Battery ry-Free Id Identifi fication Token for Touch Se Sensing Devices Phuc Nguyen , Ufuk Muncuk, Ashwin Ashok, Kaushik R Chowdhury, Marco Gruteser, and Tam Vu
Phone & Laptop Existing touch surfaces serve as an interface between Smart vehicle Home security human and the devices itself Touch Sensing Technology Can an object interact with the touch surface? Medical Devices Payment Smart appliances
Collaborative Applications 01 User ID Logging 001 Windows design 002 Front door design 001 Roof design 002 Roof coloring 001 Back yard design 002 Back door design 02 … … Associating user ID to collaboration activities
Gaming Applications with Touchscreen There is a need for associating identity to touch interactions Multiplayer Games Role-playing Games Associating real-world token to digital world
System Overview Artifact Token Transmitter Touch Surface Receiver Idea: Send data (e.g. Identifier) to the mobile device by varying capacitance on the of touch surface
Transmitter Design Touch-enabled device Artifact Capacitance Token 0 Time Micro-controller Control switch to (token ID encoded as bits) vary capacitance
Modulation ‘0’ ‘0’ ‘1’ ‘0’ ‘0’ ‘1’ ‘1’ ‘1’ Capacitance 0 1 2 5 6 7 3 4 8 Time slot How do we vary capacitance efficiently?
Capacitance Touch surface Time t press t prob t prob Touch sensor Objective: min(t press - t prob) How do we obtain t prob ?
Enable th the token to profile th the touch surface
Probing Frequency ( f prob = 1 / t prob )
Finding Probing Frequency • Autocorrelation is used to find probing frequency t prob t prob
Finding Probing Frequency Probing frequency (Hz) 130.04 140 124.52 118.8 120 109.8 108.16 103.62101.2 100 96 100 84.33 80 62 62.36 60 40 20 0
Receiver Design Touch-enabled device Artifact Token Touch Events XY Touch Pointer ID Touch size Event Type Timestamp coordinate Amplitude • Down Time in ms Touch’s location • Up • Move
Harvesting Energy fr from Touch Surfaces
Energy Harvesting ADC reading
Challenges Flicker noise 0 – 100 Hz
Proposed Approach
Energy Harvesting Module D 2 C 1 Micro- controller Band Pass Filter C S D 1 C 2 Storage Electrode (F cut-off, Capacitor Bandwidth) Rectifier Touch sensor Harvesting Module 2"
Prototype Im Implementation
Detection Rate Goal: Evaluate the object identification accuracy Experiment: Calculate token detection rate (fraction of total number of times the token is correctly identified)
Power Consumption Goal: Evaluate the power consumption Experiment: Calculate the energy consumption when sending data at different size Power ~ time to open & close switch
Im Impact of f Profiling Technique Goal: Evaluate the impact of profiling technique Experiment: Calculate event generation rate between our approach and strawman approach
User Study
Conclusion 1. Associating IDs to tokens for touch interactions 2. Enabling the token to profile the touch surface 3. Harvesting energy from the touch surfaces
Battery ry-Free Id Identification Token for Touch Sensing Devices Phuc Nguyen , Ufuk Muncuk, Ashwin Ashok, Kaushik R Chowdhury, Marco Gruteser, and Tam Vu
Recommend
More recommend
