Kionix low-g acceloreometers used as tilt-sensor. Link here (PDF)
Accelerometers have countless potential tilt-sense applications in today’s motion-enabled world. Tilt-sensing opportunities exist in a variety of industries, such as automotive, consumer electronics and military/aerospace, and include:
• Vehicle stability systems
• Cell phone/PDA screen navigation
• Motion-enabled game play
• Tilt-enabled computer mouse/pointer
• Tilt-compensated electronic compass
Some of these applications currently utilize dual-axis accelerometers that, at times, are adequate for the job. A tri-axis accelerometer, however, can enable additional functionality, accuracy and precision.