WIRELESS CONTROLLED ROBOTIC ARM
4. PROJECT DETAILS
4.1 DESIGN BACKGROUND
Our project is divided into two parts viz.
· User section
· Robot section
4.1.1 USER SECTION
This section is facilitated by the use of Joystick and buttons to control the robot. The position of Joystick determines the position of arm. On the movement of joystick, TX microcontroller sends the angular position of Joystick to the robot so that robot-side microcontroller could receive the angular position and command the servomotors to have desired position.
Major components of this section are:
· Potentiometer
· Keypad
· RF transmitter (XBee)
· Arduino board
· Monitor display
4.1.1.1 DESIGN OF JOYSTICK
Joystick to our project is an electromechanical device we designed using POT (Potentiometer) and fiber glass to control our Robotic arm. It consists of fiber glass plates assembled using grip and screw along with glue. Main component of this module is potentiometer.
FIGURE 4.1.1.1: JOYSTICK DESIGN
4.1.1.2 OPERATION
This joystick acts as a remote controller to the Robotic arm. Potentiometer is used to calculate the angular positions of joints of joystick. Joystick comprises a microcontroller module to analyze the angular data to control the robot section. Analog value from POT is fed to microcontroller module via analog pins and converted to 10bits long digital integer, which is then converted to angle in degree.
This angular value is transmitted to robot section using ISM band 2.4 GHz microwave using XBee RF module.
In our project angular value is transferred to robot section using ASCII codes (viz. 65>> A). Our project has two modes (viz. manual and Auto mode). Mode selection is done using push button in joystick. This mode change information is also sent to robot section via XBee RF module as ASCII char. Since both control signals and data are sent via same channel so, to prevent the ambiguity we figured out the solution. Solution is to create our own frame format to indicate that data has arrived not control signal.
Packet format:
@#<angle1><angle2><angle3><angle4><angle5><angle6>
Example of Packet Format: @#a4%6g!
4.1.2 ROBOT SECTION
This section is the main section of our project. Every desired operation is performed in this section, by the reception of signals transmitted from the user section. The wireless camera attached to this section continuously transmits the captured pictures to display on the monitor in user side. The DC motor and the Servomotor perform the movement as instructed from the user section. The main function of the Gripper is to grab the object and lift it up.
The robotic arm simulates the human arm in similar fashion as possible. Smoothness of the movement is dependent on how good is the user in using the joystick.
Major components of the part are:
· Arduino board
· PCB with complete circuitry
· Wireless camera
· RF receiver (XBee)
· Servomotors
· DC motors
· Caster wheel
· Wheels
· Led
· Motor driver IC (L293)
· Chassis (Plywood) and aluminum sheet
4.1.2.1 MECHANICAL DESIGNS
Mechanical part designs have been the toughest task while doing our project. Being from the electronics background we don’t have much knowledge about mechanical parts. We go through different websites, consulted people from mechanical background and we designed our mechanical parts as fallow as we feel appropriate according to the methods and components available to us. [5]
FIGURE 4.1.2.1 (a): DESIGN OF LOWER PART OF ARM
FIGURE 4.1.2.1 (b): DESIGN OF UPPER PART OF ARM
FIGURE 4.1.2.1 (c): DESIGN OF GRIPPER
4.2 METHODOLOGY
4.2.1 PROBLEM ANALYSIS
From ancient time human have been employed in areas where risk is maximum. Traditional method of solving problems were/are time consuming and error prone. So to achieve the maximum efficiency and reduce the risk in mankind we thought to build a movable robotic arm capable of doing human jobs. This solves the problem and also saves time and human effort.
4.2.2 RESEARCH AND TESTING
The technology used in our project is completely new to us so we obviously have got updated about new era of robotics and electronics. Different websites, worldwide and previous research papers was helpful to accomplish our project.
