AMITY SHOOL OF ENGINEERING AND TECHNOLOGY

FINAL YEAR PROJECT PRESENTATION

PROJECT TITLE – “AIR MOUSE” ACCELEROMETER BASED MOUSE

MENTOR:Dr. Anupama Mehra

By:Devavrat Singh - 174Devdutt Singh - 175Dhruv Sharma - 177Hanish Satija - 184

INTRODUCTION

• We plan to design and construct an accelerometer based mouse which commands the mouse cursor by tilting the palm, so you do not need to rest your hand on any kind of hard surface.

• It consists of a single 3-axis accelerometer: two for position, and one axis for scrolling.

• The mouse communicates to a computer via the PS/2 protocol, or an optional PS/2 to USB converter can be purchased and the mouse can be connected through a USB port.

• Our mouse is OS independent.

• The Air mouse is comfortable to wear, and does not significantly inhibit typing. It functions completely as a two button serial mouse, and even implements variable rate vertical scrolling.

• There have been only two major changes to the mouse since its inception: more buttons, and interface changes (PS/2, USB, Wireless) but the core interaction method has not changed.

• Thus we wanted to take the next step in this technology. For reasons mentioned in the introduction, an accelerometer based mouse system is a great option since:

• It's cool• Provides health benefits

• This is proof that the method of control Tom Cruise had over his computers in the movie Minority Report is not science fiction nor far off in the future.

• The second reason behind this project is the possible health benefits it provides to the user of any computer. The most prevalent injury associated with using a keyboard and mouse is Carpal Tunnel Syndrome.

Why an Accelerometer based Mouse?

• An accelerometer is a sensing element that measures acceleration; acceleration is the rate of change of velocity with respect to time.

• It is a vector that has magnitude and direction.

• Accelerometers measure in units of g – a g is the acceleration measurement for gravity which is equal to 9.81m/s². Accelerometers can measure: vibrations, shocks, tilt, impacts and motion of an object.

What is an Accelerometer?

Applications for Accelerometer

From industry to education, accelerometers have numerous applications. These applications range from triggering airbag deployments to the monitoring of nuclear reactors.

Other practical applications include:• Measuring the performance of an automobile• Measuring the vibration of a machine• Measuring the motions of a bridge• Measuring how a package has been handled

PS/2 Protocol

• The PS/2 mouse interface utilizes a bidirectional serial protocol to transmit movement and button-state data to the computer's auxiliary device controller (part of the keyboard controller). The controller, in turn, may send a number of commands to the mouse to set the report rate, resolution, reset the mouse, disable the mouse, etc. The host provides the mouse with a 5V ~100 mA power supply.

The color-coded PS/2 connection ports (purple for keyboards and green for mice)

Female connector from the front

Pin 1 +DATA Data

Pin 2 Not connected Not connected*

Pin 3 GND Ground

Pin 4 Vcc +5 V DC at 275 mA

Pin 5 +CLK Clock

Pin 6 Not connected Not connected**

Why PS/2? The Trade-offs: 

There are obviously many options for mouse communications protocols, such as serial, PS/2, and USB. There are multiple reasons we chose PS/2 as our standard.

• No prior experience in developing the protocol, unlike RS-232 serial, so it provides for a good challenge for our final project design.

• We could draw power from the PS/2 port, giving our mouse the ability to stand alone without a dedicated power supply or battery.

• PS/2 can be easily adapted to fit USB using a simple adapter. This way we can still get the usability of USB without having to learn the complicated USB standard.

It should be noted however, that there are some downfalls to PS/2 development that may make people in the future decide to program for RS-232 serial. Firstly, PS/2 requires the PC BIOS to detect the mouse and assign a device ID. Unfortunately this process usually occurs at boot up, and may require repeated boot ups of a PC for testing.

Components Used

• ATMEGA16• Microcontroller Programmer• 3 axis Accelerometer • MAX232A • Push Buttons • 5V voltage regulators • Gloves • LM358p Op-Amp• Old Mouse (for PS/2 protocol)

ATMEGA16 MAX232 Microcontroller Programmer

Circuit Diagram

Circuit Schematic for Accelerometer Filtering

Advantages

• Freedom Of Movement – Not restricted only to a desktop or hard surface for use of mouse.

• Health Benefits – Reduces chances of Carpal Tunnel Syndrome• Compatible with almost all PCs following IBM standard and can be incorporated in

laptops using PS/2 to USB connector.

• Detection of Accelerometer Mouse by PC– Can be solved by precise calculation and accurate research of Microsoft PS/2 protocol and

Windows Mouse detection driver process.

• Accelerometer Buffering and Sampling (Level Conversion)– Precautions should be taken such as to assign precise ADC( Analog to Digital ) values for

ATMEGA16 programming.

Challenges and How to Overcome Them

PLAN OF ACTION

To design and construct an accelerometer based mouse using AVR Programming

TASK LIST

Research Microsoft serial mouse protocol: Dhruv Sharma and Hanish Satija

Sampling of parts: Devdutt Singh and Dhruv Sharma

Construction of project-specific circuits: Hanish Satija and Devdutt Singh

Testing: Dhruv Sharma and Devavrat Singh

Initial structure of code: Devavrat Singh and Devdutt Singh

Mouse Protocol code: Devavrat Singh and Hanish Satija

Accelerometer output processing: Devdutt Singh and Devavrat Singh

Presentation and Project Report : Hanish Satija and Dhruv Sharma

Tasks Completed Till Date

• Research of individual parts of project

• Developing test codes

• Hardware implementation on breadboard

• Designing final code for Air mouse

Tasks Yet To Be Completed

• Assembling the final hardware circuit on PCB

• Compiling and Burning test codes on Microcontroller to interface

Accelerometer

• Burning the test codes on microcontroller to interface microcontroller with

PC (computer)

• Burning the final Air mouse code to interface Accelerometer,

microcontroller and PC

The End