• Motor Driver:

    We usually use DC geared motors for our Robots and hence we choose the driver depending on the current rating of the motor.

    • L-293: It is a very easy to use H-bridge Integrated Circuit, and can supply continuous current upto 1 A. So, we use this only for light motors.
    • L-298: It is just advance version of L-293, can supply continuous current upto 2 A and we can also increase it to 4 A by using two gates in parallel which we normally do.
    • Mosfets: For very high current rating motors which cant be driven by these ready made chips, we design H-Bridge using IRF-540 & IRF-9540 Mosfets. This circuit can supply huge current and we assume (as we have never reached max rating) it to reach 15A of continuous current as current rating of these mosfets is 20A.

 

  • Micro-controller:

    We have been working with AVR series of microcontrollers of Atmel for a long time, but recently we have started working on PIC series of microcontrollers from Microchip also.

    AVR (Atmel):

    • Use: We use Atmega - 8/16/32 as brain of our Robots. We have a habbit of assigning each microcontroller a specific task, like separate microcontroller for reading sensors which sends the data to main microcontroller which processes the data and sends the control information to motor driving microcontroller and hence we have separate boards for each task. Apart from common digital I/O functions the peripherals we commonly use are ADC (Analog input), Timers (CTC and PWM mode), SPI & USART (for communication), Interrupts (you must know why !) and LCD Interfacing.
    • Programmer: We have designed STK-500 compatible USB programmer based on Atmega-8 and it is very convenient for programming as it is supported by most of the programmers. In windows we use AVR-Studio and in Linux we use AVR-DUDE to burn the AVRs.
    • Compiler: Most of the time we use Code Vision AVR (CVAVR) because of its handy code wizard, but for advance and complicated programs we use AVRGCC and use our own libraries.

    PIC (Microchip):

    • Programmer: As we have just started work on PIC microcontrollers, we use JDM based Serial Programmer. Very soon we will be working out with USB based programmer. For burning we use PICPgm which works only on windows.
    • Compiler: For programming in Assembly we use MPLAB IDE. It also has option for using C18 compiler for writing codes in C. Mikro-C is also a very easy to use IDE for writing code in C.

 

  • LCD:

    Very often we have to use 2-3 microcontrollers and a number of sensors on a single Robot. So, to monitor and debug data transfers, sensor values we use LCDs to display the data. Simplest is 16x2 Hitachi LCD which is easily interfaced with AVR.

 

  • Sensors:

    Type of sensors depends very much on the problem statement. But for basic line following which is almost same every year we keep following 4 options with us, which also depends on the background color of the arena,

    • Design Analog IR based Sensors using IR Transistor.
    • Design Digital IR based Sensors using TSOP-1738.
    • Use readymade proximity sensors.
    • Use readymade visible light based analog sensors.
  • PCBs:

    Usually we design PCBs and get them fabricated from PCB Fabrication Lab of Electrical Engineering Department. The software we use for designing is Eagle which works both on Windows and Linux.

    However sometimes we end up soldering the circuit on a general purpose PCB !