Transcript Presentation

smart seating
Team 1
Srini Srikumar
Neel Mouleeswaran
Mitchell Appelbaum
Idea Introduction and Project Overview
The Idea
Smart Seating is a platform that
seamlessly connects people to
access-based facilities. The protocol
layer adds data-driven insights that
can be used to maximize resource
usage.
Project Breakdown
1.
1.
2.
3.
Portable & Flexible Package
 Can be placed in virtually any open
workspace
 ISO 14443A-compliant, can work with a
mix of cards and key fobs
Robust, Power-Efficient System
 Can be configured for long battery life
in facilities where power cords are not
always convenient
Security is Key
 Data obfuscation between device and
cloud services
 Primary authentication scheme with
tag UID (invariant)
Modular Breakdown
Flexible, Robust, and Secure
2.
3.
Sensor Bars + Microcontroller Solution
 Data Collection Unit
 MFRC 522 RFID Readers
 ATMega 328p Microcontroller (8-bit, 16 MHz)
 9V to 5V to 3.3V Power Conversion
schematic that is current limited and capable
of operation >6 hours
Data Processing Unit
 Data Processing Unit onboard ATMega 328p
microcontroller
 Features Round-robin algorithm to cycle
through different card readers
 Makes network request to server and returns
to rotating between readers
Data Transmission and Data Presentation
 W5100 Ethernet controller interfacing with
RF-45 Ethernet jack
 Heroku application server which produces
dynamic updates and analytics for both user
and manager
2
Smart Seating Value Proposition and Use Cases
Alignment with Design Decisions
Use Case Breakdown
Small-Size Classroom Check-In
 Ideal setup for a small classroom that has various chairs
and desks for students
 Can push content to only those students present
Laboratory Check-in and Updates
 Current lab attendance done manually and there is a lack
of updates on equipment and instructor feedback
 Instructor portal allows for content push and tracking of
where students are sitting for best support
Disaster Relief Checkpoints




Picked MFRC 522 for cost-friendliness and ability
for low-power operation that can run on minimal
amount of hardware
MiFare cards provide superior data protection with
UID HEX values hard-coded into the card making
it near impossible to clone
ATMega328p microcontroller allows for up to 5
SPI devices to run asynchronously while provide
memory capability to store and release
information dynamically
W5100 Ethernet controller easily interfaced with
ATMega and has capability to connect to external
servers while using minimal power
 Low-power solution in areas of potential danger that do
not have access to telecommunication
 Easily implementable on ID cards and users from across
the world can track safety and location of loved ones
Value Analysis
 Able to cater to the needs of both educational and
potentially government clients while still providing security
demanded by corporations
 Hardware is low-power yet robust enough to handle
multiple devices and push dynamic content within 10
seconds of card read
Figure 1. Interfacing diagram for Smart
Seating that displays modular design.
Smart Seating has a wide array of use cases beyond the educational setting - due to the flexibility of the
platform from a hardware-first standpoint, the system can be configured to tackle a number of large-scale
resource optimization and data collection problems today.
3
Design - Goals
hardware-first
modular
system
low-cost
scalable
Portable System
Power-Efficient
Open Platform
Design Strategy
Cost Effective
4
Design - Goals
Design Strategy
hardware-first
Small enough to
place on a desk in a
lab, classroom, or
workstation setting
•
Work anywhere that
has an Internet
connection
•
No plug needed
operate solely on
battery power
•
•
•
Enough power to last
through a lab
session, discussion
section, or exam – at
least 3 hours
Allow multiple
scanners per device
to maximize
efficiency
Develop algorithms
to sleep devices
when they are not in
use and avoid
power-hungry tasks
low-cost
scalable
Cost Effective
Power-Optimized
Portable System
•
modular system
•
•
•
HID units sell for
$100-300 and allow
one card to be
scanned at one time
Market research
shows an
opportunity for a
device to sell at
$50-100
Device should be
extensible to
support any feasible
configuration of card
readers
Open Platform
•
Instructor-facing
admin dashboard
•
Live student
monitoring &
contextual
notifications
•
Device management,
health & diagnostics
•
Flexible API for a
variety of check-in
strategies
5
Hardware Overview – Full System
Data Processing Unit
Data Collection Unit
RF Sensor Bar



Power Unit
Power supply
Data
9V battery + 5V
regulator to power
DCU, along with other
devices used to
regulate current
Datastore

Push Notifications
API
Single cloud-based dyno handling request logic
and push notifications. Persistent datastore
tracking students and contextual information for
each bench.
Power
requests.