FIGURE 4.2.2 (a): TESTING IN ARDUINO MONITOR
FIGURE 4.2.2 (b): TESTING OF TRANSMISSION AND RECEPTION IN X-CTU
4.2.3 PROJECT SKETCHING AND MECHANICAL DESIGN
Since our project is electro-mechanical in nature, it needs proper sketching and designing in well-defined manner. Sketching gives the idea for cutting the frames out of the fiber glass-sheets. The chassis of the arm and body was made from fiber glass sheets. The arm consists of multiple joints on the basis of which the arm will operate.
4.2.4 SOFTWARE DEVELOPMENT AND SIMULATION
We have built our own control panel software for Windows and we will be operating the robot partially from computer and partially from joystick that we designed especially for our project. Firmware for the microcontroller was written in c and compiled in Arduino IDE. For simulation we used ISIS (Proteus).
FIGURE 4.2.4(a): SIMULATION OF ROBOT SIDE
FIGURE 4.2.4(b): SIMULATION OF USER SIDE (JOYSTICK)
4.2.5 CIRCUIT DESIGNING AND IMPLEMENTATION
The overall project needs electrical power and necessary circuit to function. So our next step was circuit designing. After successful simulation we have move forward towards circuit designing using software such as Eagle, PCB Wizard, ARIES, etc. to design PCB. The design is printed, pressed and etched. Circuit board was then drilled and components were soldered.
4.2.6 ASSEMBLY OF MODULES
Modules such as Robotic Arm, Robotic Base, Circuit Board, wireless transmitter, receiver, wireless camera, and Wires were assembled in well-functioning fashion.
4.3 COMPONENTS DESCRIPTION
For the completion of our project we have used the following components. Their description in details is as follows.
4.3.1 SERVO MOTOR
Servo refers to an error sensing feedback control which is used to correct the performance of a system. Servo or RC Servo Motors are DC motors equipped with a servo mechanism for precise control of angular position. The RC servo motors usually have a rotation limit from 90° to 180°. But servos do not rotate continually. Their rotation is restricted in between the fixed angles. The Servos are used for precision positioning. They are used in robotic arms and legs, sensor scanners and in RC toys like RC helicopter, airplanes and cars. [3]
Here in our system we have used seven servo motors for arm motion. In every corner of arm is handled by servomotor. Every movement of arm is handled by servomotor which is controlled by PWM from Arduino. Mechanical movement provides desired output for the system.
FIGURE 4.3.1: SERVO MOTOR
4.3.2 DC MOTOR
DC geared motor is an electric motor that uses electricity and a magnetic field to produce torque, which turns the motor. DC motors are intended to drive the robot body and the camera direction. Here DC motor is controlled by control panel. DC motors are arranged in such a way that both the robot body and camera can move in all four directions. Most DC motors are normally very easy to reverse; simply changing the polarity of DC input will reverse the direction of the drive shaft. This change over process can be achieved via a simple changeover switch or for remote or electronic control, via a suitable relay. Another big advantage of DC motors is that variable speed control is easy and can achieve with just a suitable variable resistor or variable power supply. For more precise control and maximum efficiency there is much other electronic PWM (Pulse Width Modulation) solution although these tend to have added complexity. Most DC motors are designed to exhibit the same speed and output torque in either the forward or reverse direction. Drive shaft speeds rpm (round per minute) are quoted with motor unloaded. [3]
FIGURE 4.3.2: DC MOTOR
4.3.3 ARDUINO BOARD
Arduino is an open source physical computing platform based on a simple input/output (I/O) board and a development environment that implements the Processing language. Arduino can be used to develop standalone interactive objects or can be connected to software on your computer (such as Flash, Processing, or Max/MSP). The boards can be assembled by hand or purchased preassembled; the open source IDE (Integrated Development Environment). [6]
arduino.jpg
FIGURE 4.3.3: ARDUINO BOARD
Some features of Arduino are:
Ø It is a multiplatform environment; it can run on Windows, Macintosh, and Linux.
Ø It is based on the Processing programming IDE, an easy-to-use development environment used by artists and designers.
Ø We program it via a USB cable, not a serial port. This feature is useful, because many modern computers don’t have serial ports.
Ø It is open source hardware and software.
Ø The Arduino Project was developed in an educational environment and is therefore great for newcomers to get things working quickly.
