Objective was to utilize SunSPOT Sensor
Technology to implement a conventional
mouse or a similar I/O device.
The only difference would be it does not
require to be intact with a surface.
Three possible approaches according to our analysis:
#1. Wire the conventional mouse with SunSPOT sensor
The union of the two would be in such a way that the
conventional mouse would be dismantled and the
physical circuit pins of the mouse would be wired to
the circuit pins of the SunSPOT.
Possible Approach # 1 (Cont.)
The sensor would then be programmed to
gather and interpret the movement and actions
of the conventional mouse.
Possible Approach # 2
The second of the possible approaches is to
use the SunSPOT sensor on its own
The sensor would be communicating without a
The sensor would then be acting in a more
conventional way via its direct connection through
the USB port
Possible Approach # 3
The third approach involves the use of the
SunSPOT base station as a communicator
between the SunSPOT sensor mouse and the
The sensor mouse would communicate to the
base station which would then relay the given
information to the local machine.
The result would then be a mouse that would be
held in the hand and communicate to the base
station and CPU remotely.
Approach # 3 was more feasible to implement
Resources were available for this approach
Consistent communication with Sun Certified for IDE
Research Assistant, Sensing Ubiquity Mobility Research
University of Melbourne, Australia
GetSunSPOT tilt data from accelerometer, and
send it back to host PC via the base station
Host PC translates these coming data to a Java
Robot class which emulates mouse movement.
Selected Approach (Cont.)
The use of the incorporated accelerometer enables the
sensor mouse to move along three axis (X, Y & Z),
instead of the traditional two axis mouse
The two momentary switches can be utilized as the left
and right click buttons of a traditional mouse.
The use of radio communication allows the
sensor mouse to be detached and able to
operate at a greater distance than a traditional
The ability to stand a greater range away from
the CPU and maintain accurate control over
on-screen pointer is a unique approach made
possible by the SunSPOT sensor’s micro
Through out this project there were many
obstacles to overcome.
The first of which was to understand how a
conventional mouse functioned.
Obstacles - Conventional
A conventional mouse can use optical or laser
technology to orient it self and be hardwired to
the CPU or use radio frequency to
The second necessity was to understand the
Sun SPOT sensor and its capabilities.
The SunSPOTs come equipped with a light
sensor, temperature sensor and an
The sensors use radio frequency to communicate
to the base station that is connected via USB port
to the CPU.
Thus, the sensors are capable of having a free
The SunSPOT and base station needed to be
programmed in Java to function as a mouse.
Most of the work is in the interpretation of the
coordinates that are gathered by the
accelerometer already in the sensor.
Again, there is an added element of the z-axis to
the mouse concept which can have unpredictable,
but interesting consequences.
The function of the two push buttons/switches on
the sensors were required to be functioned as the
right and left click.
The first attempts at troubleshooting the test
model were almost successful.
The sensor mouse was found to be very
sensitive to the slightest motion and had a
tendency to drift when not in use or being held.
Overall, the mouse required the user to get
used to using a mouse in a more interactive
The user could compensate for the Sun
SPOTs sensitivity by holding in the hand and
using controlled movement during use.
Because of the extreme sensitivity of the mouse is
so acute, there could be complications if there were
any other operational SunSPOT sensors or devices
on the same radio frequency within range of the
To avoid that, we forwarded the port and IP address
of the sensor to base station for accuracy.
The SunSPOT sensor mouse was found to be
fully functional in a conventional mouse
The sensor mouse was held in the hand and
moved according to the direction of motion
from the user’s hand.
It was found to be easier and more accurate to
direct the pointer by holding the mouse in a
way that put the sensor mouse in front of the
screen and move the mouse exactly as the
pointer was desired to be moved.
Final Result (Cont.)
This set up was able to be carried out with the
user sitting a few feet away from the CPU and
screen although close enough for the user to
be able to read the screen.
The two push buttons/switches on the sensors
were fully functional.
They correlated as they should with the
buttons for left and right click options.
The sensor mouse in this project met the
objective as a functioning mouse.
The left and right click functions are
operational and the pointer is controlled via the
The mouse exceeded expectations in the
added bonus of being able to function with out
a need for a given space to work on.
It is a true wireless mouse working in a free
The added mobility of being able to function
without wires and within a greater working range
The areas in which it falls short are in its need to
be held and lack of scrolling capability.
The sensor mouse when used on a flat surface
has a tendency to be unresponsive and just drifts
the pointer on screen.
For a more optimum function, the user must hold
the unit in the air in such a way that the user’s
hand must motion in the direction that the pointer
is desired to move in.
The lack of the ability to scroll is a major drawback
for users viewing large documents or surfing the
Another hindrance for this sensor mouse is the
crosstalk that can render this sensor mouse very
Any other operating SunSPOTs in the vicinity of
the project during testing caused the mouse to act
Research Assistant, Sensing Ubiquity Mobility Research Lab
CSSE Dept. University of Melbourne, Australia
Software Engineer, Daintree Networks