color sensor are connected as
inputs of arduino. Arduino read these signals and send commands to
driver circuit to drive motors and buzzer which are connected as outputs
to arduino.
Driver section:
Driver sectionconsists relay and a d DC motors. Relays as Motor driver is
used for driving motors because arduino does not supply enough voltage
and current to motor. So we add a motor driver circuit to get enough
voltage and current for motor. Arduino sends commands to this motor
driver and then it drive motors.