|42||Vehicle Detection Cane
|Neva Manalil (manalil2), Nick Halteman (nth2), Aditi Panwar (apanwa3)
Blind people who use a cane rely on their hearing to determine if it is safe to cross a street. Gas fueled vehicles make a loud noise when driving by, but electric vehicles are virtually silent. With electric vehicles becoming more common it becomes more difficult for blind people to navigate as they cannot easily determine if it is safe to walk.
# Solution Overview
Our solution for determining if an area is safe to walk is a battery-powered cane attachment. When activated by pressing a button, it uses a radar sensor to determine if there are cars or other fast moving vehicles in front of the user and alerts the user with vibration if it is not safe to walk.
# Solution Components
## Sensor Subsystem
The sensor subsystem is responsible for using the doppler effect to identify moving vehicles. This technology has been in development in recent years for use in fully and partially autonomous cars. By emitting high frequency microwave “chirps” (above 77GHz) and “listening” for reflections off of objects, their general location and speed (the doppler effect) can be determined. Further processing can be performed to get more data on the object such as size and certain material characteristics (useful for differentiating between cars and other moving objects like people). We plan to use a radar transceiver such as the TEF810X (linked below), that has been designed for automotive use, and thus has no problem detecting cars at typical driving distances.
An accompanying radar microcontroller is necessary to control and process data from the radar transceiver. It supports a hardware interface with the radar transceiver and hardware acceleration of common radar signal processing tasks. We intend to, as with the transceiver, use a radar microcontroller designed for automotive use such as the S32R Radar Microcontroller (linked below). This microcontroller is actually designed for use with the TEF810X.
## User Interface Subsystem
The radar microcontroller lacks the ability to interface with motors, speakers, and buttons, so a secondary microcontroller will be responsible handling them. The two microcontrollers can communicate through I2C or a similar interface. This allows us to be flexible with where some of the processing is done, as only the DSP intensive tasks have to be completed on the radar microcontroller. The following devices will be controlled by the secondary microcontroller:
Rocker Switch (with raised mark on one side) - turns the device on and off
Push Button - enables car scanning when held down
Vibration Motor - Relays information to the user through various patterns of vibration. This can include the presence of cars, mode of operation, etc.
Piezoelectric Speaker - To make a sound when the battery is about to die
## Power Subsystem
The system will run off two 18650 cells. A usb charger pcb (board used for making portable phone chargers, example linked below) will allow the cells to be charged with a usb cable . The board will also supply 5v at set currents. Voltage regulators will be used to correct the voltage for individual components (likely just one for 3.3v). A voltmeter will be used to determine the voltage across the battery and if the voltage becomes low, the piezoelectric speaker will alert the user.
18650 Cells - provides power for the system
USB Charger PCB - handles recharging the batteries and provides 5v
Mini Voltmeter - To keep check on the charge in the battery (may be included in secondary microcontroller)
# Criterion for Success
The device reliably detects moving cars and alerts the user.
The device is easily operated by a blind person.
The device is comfortable and doesn’t infringe upon regular use of the cane.
The device is safe to rely on.