Ethernet adapter
Microcontroller
Powers the logic behind the data collection
algorithms for sensor scheduling and network
Power Module
Request Module
PCB Module
Data
Sensor Module
Client Broadcast Unit
Power Module

Web portal
Provides administrative
functionality and
device monitoring to
instructors
6
Hardware Overview – Data Collection Unit
Hardware Components
MiFare RC522
- 13.56MHz
- 3.3V data line
-
ISO 14443A-compliant
Atmel ATmega328P
- 20MHz RISC
- 2KB SRAM
- 5V operation
WIZnet W5100
10/100 controller
Integrated MAC
16KB data buffer
3.3-5V operation
Electrical Components
-
Ethernet Adapter Schematic
16MHz oscillator
25MHz oscillator
1-10K resistors
1 μF capacitors
Green LEDs
7
Hardware Overview – Data Collection Unit
Hardware Components
Sensor Module Schematic
MiFare RC522
- 13.56MHz
- 3.3V data line
-
ISO 14443A-compliant
Electrical Components
-
Ethernet Adapter Schematic
16MHz oscillator
25MHz oscillator
1-10K resistors
1 μF capacitors
Green LEDs
8
Hardware Overview – Data Collection Unit
Hardware Components
PCB Schematic
Atmel ATmega328P
- 20MHz RISC
- 2KB SRAM
- 5V operation
Electrical Components
-
16MHz oscillator
25MHz oscillator
1-10K resistors
1 μF capacitors
Green LEDs
9
Hardware Overview – Data Collection Unit
Hardware Components
Ethernet Adapter Schematic
WIZnet W5100
10/100 controller
Integrated MAC
16KB data buffer
3.3-5V operation
Electrical Components
-
Ethernet Adapter Schematic
16MHz oscillator
25MHz oscillator
1-10K resistors
1 μF capacitors
Green LEDs
10
Hardware Overview – Data Collection Unit
Hardware Components
Request Module Tolerance
Bits (Card Dependent
RFID 3 different data stream
lengths (bits)
2048
Card Reader Read Speed
(bits/second)
WIZnet W5100
10/100 controller
Integrated MAC
16KB data buffer
3.3-5V operation
Electrical Components
-
16MHz oscillator
25MHz oscillator
1-10K resistors
1 μF capacitors
Green LEDs
16000
32000
424000
424000
424000
0.00000002 0.00000002 0.00000002
6
6
6
Digital MUX Delay
Arduino GPIO Read Speed Delay
Arduino Serial Write Speed
(bits/s)
0.002
0.002
0.002
9600
9600
9600
Transfer Rate to W5100 (bits/s)
9600
9600
9600
Adapter
Schematic
0.43349688
3.37306920
6.74413839
1
Ethernet
Total Time from Read
to
Process (seconds)
1
8
11
Software Overview – Data Processing Unit
Technologies Used
Webserver Integration Tests
Heroku Cloud Application Platform
- Single dyno, 512MB RAM
- Postgres SQL database service
Flask Webserver
- Python microframework
- Support for unit testing
- RESTful request support
- Headless client support
- Email integration with flask-mail
Request Module Workflow
12
Hardware Overview – Power Unit
Components Used
-
5 V Power Circuit Schematic
LM7805 5V linear regulator
9V DC Battery
LED diode indicator
1uF capacitor
10k pull-down resistor
LD1117 3.3V linear
regulator(same circuit
structure)
Software Overview – Client Broadcast Unit
Technologies Used
-
Instructor Web Portal
Python-Flask
Javascript
13
Design - Results
PowerOptimized
Portable System
•
Assembled unit in
enclosure is roughly
8 x 6 x 3 in.
•
Works anywhere that
has an Internet
connection
•
No plug needed, can
operate solely on
battery power
Design Strategy
Cost Effective
•
9V battery + 5V
regulator
•
Independent power
units for RFID,
Ethernet, and
microcontroller
•
3.3V data lines
 6-hour
battery life
 hardware-first
•
$65 to make the
barebones unit, 1 RF
reader installed
•
•
•
$70 / 2 readers
$80 / 4 readers
$100 / 8 readers
•
Less portable HID
units sell for $100300 and have less
features & reduced
security
 modular system
Open Platform
•
Instructor-facing
admin dashboard
•
Live student
monitoring &
contextual
notifications
•
Device management,
health & diagnostics
•
Flexible API for a
variety of check-in
strategies
 low-cost  scalable
14
Testing and Verification Plan
PCB
• Check power on
PCB
• Ensure outputs
from
microcontroller
• Ensure outputs
from Ethernet
module
Microcontroller
• Capture
waveforms
from MISO
and MOSI
• Capture
waveforms
from SDA and
SCK
Miscellaneous
• LED used to test
successful card
read
• Ensure card
reads in cycle
for multiple
cards scanned at
the same time
System Overview: Data Collection Unit
Hardware Communication Process
SPI Communication
MFRC 522 MiFare RFID
Reader
ATMega 328p Micocontroller
Implementation
W5100 Ethernet Controller
Figure 2. This is a
sample of our SDA line
which shows operation
in the SPI_0 mode. The
spike that is seen when
the signal go low
indicates that reader
being selected
Figure 3. This figure to
the left describe the
SPI_0 operation mode.
In this operation mode
the new signal will be
passed on the falling
edge of the clock and
will be updated on the
negative polarity.
1. Utilize the ATMega 328P as the SPI Master which will dictate which
Slave is active (active low) and will also determine clocking of each
device
2. Each RC522 is an SPI slave and the round-robin algorithm will provide
the correct SPI SDA data line (chip-select) value by setting every nonactive card reader to a high and setting the active one to low
3. To ensure proper network connectivity, once a card is scanned the SPI
SDA value (chip select) of the Ethernet controller will go low activating
this module while also setting each RFID to high until the network
request is successful
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Requirements and Verifications : Data Collection Unit
Sensor Bar Requirements




