GaussStones: Shielded Magnetic Tangibles for Multi-Token Interactions on Portable Displays This work presents GaussStones, a system of shielded magnetic tangibles design for supporting multi-token interactions on portable displays. Unlike prior works in sensing magnetic tangibles on portable displays, the proposed tangible design applies magnetic shielding by using an inexpensive galvanized steel case, which eliminates interference between magnetic tangibles. An analog Hall-sensor grid can recognize the identity of each shielded magnetic unit since each unit generates a magnetic field with a specific intensity distribution and/or polarization. Combining multiple units as a knob further allows for resolving additional identities and their orientations. Enabling these features improves support for applications involving multiple tokens. Thus, using prevalent portable displays provides generic platforms for tangible interaction design. Project Page of GaussStones: http://www.cmlab.csie.ntu.edu.tw/~howieliang/GaussStones.html

1. 2014
GaussStones:
Shielded Magnetic Tangibles for Multi-Token Interactions on Portable Displays
Rong-Hao Liang1,2, Han-Chih Kuo1, Liwei Chan1, De-Nian Yang2, Bing-Yu Chen1
1National Taiwan University and 2Academia Sinica

2. Multi-Token Interactions

3. Multi-Token Interactions

4. Multi-Token Interactions

5. Multi-Token Interactions on Interactive Tabletops
Sculpting and Simulation Boardgaming Live Music Performance
SandScape [Wang et. al. 2010] Lumino [Baudisch et. al. 2010] ReacTable [Jorda et. al. 2007]

6. Multi-Token Sensing Techniques
EMR-Tag Sensing LC-Tag Sensing Active IR-Tag Sensing
SenseTable [Patten et. al. 2001] PICO [Patten et. al. 2007] MightyTrace [Hofer et. al. 2008]

7. Multi-Token Sensing Techniques
EMR-Tag Sensing LC-Tag Sensing Active IR-Tag Sensing
SenseTable [Patten et. al. 2001] PICO [Patten et. al. 2007] MightyTrace [Hofer et. al. 2008]
x x x

8. Multi-Token Interactions on Portable Displays
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VWHP RI DQ DUURZ EHFRPHV ORQJHU WKH IDUWKHU
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Camera(s) Capacitive Touchscreen Magnetometer
Portico [Avrahami et. al. 2011] Capstones [Chan et. al. 2012] MagGetz [Hwang et. al. 2013]
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9. Multi-Token Interactions on Portable Displays
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Camera(s) Capacitive Touchscreen Magnetometer
SandScape [Avrahami et. al. 2011] Capstones [Chan et. al. 2012] MagGetz [Hwang et. al. 2013]
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Occlusion-Sensitive Large size Require Calibration
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10. GaussSense
[Liang et. al. UIST 2012]

11. c d
magnet
GaussSense
[Liang et. al. UIST 2012]

12. c d
magnet
GaussBits
[Liang et. al. CHI 2013]
GaussSense

13. GaussBits
[Liang et. al. CHI 2013]
GaussSense

14. Problem:
Radial Magnetic Field of Each Discrete Tokens
Interferes with Others in Multi-Token Interactions

15. Organic Form Construction
GaussBricks
[Liang et. al. CHI 2014]
GaussBits
GaussSense

16. Multi-Token Interactions Using Discrete Tokens
GaussStones
Shielded Magnetic Tangibles
GaussBricks
GaussBits
GaussSense

17. Solution:
Magnetic Shielding
magnetic shield
magnet

18. UNDERSTANDING
Magnetic Shielding

19. FACT: Electromagnetic (EM) Wave Shielding
is ineffective to block static magnetic fields
FACT: Electromagnetic (EM) Wave Shielding
is ineffective to block static magnetic fields
conductive material
conductive material
Electromagnetic shielding inside mobile phone by Petteri Aimonen
Electromagnetic shielding inside mobile phone by Petteri Aimonen

20. FACT: Electromagnetic (EM) Wave Shielding
is ineffective to block static magnetic fields
FACT: EM-Wave Shielding (a.k.a. Faraday Cage)
is ineffective to block static magnetic fields
provided by
Eddy current
conductive material
Opposing
Field
EM-Wave

