This document summarizes the Sense-It project, which aims to help visually impaired individuals navigate campus spaces using Bluetooth beacons. The system uses compact RF devices placed near locations of interest that mobile devices can detect to provide navigation notifications. Testing showed the beacons could reliably connect within 200 feet and transmit through walls but not floors. Future work includes mapping locations using triangulation, integrating with Android, and making the devices smaller. The project was funded by Sonoma State University.

1. Sense-It
Juan Soto, Anthony Hargrove | Prof. Don Estreich | Rob Gee | Sonoma State University
Assistance from: Aaron Marquez, Nick Alvarez
Campus Navigation
Arriving at a new campus can be daunting. For
those who are visually impaired, it can be
nearly impossible to navigate without
assistance from others.
Solution
By placing compact RF devices near doorways or unique points of
interest, visitors can use their mobile devices to locate each iBeacon
to aid in their navigation.
Project Overview
Construction
PCB Fabrication
• Copper etching
process
• Surface mount
components applied
using a solder paste
over hot plate
• Terminals added by
hand using iron and
drill press
PIC Configuration
• Dual-UART model
chosen for flexibility
• Code written in
XC32 (C derivative)
• Extra I/O for future
peripherals
Bluetooth
Configuration
• Interfaced through
AT commands using
serial terminals
• Care must be taken
when considering
orientation and
grounding
Materials
Materials (detailed list) Quantity (be specific)
Bluetooth Module (HM-11) 2 per Wall Unit / 1 per Handheld
PIC32MX270F256b 1 per Unit
iOS Device 1 per User
Wall Mounts 1 per Location
Handheld Enclosure 1 per User
3.7V Battery 1 per Unit
Procedure
Download
campus info
from App
Store
Update
Select points
of interest
from pull down
Customize
When within
close
proximity of
location,
notification
occurs
Notify
Download any
available
location info
from beacon
Inquire
Data / Observations
• At 0dBm power, module pairs beyond 275 feet. Reducing power
output to -24dBm reduces range to approximately 200 feet.
• No null spaces discovered within 15 feet of beacon.
• Through floor signal reception is very low.
• Signal through doors and walls is strong but diffused.
• iOS response to Beacons is prompt and may be tuned to distances.
Typical RF Pattern
Conclusion
• Our measurements have shown that we can reliably notify our
users of relative proximity.
• Attenuation due to objects like bodies will likely hinder the
effectiveness for use as a navigation device.
Future Work
• Mapping through triangulation
• Android integration
• Professionally produced multilayer boards could permit much
smaller devices
• Upgrade to dual-mode Bluetooth modules
Thanks To
We would like to give thanks to Sonoma State for recognizing our
project and funding it through the SOURCE Awards program. Sonoma
State Engineering Department for their assistance throughout. Nick
Alvarez and the MESA program at SRJC. Special thanks to Prof. Don
Estreich for believing in our project and providing us with assistance
along the way.Numerous environments were chosen
to characterize the RF pattern
Electrical Engineering