Project 1: Analog to Digital Conversion and Digital Input/Output

All components of the project are due by Thursday, February 25th at 5:00pm. Please start early (this is not a single-session project).
Groups are composed of 3-4 students.
Discussion within groups is fine.
Discussion across groups may not be about the specifics of the solution (general programming/circuit issues are fine to discuss).

Project Goals

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

create simple microcontroller-based circuits,
read analog information through the Atmel Analog-to-Digital converter,
read digital information from a switch, and
convey information about sensors using a set of LEDs

Circuit Overview

By the end of the semester, you will have a circuit on a single breadboard that includes the following components:

one atmel microcontroller with supporting hardware (including crystal and programming interface),
one motor driver board for control of the fans,
one analog gyroscope sensor,
two switches,
four LEDs arranged in a circle (for indicating heading and heading error), and
five LEDs arranged in a line (for indicating rotation rate or sensed distances).

Not on the breadboard, but connected to it will be:

three ducted fans,
a compass module,
two analog distance sensors, and
a power system.

Project 1 Requirements

For project 1, your circuit with associated software must be able to:

read rate gyro and distance information from the corresponding sensors,
read the state of a connected switch, and
display the sensor states depending on the state of the switch.

As you are laying out the circuit on your breadboard, keep in mind the space requirements of the components that you will be installing later in the semester. If you have questions about these constraints, see Di's example circuit. (Note: if you need temporary use of an extra breadboard, please ask).

Project Components

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

Part 1: Microcontroller Circuit

Create a mega8-based circuit on a solderless breadboard.

See the bottom of the Atmel HOWTO for a circuit starting point. This contains everything that you need to create a programmable mega8.
Add the gyro module to the board. Provide this module with power (+5V) and ground inputs. The analog output should be connected to pin 23 (ADC0).
Connect to the board the two analog distance sensors. Each require power (+5V) and ground inputs. The analog outputs should be connected to pins 24 (ADC1) and 25 (ADC2).
Add a set of 4 LEDs that will be used to display the current heading of the craft (organized in a circle). Each of these LEDs should be driven by a digital output pin.
Add another set of 5 LEDs that will be used to display the heading velocity (organized in a line). Each of these LEDs should be driven by a digital output pin.
Add a switch. One end of the switch will be connected to ground, the other to a digital input pin. This pin should also be "pulled up" to +5V using a 10 K-Ohm resistor. The toggle switch will connect the pin directly to ground when first pressed, which will result in a logic "0" on the pin. Pressing the switch again will disconnect the connection to ground and will result in a logic "1".

Part 2: Rate Gyro

Note: this part will count for one personal programming credit

Create a main program that:

Properly initializes the I/O ports.
In a while(1) loop, continuously reads the sensors and displays one of their values using the set of 5 LEDs.
If the switch is in a logic 0 state, then the gyro state should be displayed.
If the switch is in a logic 1 state, then one of the distance sensor states should be displayed.

Implement the following functions to support your main() function (these are requirements):

int16_t get_rotation_rate(void) will read the analog port attached to the gyro sensor and return the value in 10ths of a degree per second. Note that a return value of zero should correspond to no rotation, positive values should correspond to counter clock-wise rotations, and negative values should correspond to clock-wise rotations.
void display_rotation_rate(int16_t rate) will change the state of the 5 LEDs (and no others) to reflect the current rotation rate.

Part 3: Distance Sensor

Note: this part will count for one personal programming credit

Implement the following functions:

uint16_t get_left_sensor(void) will read the analog port attached to the left distance sensor and return the value in mm. Note that a low magnitude return value should correspond to a short distance.
uint16_t get_right_sensor(void) will read the analog port attached to the right distance sensor and return the value in mm.
void display_left_sensor(uint16_t dist) and void display_right_sensor(uint16_t dist) will change the state of the 5 LEDs (and no others) to reflect the current distance.

Part 4: Lift Fan

Cut a hole in the frisbee and mount the lift fan over the hole.

References

Atmel HOWTO
Hardware in the Lab (including the USB-TO-RS232 converters -- see the FTDI ft232r section)

What to Hand In

All components of the project are due by Thursday, February 25th at 5:00pm.

Demonstration/Presentation: All group members must be present.
- Demonstrate your final product.
- Present your design and implementation (5 minutes). The group is responsible for assembling a short presentation consisting of 3-4 slides (on computer or in printed form). Describe the design including:
  - which team members were responsible for what components (including the personal programming components),
  - the circuit,
  - your software solution for transforming the analog value read from the gyro into the returned integer,
  - your software solution for displaying sensor values,
  - DO NOT include low-level code (only give the general logic)
Code: Turn in your documented code to the group project 1 digital dropbox on D2L (hand in the ".c" file). Only hand in one copy of the code per group.
Remember that documentation is about helping you and others looking at your code to understand what it is doing. Therefore, it will generally describe the logic of the code (and not-necessarily the low-level details). For this class:
1. Each function must be documented (at the top of the function) as to what it does logically, what the meaning is of its inputs, and what the returned value is. If the function has external effects (e.g., commanding an actuator or modifying a global variable, these should also be documented here)
2. In-line comments should be used to describe logically what is happening at that line or group of lines.
See an example.
Personal report: One submission per person to the personal project 1 digital dropbox in text format only (e.g., M$word has a save-as text option in the File menu. In this report, briefly state:
1. Who performed which personal programming component. Assess the degree to which they performed this task. The ideal scenario is that they performed a large majority (80% or more) of the task.
2. Of the remaining project pieces, state the relative contributions of you and your group members in terms of percentage of effort. The ideal distribution is equal across all group members. In extreme cases in which effort is not equitable, this distribution will be used to weight individual grades.

Grading

Group grade distribution:

40%: Project implementation
30%: Demonstration/presentation of working project (to either of the TA or the instructor)
30%: Code documentation and group report

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

fagg [[at]] cs.ou.edu

Last modified: Thu Feb 25 00:51:49 2010