The Arduino board is a small microcontroller board, which is a small circuit (the board) that contains a whole computer on a small chip (the micro-controller).The Atmel atmega328 microcontroller is the heart of the Arduino board. [4]
Arduino board consists of 14 Digital IO pins (pins 0-13), 6 Analog In pins (pins 0-5), 6 Analog Out pins (pins 3, 5, 6,9,10 and 11).
4.3.4 XBEE PAIR (RF MODULE)
XBee is IEEE 802.15.4 standard RF module for wireless transmission and receiver. It is low cost, low power wireless sensor network operate within the ISM 2, 4 GHz frequency band. It can operate up to 90-100 meters to Trans-receive the signal. Data rate of this module for serial interface is 1200bps- 250kbps. Transmit power is 1mw (0dBm) and receiver sensitivity is -92dBm. The transmit peak current at 3.3V is 45mA and receiver current at 3.3V is 50mA.
Some features of XBee are:
§ Facilitated with 20pins
§ UART serial data transmission
§ Low power consumption
§ Easy to use with the help of X-CTU software
§ Serial interface Data rate: 1200bps- 250kbps
§ Operate in ISM 2.4GHz frequency band
§ Data integrity: Indoor (up to 30m) and outdoor (u)
It can function in two different operation mode viz. transparent mode and API (Application Programming Interface) mode. [7]
FIGURE 4.3.4: XBEE MODULE
4.3.5 MOTOR DRIVER IC L293
The L293 and L293D are quadruple high-current half-H drivers. The L293 is designed to provide bidirectional drive currents of up to 1 A at voltages from 4.5 V to 36 V. The L293D is designed to provide bidirectional drive currents of up to600-mA at voltages from 4.5 V to 36 V. Both devices are designed to drive inductive loads such as relays, solenoids, dc and bipolar stepping motors, as well as other high-current/high-voltage loads in positive-supply applications. All inputs are TTL compatible. Each output is a complete totem-pole drive circuit, with a Darlington transistor sink and a pseudo-Darlington source. Drivers are enabled in pairs, with drivers 1 and 2 enabled by 1,2EN and drivers 3 and 4 enabled by 3,4EN. When an enable input is high, the associated drivers are enabled, their outputs are active and in phase with their inputs. When the enable input is low, those drivers are disabled and their outputs are off and in the high-impedance state. With the proper data inputs, each pair of drivers forms full-H (or bridge) reversible drive suitable for solenoid or motor applications. [3]
· Wide Supply-Voltage Range: 4.5 V to 36 V
· Separate Input-Logic Supply
· Internal ESD Protection
· Thermal Shutdown
· High-Noise-Immunity Inputs
· Functional Replacements for SGS L293 and SGS L293D
· Output Current 1 A per Channel (600mA for L293D)
· Peak Output Current 2 A per Channel (1.2 A for L293D)
· Output Clamp Diodes for Inductive Transient Suppression (L293D)
FIGURE 4.3.5: PIN CONFIGURATION OF L293
4.3.6 WIRELESS CAMERA
Camera is the audio/video capturing equipment that essentially helps to monitor the changes taking place in the environment. Camera can have different resolutions. The specifications of wireless camera we used are:
· Model: AX-322 2.4G
· Resolution 380TVLine Outdoor
· 30 LED night vision system
· Long operation range: up to 100m line of sight or 30m through obstructions (walls/ceilings)
· High quality Colors CMOS sensor for crisp, clear images
· Weatherproof with sturdy alloyed shell for outdoor use
· Built-in microphone for audio monitoring
· Transmission Power: 10mW consumption current: 80mA and 120mA(LED ON)
· Power DC 9V-12V
FIGURE 4.3.6: WIRELESS CAMERA
4.3.7 LM 7809 VOLTAGE REGULATOR
The 78xx is a family of self-contained fixed linear voltage regulator circuits. The 78xx family is commonly used in electronic circuits requiring a regulated power supply due to their ease-of-use and low cost. For ICs within the family, the xx is replaced with two digits, indicating the output voltage (for example, the 7805 has a 5 volt output, while the 7809 produces 9 volts).In our project we have used LM7809 for regulated 9V dc to wireless camera.[2]
lm7809.jpg
Text Box: FIGURE 4.3.7: LM 7809
4.3.8 POTENTIOMETER
Potentiometer is the variable resistor. Potentiometer is resistor where the resistance can be changed using a knob or a slider. Potentiometer is used to control many things. The idea of this device this could be used to control the amount of electricity going to a component.
