Tactile Feedback for Mobile Interactions

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Tactile Feedback for Mobile Interactions

• Chris Dufresne

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Overview

• Entering text on small soft key keyboards can be
  problematic
• Especially when mobile
• Compared standard soft keys against soft keys
  with tactile feedback

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Study Details

• Text Entry Problems Analyzed
• Wrong letters
• Slips
• Double Taps
• Conducted in lab and on train
• Within subjects design
• Stylus Based

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Results

• Tactile interface improved
• Amount of text entered
• Numbers of errors made
• Correction of errors made
• Lab
• 22.4 more errors without tactile
• 48.3 more errors corrected
• Mobile
• 25.7 more errors without tactile
• 66.9 more errors corrected
• Higher perceived performance

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Follow-up Research

• Investigating the Effectiveness of Tactile
  Feedback for Mobile Touchscreens (CHI 2008)
• T-Bars Towards Tactile User Interfaces for
  Mobile Touchscreens (MobileHCI 2008)

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Tactile Feedback for Mobile Touchscreens

• Finger-based text entry VS physical keyboard
• Modeled different events
• Fingertip-Over
• Home Keys (F, J)
• Fingertip-Click (button press)
• Fingertip-Slip

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Tactile Feedback for Mobile Touchscreens

• 12 participants
• 3 female, 9 male
• 2 Experiments
• Metrics
• Accuracy
• Keystrokes per character
• Time to enter phrases
• Subjective workload

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Experiment 1 Lab and Mobile

• Accuracy
• 88.25 in lab VS 89.6 mobile w/physical
• 82.7 in lab VS 80 mobile w/tactile
• 69.6 in lab VS 65.8 mobile w/o tactile
• Keystrokes per Character
• Physical had fewest
• Standard softkey keyboard had fewer than softkey
  keyboard with tactile but also fewer corrected
  errors
• Time to enter phrases
• Physical lt Tactile lt Softkeys

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Experiment 2 Tactile Version 2

• Added spatial awareness
• Increased accuracy
• Decreased KSPC
• Decreased Time to Enter

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T-Bars

• Uses a gradient of
• actuator intensities
• Feels like round pipe
• User is instinctively guided

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File-o-Feel and Touch n Twist

• Two fingers to scroll
• No T-Bar interaction
• One finger to select
• Feel along T-Bar
• Looks like captains wheel
• Use two fingers to turn
• Slide along spoke (T-Bar)
• to select

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References

• http//www.dcs.gla.ac.uk/stephen/
• http//code.google.com/p/iphone-haptics/