21. FACT: EM-Wave Shielding
is ineffective to block static magnetic fields
EM-Wave Static field
conductive material conductive material

22. High-permeability materials
block static magnetic fields by redirecting them
EM-Wave Static field
(e(.eg.g. .g gaallvvaanniziezde sdte eslt)eel)
High-permeability material

23. High-permeability High-permeability materials materials
(e.g. galvanized steel)
block static magnetic fields by redirecting them
EM-Wave Static field
(e.g. galvanized steel)

24. High-permeability High-permeability materials materials
(e.g. galvanized steel)
block static magnetic fields by redirecting them
galvanized steel case
EM-Wave Static field
(e.g. galvanized steel)

25. High-permeability High-permeability materials materials
(e.g. galvanized steel)
block static magnetic fields by redirecting them
galvanized steel case
EM-Wave Static field
(e.g. galvanized steel)
analog Hall-sensor grid

26. Challenge:
Design Challenge:!
Designing Effective Magnetic Shielding that
Designing Effective Magnetic Shielding that can
Minimize Interference and Maximize Signal Strength
Minimize the Interference and Maximize the Signal Strength
galvanized steel case
analog Hall-sensor grid

27. Explorative Study
Finding design
parameters
galvanized steel chip
10mm(T) x 5mm(R)
neodymium magnet
Measurement #1: Interference Strength Measurement #2: Signal Strength

28. Explorative Study
Finding design
parameters
galvanized steel chip
10mm(T) x 5mm(R)
neodymium magnet
Measurement #1: Interference Strength Measurement #2: Signal Strength

29. Explorative Study
Finding design
parameters
galvanized steel chip
10mm(T) x 5mm(R)
neodymium magnet
iso-intensity contours (for every 10 gauss)
Measurement #1: Interference Strength Measurement #2: Signal Strength
Measurement #1: Interference Strength Measurement #2: Signal Strength
Measurement #1: Interference Strength Measurement #2: Signal Strength

30. Explorative Study
Finding design
parameters
galvanized steel chip
10mm(T) x 5mm(R)
neodymium magnet
iso-intensity contours (for every 10 gauss)
Measurement #1: Interference Strength Measurement #2: Signal Strength
Measurement #1: Interference Strength Measurement #2: Signal Strength
Measurement #1: Interference Strength Measurement #2: Signal Strength

31. iso-intensity contours (for every 10 gauss)
Measurement #1: Interference Strength Measurement #2: Signal Strength
1000 samples

32. Area-Intensity Profile
Measurement #1: Interference Strength Measurement #2: Signal Strength
Measurement #1: Interference Strength Measurement #2: Signal Strength
contour size
N S S
iso-intensity contours (for every 10 gauss)
Blob size per layer
Area-Intensity Profile
intensity
iso-intensity contours (for every 10 gauss)
1000 samples
Measurement #1: Interference Strength Measurement #2: Signal Strength
contour size
intensity
Blob size per layer
Area-Intensity Profile
1000 samples

33. No Bottom Sides Sides Sides Sides Sides Sides Sides
15 15 15 9 12 15 15 15 15
2 2 2 2 2 1.2 3 2 2
0 0 0 0 0 0 0 2.5 5
shielding method
token width (mm)
Results 1/4: Shielding methods
No Sides Bottom
shield thickness (mm)
magnet z-axis position (mm)
Measurement #1: Interference Strength Measurement #2: Signal Strength
Results 2/4: Gap Distances (mm)
2 3.5 5
Measurement #1: Interference Strength Measurement #2: Signal Strength
Results 3/4: Shield Thickness (mm)
1.2 3 2
Measurement #1: Interference Strength Measurement #2: Signal Strength
Results 4/4: Magnet Positions
5 2.5 0
Measurement #1: Interference Strength Measurement #2: Signal Strength

34. galvanized
steel shield
neodymium
magnet
Findings:
Basic Design:
Fix magnet at the center bottom
with shielding on the sides to
minimize the Interference and
maximize the Signal Strength

