Object Detection for the Visually Impaired Justin Rice Christopher Zeh Zac Bond Casey Morford

Motivation Enhance the lives of the visually impaired through the creation of a wearable toolEnhance the lives of the visually impaired through the creation of a wearable tool –Locate near and distant obstacles –Detect nearby people –Create inconspicuous system –Eliminate the need for a cane

Design Decisions Ultrasonic transducers to locate objectsUltrasonic transducers to locate objects Pyroelectric sensors to detect peoplePyroelectric sensors to detect people Tactile output using vibrational motorsTactile output using vibrational motors Microcontrollers for processing the inputs and regulating the outputMicrocontrollers for processing the inputs and regulating the output

Design Decisions Criteria for choosing sensorsCriteria for choosing sensors –Range of detection –Angle of coverage –Cost Criteria for choosing microcontrollerCriteria for choosing microcontroller –Input and output capability –Cost and availability

Ultrasonic Sensors Previous work (Bomber Belt)Previous work (Bomber Belt) –15 ultrasonic transducers on belt –Sampled sequentially clockwise –Communicates serially with PIC that determines time of flight

Ultrasonic Sensors Modification to Bomber Belt systemModification to Bomber Belt system –PIC polls only the five front sensors ten timers per second –PIC computes a distance estimate for objects to the left, right, and middle –Uses predefined thresholds to indicate the relative closeness of objects detected

Pyroelectric Sensors RE200B Infrared detectorRE200B Infrared detector –Differential pair of sensors to cancel out background heat sources –Tuned to 8-14 µm for human detection –Needs amplifier to boost 20mVpp output –Unreliable, but manageable, output

Tactile Display Yokyo Parts FM31EYokyo Parts FM31E –3 small vibrating motors (1/2 inch diameter) –4500 3V input –Requires driver circuit to supply enough current

Tactile Display 3 output motors: left, right, and center3 output motors: left, right, and center 5 vibration intensities5 vibration intensities –Fully off for no objects or people –3 distance based levels –Extra pulses for human detection Attached to Bomber Belt in final systemAttached to Bomber Belt in final system

Microprocessors PIC18F242PIC18F242 –Time of flight computation for ultrasound –Communicates sensor readings serially HC11 with Fox11 Development BoardHC11 with Fox11 Development Board –Reads in serial output from PIC –Reads in pyroelectric data on input channel –Sends control signals to motor driver circuit

Ugly Prototype DemonstrationDemonstration –Ultrasonic transducers from the Bomber Belt perform range finding –Pyroelectric sensors detect moving people –Motors vibrate according to distance –All subsystems reside on different boards –Wear the belt at your own risk (~400 V pulses)

Future Work PIC and HC11 programs merged onto one devicePIC and HC11 programs merged onto one device Replace our 3 power supplies and 2 batteries with a single battery packReplace our 3 power supplies and 2 batteries with a single battery pack Sleeker, more stylish designSleeker, more stylish design –Everything on one board –Make it pretty

Questions?