Here in our project we use potentiometer for joystick. Joystick is the device to control the Robot in desired fashion. The analog value obtained by rotating the potentiometer is converted into digital values via the Arduino board. Angle values for each servo motor is transmitted by required calculation of values from each potentiometer to rotate servomotor from 00 to 1800.We have used six potentiometers corresponding for each node of arm (servomotor) movement. [3]
pots-f5.jpg
FIGURE 4.3.8: POTENTIOMETER
4.4 WIRELESS TECHNOLOGY
In communication system, wireless communication is used to transfer over short distance or long distances. It encompasses various types of fixed, mobile, and portable systems and wireless networking. Wireless technology permits services, such as long range communications, that are impossible or impractical to implement with the use of wires. It has adverse use in telecommunication systems.
Wireless communication can be via:
· Radio frequency communication
· Microwave communication, for long- range line- of- sight or short- range.
· Infrared short-range communication
For wireless communication in our project we have used Bee (RF module pair). XBee is of IEEE 802.15.4 standard used for wireless transmission within the range of ISM 2.4GHz frequency band. [1] For interfacing with receiver and transmitter module we have used here XBee RF modules and it was interfaced with the user section robot section using XCTU software. [8]
4.5 RADIO FREQUENCY
Radio frequency is a rate of oscillation in the range of about 3 KHz to 300 GHz which corresponds to the frequency of radio waves and the alternating current which carries radio signals. RF usually refers to electrical rather than mechanical oscillations; however, mechanical RF systems do exist. RF includes the frequencies used for communications signals (as for radio and television broadcasting and cell-phone and satellite transmissions) or radar signals. [1]
if u like the post just say thank u in comment box.
4. PROJECT DETAILS
4.1 DESIGN BACKGROUND
Our project is divided into two parts viz.
· User section
· Robot section
4.1.1 USER SECTION
This section is facilitated by the use of Joystick and buttons to control the robot. The position of Joystick determines the position of arm. On the movement of joystick, TX microcontroller sends the angular position of Joystick to the robot so that robot-side microcontroller could receive the angular position and command the servomotors to have desired position.
Major components of this section are:
· Potentiometer
· Keypad
· RF transmitter (XBee)
· Arduino board
· Monitor display
4.1.1.1 DESIGN OF JOYSTICK
Joystick to our project is an electromechanical device we designed using POT (Potentiometer) and fiber glass to control our Robotic arm. It consists of fiber glass plates assembled using grip and screw along with glue. Main component of this module is potentiometer.
FIGURE 4.1.1.1: JOYSTICK DESIGN
4.1.1.2 OPERATION
This joystick acts as a remote controller to the Robotic arm. Potentiometer is used to calculate the angular positions of joints of joystick. Joystick comprises a microcontroller module to analyze the angular data to control the robot section. Analog value from POT is fed to microcontroller module via analog pins and converted to 10bits long digital integer, which is then converted to angle in degree.
This angular value is transmitted to robot section using ISM band 2.4 GHz microwave using XBee RF module.
In our project angular value is transferred to robot section using ASCII codes (viz. 65>> A). Our project has two modes (viz. manual and Auto mode). Mode selection is done using push button in joystick. This mode change information is also sent to robot section via XBee RF module as ASCII char. Since both control signals and data are sent via same channel so, to prevent the ambiguity we figured out the solution. Solution is to create our own frame format to indicate that data has arrived not control signal.
Packet format:
@#<angle1><angle2><angle3><angle4><angle5><angle6>
Example of Packet Format: @#a4%6g!