35. Findings:
Basic Design:
Fix magnet at the center bottom
with shielding on the sides to
minimize the Interference and
maximize the Signal Strength
Shield Thickness: Thicker is better,
but just-thick-enough is the best.
1.2mm-thick 3mm-thick

36. Findings:
Results 2/4: Gap Distances (mm)
Basic Design:
Fix magnet at the center bottom
with shielding on the sides to
minimize the Interference and
maximize the Signal Strength 0 100
Shield Thickness: Thicker is better,
but just-thick-enough is the best.
Token size:
Larger token has larger ID space
Acceptable signal
strength for both
shielding and sensing
2/4: Gap Distances (gauss)
9mm
Measurement #1: Interference Strength Measurement 2 3.5 5
15mm
Measurement #1: Interference Strength Measurement #2: Signal Strength
2 3.5 Results

37. DDeessigignniningg G GaauussssSStotonneess i nin D Dififfeferreenncte S Sizizeess
Particles Tokens Knobs

38. DDeessigignniningg G GaauussssSStotonneess i nin D Dififfeferreenncte S Sizizeess
Particles Tokens Knobs
Tokens without ID
(x,y)

39. Particles (7.8mm-radius, 6g) Shield: 2mm-thick
Magnet: 2mm-radius

41. DDeessigignniningg G GaauussssSStotonneess i nin D Dififfeferreenncte S Sizizeess
Particles Tokens Knobs
Tokens without ID Tokens with ID
(x,y) (ID,x,y)

42. ID amount: 2
N
S

43. Using Larger Particles as Tokens
ID amount = 2 ID amount = 4 ID amount = 6x2 = 12
8.6
1.2
2 1.5 1.5 2
N S
12.5 15
2
1.5 2 2.5 3 3.5 2 x 2
S
Token radius
Shield thickness
Magnet radius
Polarity
7.8
2
2
N S
Larger Particles Provide More IDs
(Unit: mm)

44. Using Larger Particles as Tokens
Using Larger Particles as Tokens
ID amount = 2 ID amount = 4 ID amount = 6x2 = 12
ID amount = 4 ID amount = 6x2 = 12
8.6
1.2
2 1.5 1.5 2
N S
12.5 15
2
1.5 2 2.5 3 3.5 2 x 2
S
Token radius
Shield thickness
Magnet radius
Polarity
7.8
2
2
N S
Larger Particles Provide More IDs
(Unit: mm)
8.6
1.2
1.5 1.5 2
N S
12.5 15
2
1.5 2 2.5 3 3.5 2 x 2
S
Area-Intensity
Profiles

45. Using Larger Particles as Tokens
Using Larger Particles as Tokens
ID amount = 2 ID amount = 4 ID amount = 6x2 = 12
ID amount = 4 ID amount = 6x2 = 12
8.6
1.2
2 1.5 1.5 2
N S
12.5 15
2
1.5 2 2.5 3 3.5 2 x 2
S
Token radius
Shield thickness
Magnet radius
Polarity
7.8
2
2
N S
Larger Particles Provide More IDs
(Unit: mm)
8.6
1.2
1.5 1.5 2
N S
12.5 15
2
1.5 2 2.5 3 3.5 2 x 2
S
Area-Intensity
Profiles

48. DDeessigignniningg G GaauussssSStotonneess i nin D Dififfeferreenncte S Sizizeess
Particles Tokens Knobs
Multi-core Tokens
with ID
Tokens without ID Tokens with ID
(x,y) (ID,x,y) (ID,x,y,θ)

49. Knobs - Multi-Core Tokens
1.2
2 1.5 1.5 2
Provide additional IDs and Orientation Information
N S
2
1.5 2 2.5 3 3.5 2 x 2
S
2
2
S
0 1 2 3
Using Larger Particles as Tokens
8.6
1.2
2 1.5 1.5 2
N S
12.5 15
2
1.5 2 2.5 3 3.5 2 x 2
S
7.8
2
2
S
ID amount = 4 ID amount = 6x2 = 12

