Spy-Bot: Wi-Fi Controlled Robotic Car

The development of a robotic car plays a vital role in many areas. The main aim of the proposed system is to design a Wi-Fi controlled robotic car (spy-bot) that can be used for surveillance applications. A complete description of the block diagram, the flow chart, and the working of the proposed system are discussed in the following sections.

Block Diagram of Wi-Fi Controlled Robotic Car

A I2v lithium-ion battery supplies power to the spy-bot. The spy-bot has three main sections:

  • 1. Webpage development (HTML script)
  • 2. Windows 10 Azure cloud platform
  • 3. Moving the robotic car

The Raspberry Pi acts as the brain behind the spy-bot. After the Raspberry Pi (Raspbian OS boots) is initialized, it waits for input commands from the webpage. The authenticated user controls the various movements of the spy-bot by issuing various commands through a webpage to the Raspberry Pi. All the commands (Left/Right/Forward/ Backward/Stop) are issued wirelessly through Wi-Fi, which is based on the IEEE 802.11 family.

Geared DC motors are used to direct the movement of the spy-bot. Four DC motors are used in the proposed system to control the different directions, such as left, right, forward, and stop. DC motors cannot be interfaced directly with the Raspberry PI, due to a mismatch in the current and voltage ratings. So, we require motor driver ICs to drive the DC motors. The L298N motor driver IC [28] is a motor driver IC that drives the DC motor with respect to the commands issued by the Raspberry Pi. In our prototype, we require two motor driver ICs. With the help of two driver ICs, we can control four DC motors, as shown in Figure 3.7. The Raspberry Pi directs the user commands from the webpage to control the required set of motors, which directs the movement of the surveillance bot.

The spy-bot has four digital cameras, with built-in Complementary Metal Oxide Semiconductor (CMOS) sensors. CMOS technology has the great advantages of blooming and smear performance. Choosing the right camera for our application is also a challenging task, because cameras capture a lot of real-time pictures and also stream live videos for surveillance systems. In the proposed system four digital

Overall block diagram of the proposed system

FIGURE 3.7 Overall block diagram of the proposed system.

cameras are used, to capture images in all directions, a most efficient way to capture images with a 360° view. The captured videos or images are stored in a secure cloud platform, for retrieval whenever needed for an investigation.

Major Components Used

The following are the various hardware and software components that have been used in the proposed system:

Raspberry Pi 2

  • 2. Digital web camera with CMOS sensors
  • 3. Geared DC motors
  • 4. Dual full-bridge L298N motor driver ICs
  • 5. Ultrasonic sensor
  • 6. Microsoft Azure cloud 3.3.3 Raspberry Pi 2

The proposed system uses Raspberry Pi 2. Raspberry Pi 2 has attractive features, such as a 900 MHz clock speed, four USB ports, 1 GB RAM, a camera interface connector (CSI), etc.

One of the most promising features for system reliability is the clock speed. Table 3.1 compares various versions of the Raspberry Pi, based on their clock speed, RAM memory, the processor used, and the USB ports. Raspberry Pi 2 does better when compared to the other versions. Raspberry Pi 2 promises 900 MHz processing speed, which is faster than the other Pis and makes the system work more reliably in real time [27]. Furthermore, the Pi 2 also has three additional USB ports when compared with the other Pis. This is very important, because we have to connect four digital webcams to the Raspberry Pi, which requires four USB ports. Hence, most interestingly, among the various versions, the Raspberry Pi 2 is preferred for our wireless surveillance system.

TABLE 3.1

Comparison of Raspberry Pi Versions

Raspberry Pi 2

Raspberry Pi A+

Raspberry Pi В

Processor

Broadcom BCM2836- 32bit ARM v7 Processor

Broadcom BCM2835- 32 bit ARM1176JZF-S Processor

Broadcom BCM2835- 32 bit ARM1176JZF-S Processor

Processor Speed

900 MHz

700 MHz

700 MHz

RAM

1 GB

256 MB

512 MB

USB Ports

4

1

2 x USB 2.0

Digital Web Camera

A driverless PC webcam with 5.0 mega pixels, USB 2.0, and microphone is used. Four digital web cams that stream videos or images in real time are interfaced with the Pi through the USB slots. The camera can be used in such a way that whenever an image or video is captured, it can be either viewed or stored in the computer. It can also be sent to the other users, via internet, in the form of mail. These captured videos or images can also be stored in the cloud for future reference. This also has a microphone that can be used to capture videos with sound. It has a special feature for face detection that is used to detect human faces in order to offer sharp focus automatically. These computerized web cameras can be utilized for security reconnaissance, PC vision, video broadcasting, and recording social videos.

