Tuesday, 23 April 2013


The AMWR was designed for application in inaccessible places, or in inhospitable situations for humans. A full scale version of AMWR could be used for many real world applications such as military reconnaissance, extreme condition (environment) vehicles, or in artificial intelligence robotics. Another application could be in schools, colleges, and universities interested in experimentation and development of robots. AMWR, the remotely controlled robot, has several key components.

 This robot consists of a PIC 16F877A microcontroller interfaced with the motor controls of a DC gear motor. This microcontroller is responsible for decoding the correct control signals when given a control byte, and sending these control signals to the motor controls. In addition, to these two sensors are also connected to the microcontroller. These sensors are placed to measure temperature and humidity. Remote communication to the AMWR is accomplished using zigbee. The remote control module using zigbee is connected to a pc using a serial cable (RS-232) at baud rate 9600.In order to provide feedback from the robot; an android mobile phone camera is attached to the robot. A 2.4 GHz wireless link provided, along with the camera used to communicate with the controlling PC. PLC software running on the controlling computer is responsible for converting instruction given by a user into a byte code, and sending it to the zigbee module via db9 serial port of the PC.

The major objectives of the robot are embedded control of a robot, atmospheric condition measurements, zigbee based communication, live video feedback, and PC-based direction. Zigbee can penetrate walls and be used in places where a wired network is either not suitable or cannot be established. The advances in the wireless technology have made it possible to establish a network just by placing the communicating nodes at the required places and switching on the transmitters in them. It is possible to have great transfer rates even at long ranges. With such usefulness and many more features, a wireless network is the surely needed in places where it is not possible to establish a network using wires. Also, in case of cave-ins, or an explosion the wire may get damaged making the entire network useless.

Zigbee is used to overcome all the shortcomings of a wired network. With its great range even through solid objects such as walls or in this case it is the most suited technology for our purpose. Another improvement that can be implemented in the future is autonomous obstacle avoidance. Once an obstacle has been detected and the robot stopped, it is up to the user to decide how to go around the obstacle using the video feedback. However, in the future, proximity sensors can be used to actively avoid obstacles and go around them instead of stopping to let the user decide the next movement. Robot section The AMWR contains the motion control motors, sensors for atmospheric condition measurement, zigbee module for communication with control section and a mobile camera. All of the components in the robot are controlled by a microcontroller (PIC16F877A).The robot circuit as shown above consist of the integral part or heart of the robot – PIC16F877A to which rest all the peripherals are connected. The peripherals can be classified as two they are: . Motion control and atmospheric measurement. . Communication. The circuit works as follows, on receiving control signals via zigbee module from the control section. The PIC micro controller according to the programme in it executes the necessary operations. The operations mainly include robot motion control. It is done by controlling two motors of 45rpm to run in clockwise or anticlockwise direction according to the required movement. Next comes the sensor data sending to control station from the robot. This is done with help of ADC module, USART module in the PIC microcontroller and via zigbee module (for communication) to control station. Two sensors used are LM35 and HM1500. That is Temperature and humidity sensors respectively. The output from temperature sensor is analog it given to the mc in the pin2 as output of humidity is as analog it given to the pin3, The mc convert these analog output t digital and given to the zigbee. Zigbee transmit this data to control section. The motor control from the control section received the zigbee and the data given to the mc. MC after processing the signals and given to the motor driver ic L239d. As per the output from the mc the L239d drive the gear motors in clockwise or anticlockwise direction. Here a crystal oscillator used to giving proper frequency for the mc. As the capacitors .01μF for the stability of the mc. We can as use this car as wired one by connecting it into usart via max232. It is used to converting TTL/CMOS to RS232 and CMOS/TTL to RS232 logic. Control Section

 The AMWR is controlled by a remote control module using zigbee for communication. The module is connected to a PC through its DB9 serial port. The remote control module consists of a max 232 IC and an XBee/XBee-PRO RF Module with help of a GUI developed on java platform.The data from usart given to the max232 and it convert CMOS/TTL into RS232 logic and given to the zigbee and it transmit to robot section. RS232 is -30 to +30V and the TTL is -5 to +5V. The motor direction given by using pc software. Also data from the robot section are seen on the display . The data are temperature and humidity values. The motors can be used to make the car and sensors as well as camera can be place.

 Components Required 

 PIC 16F877A - 1
MAX232 - 2
LM35 - 1
HM1500 - 1
L293D - 1

 22pF - 2
 1μF - 8
 100μF - 1
Crystal oscillator 11.0592MHz - 1
Diode 1N4001 - 4
Resistor 10K - 3
Push button - 1

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