Hi, this is Rong-Hao from TU Eindhoven. I’m presenting this paper entitled
combining touchscreens with passive rich-ID building blocks,
to support context construction in touchscreen interactions.
This is a joint work of National Taiwan University and TU Eindhoven.
Passive rich-ID building blocks, RFIBricks, were recently proposed to support the interactive
semantic construction of digital information. Based on UHF RFID sensing, these blocks provide
battery-free, wireless, non-line-of-sight sensing of virtually unlimited IDs,
making the deployment and maintenance easy when at scale.
However, Interacting with these blocks often relies on stacking operations,
which are discrete and effortful. Also, since they are passive,
they rely on an external display to show dynamic visual feedback.
In this paper, we research through exploring the design space of combining touchscreens
with passive rich-ID building blocks. We realized two conceptual systems:
Constructive assemblies, and a stackable touchscreen to proof the concepts.
With constructive assemblies, RFIPillars, the users can define the touch interaction
context through stacking these semantic building blocks on the base stations.
The users can also expand the interaction space by connecting the portable stations
like performing 2D stacking using these tangibles. With a stackable touchscreen system, RFITiles,
the users can first upgrade the mode of inputs through stacking the rich semantic cards,
and then trigger the effect on the target through a touch on the stack.
Moreover, the users can perform rich touch interactions through the stack of cards,
such as using a widget and performing gestures.
This exploration expanded the knowledge of HCI with the rich-ID building blocks.
Both systems support direct and lightweight touchscreen interactions,
while keeping the tangibles passive.
We also bring the stacking capabilities to the RFID approach,
which is more efficient in ID encoding than other sensor-based solutions.
We implemented the two systems based on the same philosophy.
The touchscreen integration intentionally keeps the rich-ID tangibles passive.
In RFIPillars, we leverage the lens and mirrors in the cubes to pass the rear-projection up,
and use a capacitive touch sensing matrix to pass the touch event down
to the active stations for signal processing.
In RFITiles, we create thin-form transparent cards and tiles covered by a
capacitive touch sensing matrix,
and detect touch inputs using the active tiles on the projection surface.
Both systems used a stacking sensing mechanism that is similar to the RFIBricks,
but their UHF tag antenna designs are different from RFIBricks due to their form factors.
For both systems, we evaluated their basic stacking and touch input capabilities,
in terms of stacking sensing, touch latency vs.
accuracy and the display quality after stacking. The results show they both provide enough
performance to support the operations in the proposed interactions, yet both are limited.
Now, we revisit the scalability in the passive approach regarding the RFIPillars system.
The passive tangibles are cheaper than the active
tangibles because they are made of passive materials.
The extra costs of the external sensing system pay off when the systems have more passive tangibles.
Using a cheaper electronic-based stacking sensing system could further reduce the cost.
On the other hand, RFITiles is more scalable than the RFIPillars,
because the tangibles are simpler and the entire tile grid shared a single display.
However, unlike RFIPillars, RFITiles provides less support on constructive assemblies' applications.
We also provide preliminary results to inform future development and generalization,
such as supporting the rotation operation and more displays,
increasing touch input resolution and types, and improving the visual quality after stacking.
In the paper, we also discussed the preliminary user experiences of the current systems.
Summary, our main contributions of this paper are the realization of a novel interaction system
and the knowledge created through the technical design,
which could increase our understandings in the solutions of reconfigurable touchscreen designs.
For more information about the Rich-ID Interactivity project,
please check our website. Thanks for watching!