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Obstacle Avoiding Robot Without Microcontroller

Description

Contributor: 
Rachana Malviya, Technido

Obstacle avoidance is one of the most important aspects of mobile robotics. Without it robot movement would be very restrictive and fragile.

Obstacle Avoiding is a task which is used for detecting the objects placed in the path of your robot or any vehicle. So, to protect robot from any physical damages.

An obstacle avoiding robot is an intelligent device, which can automatically sense and overcome obstacles on its path. It is developed without micro-controller in order to eliminate critical circuits, difficult programming etc. All you want to do is to just understand the circuit diagram and start doing this robot. This simple technique can be incorporated in wheeled robots to keep them away from damages and accidents.

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Image: Obstacle Avoiding Robot

Obstacle Avoidance is a robotic discipline with the objective of moving vehicles on the basis of the sensorial information. The use of these methods front to classic methods (path planning) is a natural alternative when the scenario is dynamic with an unpredictable behavior. In these cases, the surroundings do not remain invariable, and thus the sensory information is used to detect the changes consequently adapting moving.

 

Block Diagram of Obstacle Avoiding Robot

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Explanation of block diagram

IR module  are used to avoid the obstacle if obstacle comes on the front of the IR module. Here 555 timer IC are used to generate the IR signal and TSOP (thin small outline package) are used to receive the IR signal.   

Stage 1

IR 555 Timer Section

555 is a very commonly used IC for generating accurate timing pulses. It is an 8 pin timer IC and has mainly two modes of operation monostable and astable. In monostable mode time delay of the pulses can be precisely controlled by an external resistor and a capacitor whereas in astable mode the frequency & duty cycle are controlled by two external resistors and a capacitor. 555 timer is very commonly used for generating time delays and pulses.

Pin Diagram of LM555 IC

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Pin Description:

 Pin No

 Function

 Name

1

Ground (0V)

Ground

2

Voltage below 1/3 Vcc to trigger the pulse

Trigger

3

Pulsating output

Output

4

Active low; interrupts the timing interval at Output

Reset

5

Provides access to the internal voltage divider; default 2/3 Vcc

Control Voltage

6

The pulse ends when the voltage is greater than Control

Threshold

7

Open collector output; to discharge the capacitor

Discharge

8

Supply voltage; 5V (4.5V - 16 V)

Vcc

LED:

LEDs are used as indicator lamps in many devices and are increasingly used for general lighting.

Long leg is positive.

Short leg is negative.

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IR Led:

An infrared light-emitting diode (LED) is a type of electronic device that emits infrared light not visible to the naked eye. An infrared LED operates like a regular LED, but may use different materials to produce infrared light.

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Stage 2

TSOP Receiver Section 

TSOP receiver section are used to receive the IR radiation coming from the IR led. TSOP have three pin  as given in the below diagram.

TSOP Receiver section

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Sr.No

Pin No

Pin Name

1

Pin 1

Gnd

2

Pin 2

Vs

3

Pin 3

out

Principal of operation

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How to IR sensor work

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It is the same principle in ALL Infra-Red proximity sensors. The basic idea is to send infra red light through IR-LEDs, which is then reflected by any object in front of the sensor.

One of the most useful sensor find its application while detecting object/hurdles, edges of surface etc. With a long range of 20 cm, TLL interface and ambient light protection makes it easy and reliable to use.
Features:       

·         Range: 20 cm

 

Motor Driving Stage

In this stage the motor driver l293D IC is used for to drive the motor. As the signal comes from the inverter IC it drives the motor according to signals comes.

L293D IC

L293D is a dual H-bridge motor driver integrated circuit (IC). Motor drivers act as current amplifiers since they take a low-current control signal and provide a higher-current signal. This higher current signal is used to drive the motors.

L293D contains two inbuilt H-bridge driver circuits. In its common mode of operation, two DC motors can be driven simultaneously, both in forward and reverse direction. The motor operations of two motors can be controlled by input logic at pins 2 & 7 and 10 & 15. Input logic 00 or 11 will stop the corresponding motor. Logic 01 and 10 will rotate it in clockwise and anticlockwise directions, respectively.

Enable pins 1 and 9 (corresponding to the two motors) must be high for motors to start operating. When an enable input is high, the associated driver gets enabled. As a result, the outputs become active and work in phase with their inputs. Similarly, when the enable input is low, that driver is disabled, and their outputs are off and in the high-impedance state.

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Truth table for robot Movement

Sr.No

IN1

IN2

IN3

IN4

Movement of robot

1

1

0

0

1

Forward

2

1

1

1

1

Stop

3

1

0

1

0

Left

4

0

1

0

1

Right

Accessories Required to make obstacle avoiding robot

Sr.No.

Component Name

Quantity

1.

Double AA batteries cell holder

1

2.

Chassis  ( Robotic  Platform)

1

3

Breadboard

1

4

Nipper

1

5.

Stripper

1

6.

One  core wire

As per the use

7.

Nose pliers

1

8

Screw driver

1

.

Comments (2)

Good attempt !!!

Good attempt !!!

can i use a l293b instead of

can i use a l293b instead of a l293d. also can i use a tsop1736 instead of a tsop1738

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