from: Wiimote
The motion of the remote is sensed by a 3-axis linear accelerometer located slightly left of the large A button. The integrated circuit is the ADXL330 (data sheet), manufactured by Analog Devices. This device is physically rated to measure accelerations over a range of at least +/- 3g with 10% sensitivity.
Inside the chip is a small micromechanical structure which is supported by springs built out of silicon. Differential capacitance measurements allow the net displacement of the tiny mass to be converted to a voltage, which is then digitized. It is important to note that the sensor does not measure the acceleration of the Wiimote, but rather the force exerted by the test mass on its supporting springs. Due to the sign convention used, this quantity is proportional to the net force exerted by the player's hand on the Wiimote when holding it. Thus, at rest on a flat table, the accelerometer reports vertical force of +g (the mass can be normalized away into the aribitrary units), and when dropped reports a force of nearly zero
Accelerometers from SparkFun:
http://www.sparkfun.com/commerce/categories.php?cPath=23_80
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Triple Axis Accelerometer Breakout - ADXL330
Price: $29.95
Description: Breakout board for the 3 axis ADXL330 from Analog Devices. This is the latest is a long, proven line of Accelerometers from Analog - and now the holy grail has finally arrived. The ADXL330 is a triple axis accelerometer with extremely low noise and power consumption - only 320uA! Sensor ranges from +/-3g. Board comes fully assembled and tested with external components installed.
Dimensions: 0.7x0.7"
Documents:
* ADXL330 Data Sheet
* ADXL3xx Schematic
* Example 3D cube project using a PIC
Interface: The ADXL330 is a 3V part and outputs an analog voltage for each of the three outputs. This voltage is in ratio to the measured acceleration and to the supply voltage (ratiometric). You will need some extra hardware to convert this analog signal to a usable digital one. Luckily, many uCs have a built in Analog to Digital converter.
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Hitachi H48C Tri-Axis Accelerometer Module
Price: $39.95 PARALLAX
see documentation at link.
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A cheap and elegant way to "fake" a real Accelerometer
Piezo Film Vibra Tab Mass
Price: $1.79
Weight: 0.01 lb.
Piezo Film Information (.pdf)
Piezo Film Vibra Tab Datasheet (.pdf)
Piezo Film Trigger Source (.bs2)
General Description
This Piezo Film Vibra Tab Sensor is the LDT0 Solid State Switch/Vibration Sensor manufactured by
Measurement Specialties. The LDT0 is a piezoelectric film device capable of acting as switch or vibration
sensor. Characteristics of this device allow even more possibilities for use.
Features
• Wide range of applications
• Thin polymer film laminate with 2 crimped contacts
• Easy interface to BASIC Stamp® and SX Microcontrollers
• Can be read using PULSIN, COUNT or by reading input pin level
Application Ideas
• Alarm System Sensor
• Product Damage/Shock Detector
• Accelerometer
• Tap Switch
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http://www.pyrofersprojects.com/3dcube.php
ADXL330 + FLASH + Arduino
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