Opti Cane Group 18 ECE 445 Spring 2019

Opti. Cane Group 18 ECE 445 Spring 2019 Angela Park Christian Reyes Yu Xiao Zhang

Introduction ● 36 million people are blind worldwide[1] ● Current solutions include: volunteer guides, service dogs, white canes ● White canes provide independence at relatively low costs

Objective ● Use sensor array for object detection in urban environments ● Create haptic feedback in the form of vibration patterns and differing intensity

Design

Physical Layout ● Sensors spaced 13 inches along the stick ● Stick must be held by user at 45° angle to align sensors parallel to ground

Physical Layout ● Robust design while maintaining lightweight factor ● Aluminum construction ● Rigid yet flexible to withstand tapping and bumping

Hardware Overview ● ● Power Supply- 9 V Li-Ion Battery Control Unit - Microcontroller Sensor Module Feedback Module

Block Diagram

Power Supply ● 9 V Li-Ion Battery housed in PCB housing ● Removable ● 5 V, 3. 3 V, and 2. 8 V voltage regulators

Total Current Draw Device Quantity Current Laser sensor (active ranging mode) 4 76 m. A Haptic Motor Driver (average battery current during operation) 1 2. 5 m. A Motor Disc (maximum rated current) 1 60 m. A Microcontroller (16 MHz at 5 V) 1 10 m. A Total 148. 5 m. A

Power Supply (Results) ● Starting voltage: 9. 69 V ● Ending voltage: 8. 57 V (after 3 hours)

Control Unit ● ATmega 328 p ● 16 MHz clock, 5 V operating voltage

Laser Sensor Module ● VL 53 L 0 X Time-of-Flight Laser Sensor ● Detection range: 30 mm - 2. 2 m

Laser Sensor Array (Results) - Plot

Laser Sensor Array (Results) Analysis ● Percent error calculation ● Average percent error ○ 2. 017%

Feedback Module ● DRV 2605 L motor driver ● Provides tactile information from sensor array

Haptic Feedback (Results)

Software Overview Sensor Number Starting from Bottom of Cane to Top Vibration Pattern 1 st sensor (bottom) A single vibration separated by a pause. 2 nd sensor Two vibrations in quick succession separated by a pause. 3 rd sensor Three vibrations in quick succession separated by a pause. 4 th sensor (top) Four vibrations in quick succession separated by a pause.

Software Flowchart

Future Hardware Development ● Incorporate battery gauge ● Battery rechargeability ● Gravity sensors, such as gyroscope or accelerometer, for orientation ● Molded handle for user to hold at correct orientation

Future Software Development ● Unique stairs discrimination ● Battery life monitor ● Variable detection range

Ethics and Safety ● Guide users around obstacles through a safe path ● Will not purposefully guide users through dangerous environments ● Will not fabricate false information ● Shall not be used as a weapon ● Violating will infringe upon IEEE code of ethics[2]

Conclusion ● Sensor detection range tested and verified ● Sensors successfully integrated with vibration motor feedback through I 2 C communication

Questions?

References [1] World Health Organization, ‘Blindness and vision impairment’, 2018. [Online]. Available: https: //www. who. int/news-room/factsheets/detail/blindness-and-visual-impairment. [Accessed: 3 -February-2019]. [2] Institute of Electrical and Electronics Engineers, Inc, “IEEE Code of Ethics”, 2006, Available: https: //www. ieee. org/about/corporate/governance/p 78. html