Thus, these digital web cameras are very compatible for the proposed system, in terms of picture or video quality, memory, etc. In the proposed system, four digital web cameras are used to capture the surrounding images.

Geared DC Motor

A high-quality, low-cost 100 RPM Center Shaft Economy Series DC geared motor is used in the proposed system. This geared DC motor has a long lifetime, because it has metal gears and pinions. Despite the fact that the motor gives 100 RPM at 12 V, the motor turns smoothly from 4 V to 12 V and gives a wide scope of RPM and torque. For the proposed system, four DC motors are used in order to control four wheels in the robotic car. The course of the DC motor turn can be controlled by the user, by giving either a high or a low voltage to the GPIO pins of the Raspberry Pi, where the driver module L298N is connected. This L298N driver module is used to interface the DC motors with Raspberry Pi. The experimental conditions for the DC motor are described in Table 3.2.

Dual Full-Bridge L298N Driver

The L298N utilized is a dual full-bridge motor driver that permits controlling the speed and bearing of two DC motors at the same time. It has a high voltage and a high ebb and flows double full-connect drivers intended to acknowledge standard TTL logic levels and drive inductive loads, for example, relays, solenoids, DC, and stepping motors. These driver modules are utilized to interface the DC motor with the

TABLE 3.2

Control Pattern of DC motor

Input A

Input В

Motor Condition

0

0

Break or Stop

0

1

Anti-Clockwise Movement

1

0

Clockwise Movement

1

1

Break or Stop

Raspberry Pi, in light of the fact that the yield flow from the GPIO pins of the Raspberry Pi is insufficient to drive the motor. Thus, these driver modules are used, which can give an output current that is sufficient to drive a motor. For the proposed system, it is therefore enough to use two dual full-bridge L298N driver modules to drive the required four DC motors.

Ultrasonic Sensors

Ultrasonic sensors [20] are used to find the presence of any obstacle in the pathway that the robotic car explores. In the proposed system, only one ultrasonic sensor is used. This sensor finds the presence of the obstacle using ultrasonic signals. The ultrasonic sensors emit ultrasonic waves. When these waves hit any obstacle, it is reflected back. In this manner, the separation between the sensor and the obstruction is estimated. The estimation time is calculated between the discharge and the gathering of the ultrasonic waves.

Microsoft Azure (Windows Cloud Platform)

Gartner [21] predicts a 38 percent growth in the usage of cloud platforms in the coming years. Forty Clouds [21] reviewed the security abilities of the top five IaaS suppliers—Amazon Web Services (AWS), Google Cloud Platform (GCP), IBM Cloud, Rackspace, and Azure—with a particular spotlight on information and system security, as well as identity and access management (IAM). A comparison report is shown in Figure 3.8.

Comparison of various cloud platforms (AWS, Azure, Google Cloud, and IBM Cloud)

FIGURE 3.8 Comparison of various cloud platforms (AWS, Azure, Google Cloud, and IBM Cloud).

Microsoft’s Azure Blob Storage has topped Amazon’s S3 and Google Cloud Storage in a progression of benchmark tests performed by NAS and capacity organization Nasuni [22]. In their 2015 white paper [22], The State of Cloud Storage, Nasuni revealed that for the second year straight, Microsoft topped tests that measure usefulness, cost, and execution, as shown in Figure 3.9. Amazon took the second spot, and Google finished a distant third. Microsoft Azure is an open cloud administration verified stage. It bolsters a wide assortment of working frameworks, programming dialects, and gadgets. It can go about as work back-closes for Windows, iOS, and Android-bolstered gadgets. One of the top motivations to utilize Azure for the proposed framework is to exploit its broad range of security instruments and abilities. Additionally, it offers the capacity to control them to modify security to meet what is needed to design an application. These devices and capacities help make it conceivable to make secure arrangements on the protected Azure stage. Microsoft Azure gives secrecy, trustworthiness, and accessibility to client information, while empowering the responsibility of the client.

For this very reason, Microsoft Azure is used in the proposed system, because it is very important that the images and videos captured be stored in a secure environment, since they are often used for surveillance purposes. Thus, Microsoft Azure acts as the best cloud platform, in terms of system security.

 
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