AME 3623: Project 2:
Analog to Digital Conversion and Sensor Interfaces

• All components of the project are due by Tuesday, March 26th at 5:00pm.
• 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 Objectives

• read analog information through the Atmel Analog-to-Digital converter,
• using a sensor model, interpret analog voltages in terms of sensed quantities, and
• convey information about sensors using a set of LEDs and using serial output.

Project Components

Part 1: Microcontroller Circuit

• Connect a second switch to a digital input of your Mega2560

• Add the gyro module to the board. Provide this module with power (+5V) and ground inputs (note that 3 pins on the gyro need to be grounded). Connect the analog output to one of the analog inputs on the mega2560.

• Connect the two analog distance sensors to two analog inputs on the mega2560. Each require power (+5V; red), ground (black) and signal (other).

Part 2: Rate Gyro

Add to your main program:

• Properly initialize the I/O ports.
• In the while(1) loop, continuously read the new sensors, and display one of their values using the set of ten LEDs (the LED bar).

  Consider the two switches as representing two binary digits:

  • 00: display the gyro state
  • 01: display the left distance sensor
  • 10: display the right distance sensor

• Within the while loop, you must also write the current sensor values out to the serial port (see hints below).

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 clock-wise rotations, and negative values should correspond to counter clock-wise rotations (so, a left-handed coordinate system).

  The gyro will respond with a max of 3.3V, which corresponds to 300 degrees/sec, and a minimum of 0V, which corresponds to -300 degrees/sec (right handed coordinate frame). The gyro responds linearly to rotational velocities. Groups with blue bins: see Andy for small differences in this specification.

• void display_rotation_rate(int16_t rate) will change the state of the ten LEDs (and no others) to reflect the current rotation rate.

Part 3: Distance Sensors

Define a new variable type in "project.h":

typedef enum {
   LEFT = 0,
   RIGHT = 1
}DistanceSide;

DistanceSide is the variable type. LEFT and RIGHT are the two values that DistanceSide variables can take on. Remember to include "project.h" in your C file and add it to the Solution Explorer.

Implement the following functions:

• uint16_t get_distance(DistanceSide side) will read the analog port attached to the left distance sensor (if side == LEFT) or the right distance sensor (if side == RIGHT) and return the value in mm. The distance sensors are Sharp GP2Y0A21YK sensors

• void display_distance(uint16_t dist) and will change the state of the ten LEDs to reflect the current distance.

Part 4: Hovercraft Layout

• Batteries
• Forward thrust fans
• Breadboard
• Distance sensors. These should be mounted so that if the hovercraft is against a wall, there is at least 6cm between the sensor and the wall. You also need to mount them so that they do not "see" the hovercraft itself.

References

• Atmel HOWTO

• Hardware in the Lab (including our gyro)

• Downloads page (in particular, hyperterm will be useful for this project)

• Serial port 0 on the Mega2560 is connected to the USB connector that you plug into your laptop. You can use hyperterm to receive/send serial data from/to the Mega2560 (via fprintf, fputc, fputs and fgetc). You may use this serial interface to receive information from your program and to respond to commands from your laptop. To configure hyperterm, you will need to select the port (findable from the hardware section of your control panel) and serial bit (or baud) rate. In this case, it is 38400.

What to Hand In

• Demonstration/Presentation/Code Review: All group members must be present. You must reserve one hour with the instructor or TA for this process
  • 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 your 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 algorithm (the math) for transforming the analog value read from the sensors into the returned integer,
    • your algorithm for displaying sensor values,
    • DO NOT include low-level code (only give the general logic)

  Notes:

  • All team members must be able to speak to the hardware and software solutions.
  • At the end of this meeting, you will have your group grade (individual grades will be assigned at a later time).

• Code: Check your documented code into your subversion repository.

  See the code section of project 1 for details.

• Circuit diagram: check your circuit diagram into your subversion repository. This diagram must be developed using EagleCad (see the downloads page).

• Presentation: check a copy of your powerpoint presentation into the subversion repository.

• Personal report: fill out the CATME survey.

Grading

• 35%: Project implementation
• 30%: Demonstration/presentation of working project (to either of the TA or the instructor)
• 35%: Code documentation and group report

Group Grading Rubric

Grades for individuals will be based on the group grade, but weighted by the assessed contributions of the group members to the non-personal programming items.

fagg [[at]] cs.ou.edu

Last modified: Wed Mar 25 23:52:56 2015