4.1.2 ROBOT SECTION
This section is the main section of our project. Every desired operation is performed in this section, by the reception of signals transmitted from the user section. The wireless camera attached to this section continuously transmits the captured pictures to display on the monitor in user side. The DC motor and the Servomotor perform the movement as instructed from the user section. The main function of the Gripper is to grab the object and lift it up.
The robotic arm simulates the human arm in similar fashion as possible. Smoothness of the movement is dependent on how good is the user in using the joystick.
Major components of the part are:
· Arduino board
· PCB with complete circuitry
· Wireless camera
· RF receiver (XBee)
· Servomotors
· DC motors
· Caster wheel
· Wheels
· Led
· Motor driver IC (L293)
· Chassis (Plywood) and aluminum sheet
4.1.2.1 MECHANICAL DESIGNS
Mechanical part designs have been the toughest task while doing our project. Being from the electronics background we don’t have much knowledge about mechanical parts. We go through different websites, consulted people from mechanical background and we designed our mechanical parts as fallow as we feel appropriate according to the methods and components available to us. [5]
FIGURE 4.1.2.1 (a): DESIGN OF LOWER PART OF ARM
FIGURE 4.1.2.1 (b): DESIGN OF UPPER PART OF ARM
FIGURE 4.1.2.1 (c): DESIGN OF GRIPPER
4.2 METHODOLOGY
4.2.1 PROBLEM ANALYSIS
From ancient time human have been employed in areas where risk is maximum. Traditional method of solving problems were/are time consuming and error prone. So to achieve the maximum efficiency and reduce the risk in mankind we thought to build a movable robotic arm capable of doing human jobs. This solves the problem and also saves time and human effort.
4.2.2 RESEARCH AND TESTING
The technology used in our project is completely new to us so we obviously have got updated about new era of robotics and electronics. Different websites, worldwide and previous research papers was helpful to accomplish our project.
FIGURE 4.2.2 (a): TESTING IN ARDUINO MONITOR
FIGURE 4.2.2 (b): TESTING OF TRANSMISSION AND RECEPTION IN X-CTU
4.2.3 PROJECT SKETCHING AND MECHANICAL DESIGN
Since our project is electro-mechanical in nature, it needs proper sketching and designing in well-defined manner. Sketching gives the idea for cutting the frames out of the fiber glass-sheets. The chassis of the arm and body was made from fiber glass sheets. The arm consists of multiple joints on the basis of which the arm will operate.
4.2.4 SOFTWARE DEVELOPMENT AND SIMULATION
We have built our own control panel software for Windows and we will be operating the robot partially from computer and partially from joystick that we designed especially for our project. Firmware for the microcontroller was written in c and compiled in Arduino IDE. For simulation we used ISIS (Proteus).
FIGURE 4.2.4(a): SIMULATION OF ROBOT SIDE
FIGURE 4.2.4(b): SIMULATION OF USER SIDE (JOYSTICK)
4.2.5 CIRCUIT DESIGNING AND IMPLEMENTATION
The overall project needs electrical power and necessary circuit to function. So our next step was circuit designing. After successful simulation we have move forward towards circuit designing using software such as Eagle, PCB Wizard, ARIES, etc. to design PCB. The design is printed, pressed and etched. Circuit board was then drilled and components were soldered.
4.2.6 ASSEMBLY OF MODULES
Modules such as Robotic Arm, Robotic Base, Circuit Board, wireless transmitter, receiver, wireless camera, and Wires were assembled in well-functioning fashion.
4.3 COMPONENTS DESCRIPTION
For the completion of our project we have used the following components. Their description in details is as follows.
4.3.1 SERVO MOTOR
Servo refers to an error sensing feedback control which is used to correct the performance of a system. Servo or RC Servo Motors are DC motors equipped with a servo mechanism for precise control of angular position. The RC servo motors usually have a rotation limit from 90° to 180°. But servos do not rotate continually. Their rotation is restricted in between the fixed angles. The Servos are used for precision positioning. They are used in robotic arms and legs, sensor scanners and in RC toys like RC helicopter, airplanes and cars. [3]
Here in our system we have used seven servo motors for arm motion. In every corner of arm is handled by servomotor. Every movement of arm is handled by servomotor which is controlled by PWM from Arduino. Mechanical movement provides desired output for the system.
