Professor Dhananjay Gadre is a certified AVR Consultant and has written a book on the subject together with numerous other articles in various magazines. It was one of these articles that prompted me to contact him via email. From then on I have in constant touch with him. I had let him know about Robocon and how our college had been faring in it over the years. Since he was in Pune at the time of the competition this year, I invited him to look at our robots during our stay at MIT, Pune.
He met our guide Professor Abhay Kshirsagar and it was then that the idea for conducting the AVR Microcontroller Workshop came around. On returning from Pune we immediately set towards organizing the workshop. Professor Gadre has quite a lot of experience in holding such workshops so organizing it was a breeze. We were constantly in touch with him via email and phone. He had developed 2 kits for such workshops and had agreed to bring those for the participants to work on.
The following are the details of the workshop:
Day 1 : 1300-1900 Hrs, Thursday, 01 September, 2005
On the first day Professor Gadre taught us the basic principle of designing an embedded system. He threw light on the various constraints which a design engineer must take into account before designing a system. He started right from enumerating the differences between a microcontroller and a microprocessor and went on to speak about topics like Real Time Processing and Hardware/Software Partitioning which lie at the core of the subject. He made the atmosphere lively by sharing anecdotes and practices followed by the industry in this field.
After the Tea break, the kits (PCB and components) were distributed. The participants were divided into groups of 3 each and each was assigned the task of soldering a kit. The idea behind getting the students to solder the kits themselves was to let them get the feel of the microcontroller system before they went on to program one. The whole exercise took on a totally different track when all of us soldered the wrong resistors on the PCB. From then on it was what one would call an “Organized Chaos”. Students had to get on to de-solder the wrongly placed components and put in new ones in their place. Such an incident helped the students become more aware of the problems which one might face when creating an embedded circuit and how they could prevent those by carefully paying attention to each step involved in the process.
In all, the first day turned out to be a fun exercise.
Day 2 : 1300-1900 Hrs, Friday, 02 September, 2005
In the morning, before the workshop, some of us took on the tasks of rectifying the errors which the students had made while soldering the kits the day before and we were able to fix all of those kits before the workshop began.
Professor Gadre spoke about the features of AVR Microcontrollers. He also spoke about the instruction set in brief and at the end he assigned us the task of controlling the brightness of LEDs using the technique of PWM by writing a simple program in assembly language. Some of us completed this exercise on the same day while the rest of us were successful in doing it by the start of the next day.
Day 3 : 1300-1900 Hrs, Saturday, 03 September, 2005
In the morning we took Professor Gadre to Lamington Road where he bought some components for future workshops. On returning back for the workshop, he explained more about the AVR Microcontroller series and the onboard resources available on these microcontrollers.
He explained about implementing serial communications by giving us an example of how one could design a system similar to the voting system used in the television programme “Kaun Banega Crorepati”. The idea was to use the RS-485 Communications protocol to carry out broadcast and unicast commands on the same network.
After the tea break we made a list of projects that we would make for presenting on the Technology Day. Each group was assigned a project and we set to work on them.
Day 4 : 0900-1900 Hrs, Sunday, 04 September, 2005
We spent the whole Sunday completing the projects which we had taken up. At the end of the day, all of us were successful in finishing the project with much time to spare.
At the end of day 4 we had a photo session before the official end of the AVR workshop. We thanked Professor Gadre for spending his valuable time to teach us the basics of the AVR Microcontroller.
Technology Day: Monday, 05 September, 2005
On the Technology Day we presented our projects to the college staff and students.
The projects which we had made during the workshop were:
Brightness control of LEDs using Pulse Width Modulation - The brightness of LEDs were varied by changing the on and off times (Duty Cycle) of the square wave applied to them.
Real Time Clock - A Real Time Clock was designed using the onboard counter and timers and the computer terminal was used as a display. The microcontroller communicated with the computer using the onboard USART.
Inter-Microcontroller Communication using PORT pins - A running LED pattern was implemented using total of 8 LEDs; 4 each from two different microcontroller boards. The microcontroller communicated with each other to display a continuous pattern spanning all 8 LEDs
Digital Oscilloscope - The onboard Analog to Digital of the AVR Microcontroller was used to sample the input voltage and the waveform was displayed on the computer terminal using USART
Displaying Patterns on a CRO - A Microcontroller with 2 attached DAC was used to control the electron beam in X-Y Mode to display any pattern of our choice.
Electronic Dice - An Electronic Dice was made by using seven LEDs and the on board counters. The random nature of the time elapsed between two key presses by the user served as the randomizer for the Dice.
Multi Counter - A counter which was able to count in binary patter or Gray code pattern or Excess-3 Pattern was made. The counting mode was selected by input from computer terminal via USART
White Line Detecting Circuit – A circuit was made to detect a white line from a dark colored background.
We received an overwhelming response from the staff and students. The first year students were particularly enthusiastic in getting a first hand look at such projects. We told them how they could go about making such circuits. We promised to provide them help in the future for organizing such workshops and any projects that they may want to take up.
In all, the AVR workshop has been a pleasant experience and we have learned a lot from it. Thanks to Professor Gadre’s insight and experience, we were able to achieve more than we could imagine. Due to lack of space, we could only allow the fourth year students and the VESIT Robocon 2005 Team for this workshop. We hope to hold such workshop again in the future for the second and the third year students also.