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Exciting Physics With Android Devices. An effective measuring system in your hands: Sensors embedded in mobile phones or tablets Measuring program (Java and Android SDK ). Methodology: Active Learning, Inquiry Based Classes. Measure. Guided Inquiry Method. Ask questions. - PowerPoint PPT Presentation
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Sándor Egri, Hungary, University of Debrecen,
Institute of Physics, [email protected]
u An effective measuring system in your hands:-Sensors embedded in mobile phones or tablets-Measuring program (Java and Android SDK)
Methodology: Active Learning, Inquiry Based Classes
Ask questions
Measure
Analyze your data
Discuss
Guided Inquiry
Method
18
16
14
12
10
8
6
4
2
0
-2
Ver
tical
Acc
eler
atio
n (m
/s2 )
1211109876543210Time (s)
12
10
8
6
4
2
0
-2
-4
-6
-8
-10
Coo
rdin
ates
of a
ccel
erat
ion
(m/s
2 )
64626058565452504846Time (s)
tangential centripatal vertical to the plane of the phone
15
10
5
0
-5
-10
Coo
rdin
ates
of a
ccel
erat
ion
(m/s
2 )
113x103
112111110109108Time (s)
centripetal tangential vertical to the plane of the phone
Dumping oscillations of a cart.
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
Acce
lera
tion
(m/s
2 )
2423222120191817161514131211109876543210Time (s)
Measured data (hollow circles) fit well with results of calculation (solid line)
Rotation of a disc in a vertical plane : experiment at home
High frequency
Low frequency and pendulum
Range: -20 m/s2 - +20 m/s2
Resolution: 0,04 m/s2
Accuracy::Maximum error app.. 0,3m/s2
SD=0.07 m/s2
Acceleration sensor example
A simplified working principle
Calibration of the sensor: g=9,81m/2 precise value for Hungary
Standing with mobile in the hand, legs are
bent. Measured acceleration = g
Quick stretching of the legs. Acceleration: up
Freefall, measured acceleration =0 m/s2
Braking the fall.
Measured acceleration is proportional with the net force (without gravity) acting on the device.
Jumping with mobile phone
Exciting Physics With Android Devices
Mobile is lying on a horizontal plane, Number of data: 600Display is facing up: a_z=9,781, SD_avg=0,003 (m/s2)Display is facing down: a_z=9.639, SD_avg=0,004 (m/s2)Absolute Mean value: 9,735 (m/s2), SD=0,005 (m/s2) Relative error: 0,8%
name quantity max f type
acceleration acceleration caused by forces excluded gravity
200Hz real
gyroscope angular speed of turning
200Hz real
magnetic field
magnetic induction vector
200Hz real
ambient light
Luminous intensity, changing
changing real
linear acceleration
200Hz virtual
gravity 200Hz virtual
Other possibilities for physics
-Creation of electric signals (audio output)-Detection of sound (audio input, microphone)-Camera, image processing
and others, like proximity, GPS …
The quickest way of learning something is doing it.
