14-05-2011, 12:01 PM
Introduction
The goal of our project was to build a robot which followed an active source of light. Our vehicle
uses optical sensors(photodiodes) to follow a moving light source which in our case is a torch held
by the user. The hardware is self constructed and thus was the major part of our work.
High-Level Design
Our vehicle uses photodiodes to locate its postition relative to the light source. The state of the
photodiodes is captured, and the car is controlled accordingly by an Atmel ATMEGA16
microcontroller. If the car detects a small perturbation(change in intensity of the oncoming signal),
it will correct its path by steering in the appropriate direction.
The original objective for this project was to optimize the car for the speed with which it navigated
the path. To do this, we would have increased the speed when little compensation was needed, and
decreased the speed as more was needed. This optimization, however, did not require much more
effort on our part than the heuristic outlined above. This is because the speed is mechanically
regulated by the gradual acceleration(increae/decrease) of the car in balance with the direction
reversal for large corrections.
Hardware
The hardware for this project was the bulk of the work. Because we were making a moving vehicle,
we decided that it would be best not to have any of the circuitry on breadboards. Breadboards are
also expensive, so we probably would have had to disassemble the car after its demonstration. We
therefore chose to wire-wrap all of the circuitry. This required a fair amount of labor, but it was well
worth it in the end.
The car we selected is fairly simple to operate. It has a simple two wheel drive, , which is powered
by a DC motor. The steering is achieved by applying a difference of voltages acroos the two
batteries. We used two H-bridges (L293D) to deliver power to the steering and the drive motor.
Because of the current requirements (the drive motor and steering solenoid could draw several
amps), we used 20-gauge wire for the high-current areas of the H-bridges rather than the 30-gauge
wire used for the rest of the circuit.
Download full report
http://me.iitb.ac~kaushikj/lightfollower.pdf
The goal of our project was to build a robot which followed an active source of light. Our vehicle
uses optical sensors(photodiodes) to follow a moving light source which in our case is a torch held
by the user. The hardware is self constructed and thus was the major part of our work.
High-Level Design
Our vehicle uses photodiodes to locate its postition relative to the light source. The state of the
photodiodes is captured, and the car is controlled accordingly by an Atmel ATMEGA16
microcontroller. If the car detects a small perturbation(change in intensity of the oncoming signal),
it will correct its path by steering in the appropriate direction.
The original objective for this project was to optimize the car for the speed with which it navigated
the path. To do this, we would have increased the speed when little compensation was needed, and
decreased the speed as more was needed. This optimization, however, did not require much more
effort on our part than the heuristic outlined above. This is because the speed is mechanically
regulated by the gradual acceleration(increae/decrease) of the car in balance with the direction
reversal for large corrections.
Hardware
The hardware for this project was the bulk of the work. Because we were making a moving vehicle,
we decided that it would be best not to have any of the circuitry on breadboards. Breadboards are
also expensive, so we probably would have had to disassemble the car after its demonstration. We
therefore chose to wire-wrap all of the circuitry. This required a fair amount of labor, but it was well
worth it in the end.
The car we selected is fairly simple to operate. It has a simple two wheel drive, , which is powered
by a DC motor. The steering is achieved by applying a difference of voltages acroos the two
batteries. We used two H-bridges (L293D) to deliver power to the steering and the drive motor.
Because of the current requirements (the drive motor and steering solenoid could draw several
amps), we used 20-gauge wire for the high-current areas of the H-bridges rather than the 30-gauge
wire used for the rest of the circuit.
Download full report
http://me.iitb.ac~kaushikj/lightfollower.pdf