50. Knobs - Multi-Core GaussStones
Provide additional IDs and Orientation Information
north
south
Dual-Core Tri-Core Quad-Core
B0 B3
B1 B2
Registration
Payload
2.16R 2.41R
2R
B0 B1
B0 B2
B1
R
1.2
2 1.5 1.5 2
N S
2
1.5 2 2.5 3 3.5 2 x 2
S
2
2
S
0 1 2 3
(x,y,θ)
Dual-Core
Tri-Core
Quad-Core
2.16R
2R
2.41R

51. Knobs - Multi-Core Tokens
Provide additional IDs and Orientation Information
north
south
Dual-Core Tri-Core Quad-Core
B0 B3
B1 B2
Registration
Payload
2.16R 2.41R
2R
B0 B1
B0 B2
B1
R
1.2
2 1.5 1.5 2
N S
2
1.5 2 2.5 3 3.5 2 x 2
S
2
2
S
0 1 2 3 (x,y,θ)
(ID)

52. 1.5 2 2.5 3 3.5 2 x 2
north
south
Dual-Core Tri-Core Quad-Core
B0 B3
B1 B2
Registration
2.16R 2.41R
2R
B0 B1
B0 B2
B1
2
S
R
1.2
2 1.5 1.5 2
N S
Payload
[3,2,2] [3,2,1] [3,2,0] [3,1,2] [3,1,1] [3,1,0] [3,0,2] [3,0,1] [3,0,0] [2,1,1] [2,1,0] [2,0,1] [2,0,0] [1,0,0]
2
2
S
0 1 2 3 (x,y,θ)
(ID)
[3,2] [3,1] [3,0] [2,1] [2,0] [1,0]
Dual-Core
Tri-Core
Knobs - Multi-Core Tokens
Provide additional IDs and Orientation Information

55. ID amount of a k-core knob grows exponentially
ID amount of a k-core knob grows exponentially
with the core number and the ID amount that a core can provide
with the core number the core ID amount
6
15
28 45
14
55
140
285
36
225
784
2025
10000
1000
100
10
1
4 6 8 10
2 3 4 5
ID amounts
Available ID amounts that a core can provide
ID amount that a core can provide
ID amount of a k-core knob:
ID amount of a k-core knob
with the number and size of core
1.7mm-radius
3.5mm-radius

56. Possible Generalizations
2. Multi-Part Widgets with ID
1. Stackable Tokens

57. Stackable Token
(Particles with 2 IDs)

58. Stackable Token
(Particles with 2 IDs)

59. Multi-Part Slider
ID part
Movable part
Multi-Part Widgets
(with IDs)

60. ID part
movable part
(Conductive)
Multi-Part Widgets
(with IDs)

61. Conclusion
Interference-Free Identifiable Shielded Magnetic Tangibles
for Multi-Token Interactions on Portable Displays
GaussStones
Shielded
Magnetic Tangibles
Project website
Discrete Tokens
Multi-Token Interactions
GaussSense Magnetic Field Camera

62. Discrete Tokens
Multi-Token Interactions
GaussStones
Shielded
Magnetic Tangibles
Organic Form
Constructive Interactions
GaussBricks
Single Token
Near-Surface Interactions
GaussSense Magnetic Field Camera
Magnetic
Building Blocks
GaussBits
Magnetic
Tangible Bits
Project website
Project Gauss
A system of Hardware, Materials, and Interaction Techniques
that Turn Portable Displays into Generic TUI Design Platforms

63. Project Gauss
A system of Hardware, Materials, and Interaction Techniques
that Turn Portable Displays into Generic TUI Design Platforms
Free-license for Personal Non-commercial Uses
Discrete Tokens
Multi-Token Interactions
GaussStones
Shielded
Magnetic Tangibles
Organic Form
Constructive Interactions
GaussBricks
Single Token
Near-Surface Interactions
GaussSense Magnetic Field Camera
Magnetic
Building Blocks
GaussBits
Magnetic
Tangible Bits
Project website
Rong-Hao Liang1,2, Han-Chih Kuo1, Liwei Chan1, De-Nian Yang2, Bing-Yu Chen1
1National Taiwan University and 2Academia Sinica Thanks for your attention!