FIGURE 4.3.1: SERVO MOTOR
4.3.2 DC MOTOR
DC geared motor is an electric motor that uses electricity and a magnetic field to produce torque, which turns the motor. DC motors are intended to drive the robot body and the camera direction. Here DC motor is controlled by control panel. DC motors are arranged in such a way that both the robot body and camera can move in all four directions. Most DC motors are normally very easy to reverse; simply changing the polarity of DC input will reverse the direction of the drive shaft. This change over process can be achieved via a simple changeover switch or for remote or electronic control, via a suitable relay. Another big advantage of DC motors is that variable speed control is easy and can achieve with just a suitable variable resistor or variable power supply. For more precise control and maximum efficiency there is much other electronic PWM (Pulse Width Modulation) solution although these tend to have added complexity. Most DC motors are designed to exhibit the same speed and output torque in either the forward or reverse direction. Drive shaft speeds rpm (round per minute) are quoted with motor unloaded. [3]
FIGURE 4.3.2: DC MOTOR
4.3.3 ARDUINO BOARD
Arduino is an open source physical computing platform based on a simple input/output (I/O) board and a development environment that implements the Processing language. Arduino can be used to develop standalone interactive objects or can be connected to software on your computer (such as Flash, Processing, or Max/MSP). The boards can be assembled by hand or purchased preassembled; the open source IDE (Integrated Development Environment). [6]
arduino.jpg
FIGURE 4.3.3: ARDUINO BOARD
Some features of Arduino are:
Ø It is a multiplatform environment; it can run on Windows, Macintosh, and Linux.
Ø It is based on the Processing programming IDE, an easy-to-use development environment used by artists and designers.
Ø We program it via a USB cable, not a serial port. This feature is useful, because many modern computers don’t have serial ports.
Ø It is open source hardware and software.
Ø The Arduino Project was developed in an educational environment and is therefore great for newcomers to get things working quickly.
The Arduino board is a small microcontroller board, which is a small circuit (the board) that contains a whole computer on a small chip (the micro-controller).The Atmel atmega328 microcontroller is the heart of the Arduino board. [4]
Arduino board consists of 14 Digital IO pins (pins 0-13), 6 Analog In pins (pins 0-5), 6 Analog Out pins (pins 3, 5, 6,9,10 and 11).
4.3.4 XBEE PAIR (RF MODULE)
XBee is IEEE 802.15.4 standard RF module for wireless transmission and receiver. It is low cost, low power wireless sensor network operate within the ISM 2, 4 GHz frequency band. It can operate up to 90-100 meters to Trans-receive the signal. Data rate of this module for serial interface is 1200bps- 250kbps. Transmit power is 1mw (0dBm) and receiver sensitivity is -92dBm. The transmit peak current at 3.3V is 45mA and receiver current at 3.3V is 50mA.
