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Haptic Lock

By Oliver Schneider and Anna Macaranas.

Realized during the Sketching Haptics Workshop @ UBC during August 2011.

A handheld security lock that uses haptic feedback as its passcode.



Our final project is a handheld device simulating the properties of a combination lock. Three red LED lights symbolize a sequence of three sensations needed to unlock the device. When the user begins to move the analog stick, different sensations are felt depending on the direction of motion. When the user wants to 'key in' a particular sensation into the lock sequence, they simply press down the analog stick.


We were inspired by Bianchi et al.'s work at CHI 2011 [1]. We were also interested in learning how to use haptuators and analog sticks.

Benefits of Design Intervention

  • Haptuator embedded within device to give distinct but silent feedback. This limits output to the person touching the device.
  • Analog stick placed on top of haptuator. This allows immediate feedback from user action. It also allows our device to be uni-manual.
  • LED lights provide feedback of lock's state. It guides the user through entering a lock sequence and let's the user know if the device is locked or unlocked.
  • After each entry into the sequence, the control mappings randomize to avoid observers from memorizing the sequence of your movements.


  • Some sensations felt too similar to each other. In particular, the slow pulse and heartbeat seemed identical at first use.
  • The haptuator needed to be connected to amplifier to control the intensity of the feedback. This limited mobility.
  • The LED lights did not provide feedback on correct or incorrect entries during sequence entry. This could be seen as a security benefit but usability faux-pas.

Use Case

Pick up device. Three red LEDs symbolize a locked devicehl_usecase1.jpgBegin moving analog stick. Enter first key in lock sequence.hl_usecase2.jpgPress analog stick inwards. Move to second key in sequence.
Press analog stick inwards. Move to last key in sequence.hl_usecase0.jpgCase 1: Code is incorrect. Device restarts to default state.hl_usecase3.jpgCase 2: Code is correct. Device is unlocked.

Similar Work

Bianchi et al. demoed a analog dial that gave different haptic sensations. The purpose of haptic feedback is to prevent others from “looking over the shoulder” and finding out your PIN.


We had difficulty encasing the haptuator in material that is sturdy but thin enough to let the haptic feedback go through. We had issues getting the timing of the LEDs right in code due to the nature of Arduino functions.

Future Work

Future models would use gestures rather than an analog stick. LED lights would be embedded on the device, as opposed to being attached to a breadboard.



  1. Bianchi, A., Oakley, I., Kostakos, V., and Kwon, D-S. The phone lock: audio and haptic shoulder-surfing resistant PIN entry methods for mobile devices. In Proc. TEI 2011, ACM Press (2011), 197-200.
courses/2011.ubc.anna_oliver.txt · Last modified: 2011/09/03 08:12 by