* DAC 2001

  won the First Prize in the "Conceptual Category" !

Seungbae Lee, Gi-Joon Nam, Junseok Chae, and Hanseup Kim

Abstract

The design of a hybrid two-dimensional position sensing system for MOUSE applications is described. The selected system incorporates four major components: 1) MEMS accelerometers, 2) CMOS analog read-out circuitry, 3) an acceleration magnitude extraction module, and 4) a 16-bit RISC. The MEMS accelerometer exhibits both horizontal and verical deflection to enable sensing of acceleration. The CMOS analog circuitry and RISC digital circuitry modulate and convert the acceleration into two-dimensional location coordinates by double integration. Performance of the suggested system was simulated by the MENTOR Graphics software. The final design with a dimension of 5.8 mm by 10.2 mm, shows that the minimum detectable acceleration is 5.3 mg, and thus it is applicable to mouse system.

Targets

• Design the padless position detecting system.
• Integrate MEMS device, analog interface circuit and digital micro processor.
• Verify the functionality of the total system.
• Suggest an appropriate fabrication technology for the system.

Outcomes

• The correct functional operation was achieved in each system block.
• The expected minimum detectable acceleration is 5.3 mg, which is fit for human hand movement detection.
• The designed analog circuit has the size of 4.5 mm by 2.6 mm and the estimated power of 3 mW.
• The core control microprocessor incorporates 53634 transistors and the achievable clock speed is 18.1 MHz.
• The power consumption of the digital processor is estimated as 10 uW at 100KHz operating frequency.
• The SOI technique is suggested for fabricating the padless MOUSE system which has final dimensions of 5.8 mm by 10.2 mm with 3.1 mW as total power consumption.

Brief description

 

Backgrounds

1. MEMS Accelerometer Structure

2. Fabrication Process

3. Electromechanical Modulator

4. Noise Calculation

5. Microprocessor

6. SOI

Conclusion

A novel hybrid two-dimensional position sensing system for padless MOUSE has been successfully proposed, designed and verified. The system functionality was simulated using the MENTOR Graphics suite, and testing results indicate that minimum detectable aceleration is 5.3 mg, which is fit for human hand movement detection. The designed analog circuit has the size of 4.5 mm by 2.6 mm and the estimated power of 3 mW. The core control microprocessor incorporates 53634 transistors and the achievable clock speed is 18.1 MHz. The power consumption of the digital processor is estimated as 10 uW at 100KHz operating frequency. The major four components: 1) MEMS accelerometers, 2) CMOS analog read-out circuitry, 3) an acceleration magnitude extraction module, and 4) a 16-bit RISC microprocessor can be fabricated using SOI technique, which has final dimensions of 5.8 mm by 10.2 mm with 3.1 mW as total power consumption. The overall size and performance characteristics of this two-dimensional position sensing system using MEMS accelerometer is appropriate for use in a padless MOUSE system.

Future Challenge

Based on the design of the hybrid two-dimensional position sensing system for MOUSE applications described in this project, several future applications are considered.

• A THREE DIMENSIONAL MOUSE SYSTEM : If another MEMS accelerometer is added for detecting the z-direction movements, the revolutionary three dimensional mouse system can be achieved. The novel system can be used as a 3D structure CAD design or virtual reality system.
• A WIRELESS PERSONAL MOUSE SYSTEM : Additional wireless communication system of the MOUSE to computer makes it possible for people to bring personal MOUSE. It eliminates the necessity of sharing public MOUSE , for example, in library or computer lab.. On top of that, during the seminar or class, every participants can freely and easily access the screen by using each one's MOUSE to the same computer screen.

Researchers

Seungbae Lee: Solid State Electronics Laboratory, University of Michigan. [seungbae@engin.umich.edu]

Gi-Joon Nam: Advanced Computer Architecture Laboratory, University of Michigan. [criteria@engin.umich.edu]

Junseok Chae: Solid State Electronics Laboratory, University of Michigan. [jchae@engin.umich.edu]

Hanseup Kim: Solid State Electronics Laboratory, University of Michigan. [hanseup@engin.umich.edu]

Related destinations of interest

University of Michigan EECS

Center for Wireless Integrated Microsystems (WIMS)

Design Automation Conference (DAC)

Solid State Electronics Laboratory (SSEL)

Advanced Computer Architecture Laboratory (ACAL)