Wireless Video Surveillance Robot using Raspberry Pi

By Hemang Pandhi

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Component list

Device Name Quantity
Raspberry Pi 2 1
Power Bank (5V) 1

 

Sd card (8GB) 1
RF-Module (Tx-Rx- Pair) 1
HT12E 1
HT12D 1
Battery (12V-1.2A) 1
Robot Chassis 1
Wheel 4
Motor (12V-200RPM) 2
L293D 1
Switches On-off 4
Cell Battery (1.5V) 2
USB Wi-Fi Adapter (Edimax) 1
IR Sensor (Pair) 2
Motion Sensor 1
Raspberry pi Camera 1
Connectors Required as per implementation

Circuit description

This video surveillance robot is controlling by two possible ways
• Robot movement control by wireless Remote (within 100m distance).
• Robot movement control by web browser from anywhere.

The circuit is divided into transmitter and receiver sections. The transmitter section consists of an RF Transmitter, HT12E encoder IC and four push buttons.

Transmitter

Figure 4 Circuit Diagram of Remote
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The circuit shown in fig operates using 1.5V(3 cell).HT12E is an encoder IC that converts the 4-bit parallel data from the 4 data pins into serial data in order to transmit over RF link using the transmitter. A 680 KΩ resistor is connected between the oscillator terminals of encoder IC. This is to enable the oscillator.

There are four switches is connected with HT12-E IC which will be used to control the movement of the robot.

We have connected all address to ground on both transmitter and receiver side.
Pin 17 of HT12E is directly connected to the data pin of RF-Tx, so RF-Tx will radiate signal which has information of input status. The receiver will collect the signal and decode it.

Main Circuit

Figure 5: Circuit diagram of robot

The circuit shown in fig operate using power bank. A Raspberry Pi required 5V supply which is provided through power bank. The receiver section consists of RF Receiver, HT12D Decoder IC. An extra LED is connected to VT (Valid Transmission) pin of the decoder IC. This is used to indicate a successful transmission of data. Similarly, a 33 KΩ resistor is connected to the oscillator pins of decoder IC.

As well as we are proving output of HT12D (data pin) to raspberry pi so Raspberry Pi will decide the direction of the robot. We have attached two IR sensors with the robot which can detect the object if any object detected then the robot will stop and turn right/turn left according to distance/position of an object.

We have used an L293D motor driving circuit to control the motor movement because the output of the raspberry pies nowhere strong enough to drive dc motor directly. This is a very useful chip. It can control two motors independently. We can also control the speed of the motor using PWM output. But in raspberry pi, we have only one PWM channel so we can control only one motor speed.

The L293D has two +V pins (8 and 16). The pin ‘+Vmotor (8) provides the power for the motors, and +V (16) for the chip’s logic. We have connected pin 16 to the 5V pin of the Pi and pin 8 to a battery pack.

Enable A B Result
HIGH High Low Forward
HIGH Low High Backward
HIGH High High Stop
HIGH Low Low Stop

You can see the truth table to understand more about direction controlling of robot.

Robot controlled from Internet

In order to control the robot from Internet, we have written a python script which will read web link continuously, and do necessary movement according to the input received from the web link. We are using 6 Tab in our GUI (Graphical User Interface) forward, backward, right, left, stop and camera.

When the user gives a particular input from the webpage, it will be stored in a text file on the server, at the robot end python script is running continuously which will read that text file and make movement decision according to user input. Raspberry pi will give output to L293D which will be used for controlling direction of motor according to received input from Raspberry pi.

Hence when the user clicks on the forward button, the robot will move in the forward direction and website will redirect to the index.html page so that user can give another command. Let’s say if the user hits the right button, in this case, only one motor (back-left motor) will be enabled and the robot will move in the right direction.

In order to turn on camera user will have to click on Turn On button provided in GUI. Once camera gets turned on, user able to see the front view from robot by pressing the camera button. The user can see the front view of the camera from anywhere just user need to have connected to the internet.

We have implemented a python script which turned on camera automatically when the object is detected by IR sensor.

Application & Advantages

1) This can be used as a spy robot.
2) This robot has military application

Steps to run the project

We have to follow below steps to run the project.

• Provide supply from power bank to raspberry pi.
• When it gets booted up, we get GUI window once get GUI open terminal and execute following python script in order to control the robot from the wireless remote.
sudo python remote1.pyOpen web browser and type http://localhost/
• Once we get GUI for robot controlling click on forward.
• That’s it robot should move in forward direction. Same for other commands.
• In order to see front view of camera, user has to turn on the camera by pressing Turn On button from GUI after that user needs to press camera button.
• In order to control robot from webpage / Internet execute following python script.
sudo python rasbpi.py

Figure 6: Actual Implementation of System

Application

  • At the time of war where it can be used to collect information from the enemy terrain and monitor that information at a far secure area, and safely devise a plan for the counter attack.
  • Tracking locations of terrorist organizations and then plan an attack at a suitable time.
  • Making video surveillance of any disaster affected area where human beings can’t go.

Feel interested? Check out these Raspberry Pi projects.

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