Project 3: Sensor Control and Distance Sensing

All components of the project are due by Wednesday, April 18th at 5:00pm.

Project Goals

At the end of this project, you should be able to:

Hardware Overview

Each test station is equipped with a Devantech sonar sensor unit. Each unit is equipped with a sonic transmitter which will emit a small burst of clicks. The receiver will sense the signal that has reflected off of some surface. By measuring the return time of the signal, we can infer the distance to the surface.

For the heli stations, the sensors will be placed underneath the helicopter (facing upwards). This way, we can measure the height of the heli at a given time. In project 4, we will use this information to hover the heli at some specified height.

The interface to the sonar unit is as follows:

Note: After the reflected signal has been detected, you must wait for at least 10 msec to command the next sonic pulse.

Hint: consider using a counter that tells the ISR "what time it is" (e.g., when to emit the burst, when it is measuring the pulse, and when it is waiting before it emits the next pulse).

Project Overview

For this project, you will modify your microcontroller circuit to provide an interface to the sonar unit. In addition, you will be writing the software that is necessary to control the sonar and interpret the signals that you receive from it.

Note: in the next project, you will be integrating the current work into the helicopter control problem (and doing height and yaw control simultaneously). So: do not completely dismantle your project 2 implementation.

In brief, your code must:

Project Components

All components are required to receive full credit for the project.

Part 1: Microcontroller Circuit

Designate one additional input pin and one output pin. Wire these into the sonar connector.

Part 2: Sensing Distance

Implement an interrupt service routine (e.g., one that is attached to the timer0 overflow interrupt) that does the following:

Part 3: Height Display


What to Hand In

All components of the project are due by Wednesday, April 18th at 5:00pm.


Group grade distribution:

Grades for individuals will be based on the group grade, but weighted by the assessed contributions of the group members.

fagg [[at]]

Last modified: Wed Apr 4 22:08:42 2007