Some features of XBee are:
§ Facilitated with 20pins
§ UART serial data transmission
§ Low power consumption
§ Easy to use with the help of X-CTU software
§ Serial interface Data rate: 1200bps- 250kbps
§ Operate in ISM 2.4GHz frequency band
§ Data integrity: Indoor (up to 30m) and outdoor (u)
It can function in two different operation mode viz. transparent mode and API (Application Programming Interface) mode. [7]
FIGURE 4.3.4: XBEE MODULE
4.3.5 MOTOR DRIVER IC L293
The L293 and L293D are quadruple high-current half-H drivers. The L293 is designed to provide bidirectional drive currents of up to 1 A at voltages from 4.5 V to 36 V. The L293D is designed to provide bidirectional drive currents of up to600-mA at voltages from 4.5 V to 36 V. Both devices are designed to drive inductive loads such as relays, solenoids, dc and bipolar stepping motors, as well as other high-current/high-voltage loads in positive-supply applications. All inputs are TTL compatible. Each output is a complete totem-pole drive circuit, with a Darlington transistor sink and a pseudo-Darlington source. Drivers are enabled in pairs, with drivers 1 and 2 enabled by 1,2EN and drivers 3 and 4 enabled by 3,4EN. When an enable input is high, the associated drivers are enabled, their outputs are active and in phase with their inputs. When the enable input is low, those drivers are disabled and their outputs are off and in the high-impedance state. With the proper data inputs, each pair of drivers forms full-H (or bridge) reversible drive suitable for solenoid or motor applications. [3]
· Wide Supply-Voltage Range: 4.5 V to 36 V
· Separate Input-Logic Supply
· Internal ESD Protection
· Thermal Shutdown
· High-Noise-Immunity Inputs
· Functional Replacements for SGS L293 and SGS L293D
· Output Current 1 A per Channel (600mA for L293D)
· Peak Output Current 2 A per Channel (1.2 A for L293D)
· Output Clamp Diodes for Inductive Transient Suppression (L293D)
FIGURE 4.3.5: PIN CONFIGURATION OF L293
4.3.6 WIRELESS CAMERA
Camera is the audio/video capturing equipment that essentially helps to monitor the changes taking place in the environment. Camera can have different resolutions. The specifications of wireless camera we used are:
· Model: AX-322 2.4G
· Resolution 380TVLine Outdoor
· 30 LED night vision system
· Long operation range: up to 100m line of sight or 30m through obstructions (walls/ceilings)
· High quality Colors CMOS sensor for crisp, clear images
· Weatherproof with sturdy alloyed shell for outdoor use
· Built-in microphone for audio monitoring
· Transmission Power: 10mW consumption current: 80mA and 120mA(LED ON)
· Power DC 9V-12V
FIGURE 4.3.6: WIRELESS CAMERA
4.3.7 LM 7809 VOLTAGE REGULATOR
The 78xx is a family of self-contained fixed linear voltage regulator circuits. The 78xx family is commonly used in electronic circuits requiring a regulated power supply due to their ease-of-use and low cost. For ICs within the family, the xx is replaced with two digits, indicating the output voltage (for example, the 7805 has a 5 volt output, while the 7809 produces 9 volts).In our project we have used LM7809 for regulated 9V dc to wireless camera.[2]
lm7809.jpg
Text Box: FIGURE 4.3.7: LM 7809
4.3.8 POTENTIOMETER
Potentiometer is the variable resistor. Potentiometer is resistor where the resistance can be changed using a knob or a slider. Potentiometer is used to control many things. The idea of this device this could be used to control the amount of electricity going to a component.
Here in our project we use potentiometer for joystick. Joystick is the device to control the Robot in desired fashion. The analog value obtained by rotating the potentiometer is converted into digital values via the Arduino board. Angle values for each servo motor is transmitted by required calculation of values from each potentiometer to rotate servomotor from 00 to 1800.We have used six potentiometers corresponding for each node of arm (servomotor) movement. [3]
pots-f5.jpg
FIGURE 4.3.8: POTENTIOMETER
4.4 WIRELESS TECHNOLOGY
In communication system, wireless communication is used to transfer over short distance or long distances. It encompasses various types of fixed, mobile, and portable systems and wireless networking. Wireless technology permits services, such as long range communications, that are impossible or impractical to implement with the use of wires. It has adverse use in telecommunication systems.
Wireless communication can be via:
· Radio frequency communication
· Microwave communication, for long- range line- of- sight or short- range.
· Infrared short-range communication
For wireless communication in our project we have used Bee (RF module pair). XBee is of IEEE 802.15.4 standard used for wireless transmission within the range of ISM 2.4GHz frequency band. [1] For interfacing with receiver and transmitter module we have used here XBee RF modules and it was interfaced with the user section robot section using XCTU software. [8]
4.5 RADIO FREQUENCY
Radio frequency is a rate of oscillation in the range of about 3 KHz to 300 GHz which corresponds to the frequency of radio waves and the alternating current which carries radio signals. RF usually refers to electrical rather than mechanical oscillations; however, mechanical RF systems do exist. RF includes the frequencies used for communications signals (as for radio and television broadcasting and cell-phone and satellite transmissions) or radar signals. [1]
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its cool