MISO Verification
Individual Sensor is able to be powered on and
able to output on data lines
Data lines are bi-directionally stepped down to
3.3V for communication between ATMega and
RFID
Sensor bar is able to sense standard HID card
Information from sensor is passed to
ATMega328p on PCB Module
We verified communication was working by probing
the Master in Slave Out pin on the RFID reader to see
that it was going high when a card was scanned. The
spike indicates a data transfer occurred.
General Verification
 Once powered the RFID reader light should turn
on bright
 When there was not enough power the light would
be dimmer indicating the reader was not
functioning properly
 Used LED diode to probe each pin on RFID and
set pins to high to check if out of the box unit
worked according to specifications
Figure 1. Circuit design of bidirectional
converter step down to 3.3V
Requirements and Verification: Power Unit
Power Unit Requirements



Take 9V battery and step down to 5V for usage
with the ATMega 328p and Ethernet module
Step down 9V input to 3.3V for RFID readers
Bidirectionally step down data lines from
ATMega to RFID readers
General Verification
 Probed each output of the LM7805 and the
LD1117 regulator to check for true voltage stepdown
 Ensured current was usable for components by
comparing output current to operating region of
each component
 LED verification for data line 3.3V step-down.
Each time the LED lit up indicated data transfer
was successful
 Achieved +/- .3V tolerance for each required
output
Linear Regulator vs.
Buck Converter
 Most common DC voltage step-down is linear
regulator but Buck Converter is industry standard
 Used linear regulators as opposed to Buck
Converter since our power requirements were not
high enough to justify Buck Converter
Figure 3. Datasheet detailing LM7805 5V
voltage regulator
 Buck Converter circuitry would increase bulkiness
and would require additional product maintenance
 Buck Converter uses inductor to produce
opposing voltage to reduce output voltage and
energy that is stored via magnetic field allows for
current amplification
Successes and Challenges
Challenges
Successes
•
•
Smart Seating
works in full on
non-private
networks
Received
access to the
university
network via
Ethernet
shields
•
Accessing our
server on Heroku
on the university
network
•
Soldering on the
W5100 (each pin
is 0.16mm x
0.32mm)
Reasoning
• Heroku is not
certified by
University of Illinois
• During the process we
soldered pins
together and
grounded many
transmission lines,
causing
microcontroller to
send incorrect data
Verification Successes
Successful Verifications
•
Detect card within 1.8 inches
•
Cycle through RFID Scanners and translate card data into student
identifier
•
Establish Master-Slave relationship with microcontroller and Ethernet
shield
•
All modules are powered
Unsuccessful Verifications
•
Microcontroller on PCB
•
While reconstructing the Ethernet module on the PCB, some of
the microcontroller output pins were grounded, causing
incorrect data being sent to the server via the Ethernet shield
PCB Schematic
PCB Design
First PCB Design
•
First board to contain all elements on one board to save space
Errors in First PCB Design
Used the 80-pin LQFP reference package → W5100 datasheet
W5100 is much smaller and would not fit the first design
•
•
Second PCB Design
Changed the dimensions of the W5100
ATMEGA328P to be through-hole to make soldering easier
•
•
Post Second PCB Design
•
•
Could use software to recreate the multiplexer
Separate the PCB into different modules (Ethernet, microcontroller)
• Reduce manual errors (soldering)
• Make the board more portable.
Wrap Up and Future Ventures
Cost Effective
Open Platform
Portable System
•
•
•
Power-Efficient
Long-term
initiatives
Short-term strategy
Create modular PCB
design for each
component
Improve power
efficiency by
replacing linear
regulator and using
higher mAh battery
Design more userfriendly CBU to
provide additional
functionality
•
•
•
Establish connection
with University of
Illinois to start alpha
testing of product in
select classes
Further
standardization of
card-read stations
and functionality
create relationships
with non-profits for
distribution in
certain cities for in
times of need usage
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