AllanHuidobro

app-A

This project was made with MOMO, my senior design team.

app-A is an Android based application designed to assist visually impaired navigate the campus. It features all notable locations on campus and navigates people to those locations via GPS. Considering GPS can be rather inaccurate, beacons are deployed at entrances of buildings to help notify users when they have arrived at a location. In addition, there is an ultransonic sensor attachmed to a blind cane to further assist with more "local" obstacles. People and objects that a blind cane wouldn't come in contact with for example.

app-A Home Screen

I mainly handled all hardware related aspects on this project; circuit board, 3D-printed case and cane mount, programming, and communication.

The board is powered by an ATTINY84A-PU. An HC-SR04 ultransonic sensor is used to detect distance in front of the cane itself. An HC-05 is used to establish bluetooth communication with the application and relay ultrasonic sensor data to it. A cute little toggle button is used to cut power from the 9V battery to the board.

app-Arduino Schematic

There were additional components that went unused, a BNO055 motion sensor, and two hatpic motors. An issue with these components was that the addition of their libraries would cause an overflow in the attiny's memory u_u

app-Arduino PCB

The circuit board was programmed using the Arduino IDE, and an Arduino Mega interfaced to the ATTINY via the Mega's ICSP Header pins.

The case itself was modeled in Blender(yikes). It is designed to easily slide onto the cane and tightened in place via a small screw. The case has 3 parts, the bottom piece, where the pcb sits on, the top lid, that encases everything, holds the battery and a slot in the rear to attach to the cane, and a battery lid. Going back, I would probably opt to use SolidWorks, as Blender is definitely not well suited to build functional parts.

app-Arduino Case

Future improvements for this project:

  • A chip with more memory capabilities than the ATTINY84A-PU in order to be able to use extra components like the haptic motors and motion sensor
  • SMD components instead of through hole to decrease the circuit board's footprint
  • Standalone; operates without the need for the app-A application
  • Additional distance sensors like an IR distance sensor to make up for the shortcomings of the Ultrasonic Sensor