8. Wheel Encoder
● For small vehicles
● Quite cheap
● Error occurs due to slippery wheels.
● Error increases over time.
● No error correction method.
9. Attenuation of RF Signals
● Bluetooth RSSI.
● Wi-Fi.
● Cell Tower.
● RFID.
10. Wi-Fi positioning system
The most common and widespread localization technique used for positioning with
wireless access points is based on measuring the intensity of the received signal
Problems : Low accuracy
11. Flickering Light Patterns
● A unique ID is transmitted over light bulbs with modulated flicker.
● Phone camera can sense variations in light intensity and demodulate the
signal to determine it’s current location.
● Requires a line of sight.
● The determined location is within a large diameter, as long as the camera can
see the flicker.
● Can determine your location within a the building. It can tell you which room
you’re in, but not exactly your location in the room.
12. Ultrasonic Beacons
● Speakers are placed in known places in the room and emitting ultrasonic
pulses.
● The phone can detect the waves, and the time between receiving the signal
from each speaker, and determine its location with small error.
● Can determine location in 3D. However, orientation can not be known.
● Doesn’t need LOS.
● Needs an accurate synchronization between sent signals.
13. Our new approach
● Cheap
● Insanely Fast
● Easy to setup
● Very accurate
● Location + Orientation
15. Process of the project :
Divide the projects into small tasks
● Determine Hardware components.
● Test each component separately.
● Methods for interfacing with vehicle, web server ,android application and c#
interface
● Main function
● Map update, D* Lite algorithm
● Integration of all parts of the project.
● Documentation
● Presentation.
16. Full project overview
● Car get information about its location and orientation by scanning images
(special marks) on the ceiling.
● Processes this mark to get its location and orientation
● Raspberry Pi is accessed via a web server installed
● The server can control motors directly
● The Pi that can be accessed from any device on the network
● Manual control through server
19. Raspberry Pi 2 Model B
Specs
● A 900MHz quad-core ARM Cortex-A7 CPU
● 1GB RAM
● 4 USB ports
● 40 GPIO pins
● Full HDMI port
● Ethernet port
● Combined 3.5mm audio jack and composite
video
● Camera interface (CSI)
● Display interface (DSI)
● Micro SD card slot
● VideoCore IV 3D graphics core
22. H-Bridge L298 Module
Specs
● Dual full-bridge driver.
● Up to 36V operating motor supply voltage
● Up to 4A total DC current.
● 2A fuse for overcurrent.
● Over Temperature protection.
● Red LED indicator for motor supply and
Green LED indicator for control supply
44. D* Lite
In practise, works with real valued costs, rather than binary costs
g: estimate of the objective function value
rhs: one-step lookahead estimate of the objective function value
74. API - Features
● Server is on the Raspberry Pi.
● Can be accessed from any device on the network using the IP Address of the
Raspberry Pi.
● There’s a page in the server responsible for receiving the commands and
taking actions.
75. API - Features - Cont
● The URL takes the form of
http://raspberrypi/command.php?mode=func&func_name=car_forward
● The PHP checks if the variable Exists first using
● The php page gets the commands using $_GET[‘var_name’] , and calls the
corresponding function
78. ● The functions are defined in another PHP file
● The functions that control the Motors use other functions that execute
command line that control the H/W directly
● The command line utility is called GPIO Utility, part of the library WiringPi
API - Features - Cont
79. ● The command line utility is as simple as the following
Setup: gpio mode <pin> in/out/pwm/clock/up/down/tri
gpio mode 6 out
Write (Digital) gpio write <pin> 0/1
gpio wire 6 1
Write PWM gpio pwm <pin> <value>
gpio pwm 12 500
API - Features - Cont
94. Results
Applications:
● Increasing GPS Accuracy.
● Localizing a smart phone inside a museum
● Making a lot of house robots more realizable and better-operating
Problems:
● LOS between the camera and the flat surface.
