Accelerometer Sensor
Accelerometers are used to sense both static, dynamic acceleration and is used more widely for ‘tiltsensing’. They are affected by the acceleration of gravity. Hence, an accelerometer can tell you the
acceleration relative to ‘freefall’ (when an object is falling). This feature is applied in several hard
drives. And if a drop is sensed, the hard drive is quickly turned off to protect against the loss of data.
It is also used to sense motion. An example is seen in the Nintendo ‘Wii’ controller. It can be used to
sense movement of forehands and backhands of a tennis racket, or rolls of a bowling ball.
How the sensor works;
An accelerometer acts as a motionless mass on a spring.
When the accelerometer is caused to move, the mass inside
the casing will be altered. The altered mass is then
measured by a piezoelectric, piezo-resistive, or capacitive
device which converts the mechanical movement of the mass
inside the cases into an electrical signal to give the
acceleration.
Current Applications;
Accelerometers are used in a variety of applications. Some of
these applications consist of measuring car acceleration,
heavy
machinery,
electronic
consumer
devices,
and
architectural applications. Apple's Iphone and other smartphone products have an accelerometer, which lets it know whether it's being held
upright or sideways. Within the architectural realm, the accelerometer (high
sensitive sensor version) is used to monitor the movement of a building and also
monitors human movement within the building. They are also widely consumed for
game consoles, for example the Nintendo Wii and the Play station 3.The
accelerometer within the game controller detects motion, which is then transferred
to motion/movement within the game
Interfacing To an Arduino;
An abundance of accelerometers are capable of interfacing with the
Arduino micro controller. There are those with single axis, rising
up to 6-axis accelerometer sensors. The new PlayStation 3, for
example, uses a 6-axis accelerometer within its controller. It aims
to re-create a real driving experience by steering completely by
movement. When these sensors are combined to the Arduino, they can
control variables and outputs. There is an Analog interface that is
used for this particular sensor. The Analog output will produce a
voltage
that
is
directly
proportional
to
the
sensed
acceleration. Generally this interface is the easiest to work with
and is implemented in most microcontrollers to allow data to be
transmitted. To connect the Accelerometer to the Arduino board (in
this case we are connecting the sensor to the basic Arduino board;
‘Arduino Duelmilanove’. There are pins on the Accelerometer.
Depending on the number of axis pins you have (single-axis, 3-axis,
6-axis etc), will result to where you connect the pins. These pins
are inserted into the Aduino board described from the diagram to the
left. Once connected, and movement occurs, the sensors transmit
information to the Arduino and allows the Arduino to recognise what
movement is occurring.
Angelica Lov
S3236897
Current Projects;
-
Using the accelerometer to control the movement of a toy car.
http://www.youtube.com/watch?v=gcRuuZH3TNA&feature=player_embedded
-
How to use an use an accelerometer as a mouse.
http://www.uchobby.com/index.php/2007/10/27/accelerometer-based-mouse/
References;
Accelerometer, Wikimedia Foundation, Inc., viewed on 16th August 2010
http://en.wikipedia.org/wiki/Accelerometer
Dual Axis Accelerometer Breakout Board - ADXL213AE +/-1.2g, © SparkFun Electronics, Boulder, Colorado, viewed on 16th August 2010
http://www.sparkfun.com/commerce/product_info.php?products_id=843
3-Axis Accelerometer Module, Modern Device, viewed on 17th August 2010
http://www.moderndevice.com/products/mma7260qt-3-axis-accelerometer
Using an Accelerometer to Sense Which Way Is Up, code, circuits, & construction, viewed on 18th August 2010
http://www.tigoe.net/pcomp/code/category/arduinowiring/216
Hardware-Sensors, Physical programming, viewed on 17th August 2010
http://www.openobject.org/physicalprogramming/Hardware-Sensors
A beginner’s guide to accelerometers, Dimension Engineering LLC, viewed on 18th August 2010
http://www.dimensionengineering.com/accelerometers.htm
Images;
http://www.acu-vib.com.au/accelerometers.htm
http://www.moderndevice.com/products/mma7260qt-3-axis-accelerometer
http://www.moderndevice.com/products/arduino-duemilanove