Open Sesame
1
Open Sesame Team
• Grant Apodaca
• Team Leader and Bluetooth
• Richie Agpaoa
• eCompass and power design
• Evin Sellin
• USB and embedded design integration
• Eric Taba
• Motor control and mechanical components
• Jeff Bolin
• Mobile app, WiFi and web server
2
Description
Open Sesame is a portable, affordable, compact and easyto-use door security accessory, that can unlock your door
remotely through WiFi with an android or iOS app, or it can
unlock your door through a Bluetooth proximity detector
that discriminates between authorized users. It requires a
very simple, non-invasive installation, and it is powered
from a 9v battery.
3
Current Smart Lock Market
August Smart
Lock
Kwikset Kevo
Open Sesame
Bluetooth
Yes
Yes
Yes
WiFi
Separate
Device
No
Yes
Platform
All*
iOS only
All
Installation
Partial Lock
Replacement
Complete Lock
Replacement
Uses Existing
Hardware
Hands Free
iOS only
No
Yes
Fits all doors
No
Yes
Yes
4
Physical Device Design
5
6
PCB Layout - Size
● Our prototype is made larger than it
needs to be to ensure success in our
design.
● In a consumer design, the processor,
wifi, bluetooth, SD card modules could
be made smaller with different package
types, like BGA.
o Analog power regulation could be
done off the board to free up space
o Packages could be placed on the
bottom of the plane.
o More than 4 planes could be used
for routing.
7
Top Level Block Diagram
8
Bluetooth
● Part used: RN42XV
● Allows device to be activated in close quarters, regardless of internet
connectivity
● Device can be set such that it locks and unlocks automatically when
bluetooth presence is detected
● Supports secure simple pairing
● Low power sleep mode
9
Application
• Main user interface
• Includes controls, settings,
and automatic status
updates
• Multi platform
• Android, iOS, Windows
Smartphone, etc…
• Server communication
• Used for authentication
and broadcasting/ receiving
updates
10
Gear Assembly
Specialized Bevel Gear
● Designed with screwholes for mounting plate
and slots for crank
● 5 to 1 Gear Ratio
● Using Inventor 2015, force
simulations proved
required torque wouldn’t
damage gears with iron
material
11
Motor Control
●
Motor driven by dual H Bridge chip
●
Bipolar hybrid stepper motor operates bolt, locking and unlocking door
●
Full-Step Motion: lower power consumption
o
Step Resolution: 1.8° - 200 steps
●
Quadrature encoder provides feedback on the position of the motor axle
12
E-Compass
● Part used: LSM303D
● A digital 3-axis accelerometer and 3-axis magnetometer in
a single package.
● Used to determine if the door is open, closed, or ajar
● Calibrated such that the magnetic field generated by the
motor do not cause distorted measurements
13
Power Distribution
14
USB and Non-Volatile Memory
SD
● Originally SD card was to be used for
memory expansion
● Eventually was exchanged for USB
USB Flash
● Opens possibility for future integration
of peripherals such as cameras, or
other sensors.
15
Challenges Faced
● PCB Design Validation
o Grounding plane issue
o Respin process
● Mechanical limitations
o 3D printing flaws
● Bluetooth proximity
o Standardizing distance measurements using bluetoooth connectivity
16
Future Improvements
● Camera/Video integration
o
Ability to see who’s knocking at the door
● GPS-based proximity detection
● Battery monitor
● Smaller size
17
Sage Advice
●
●
●
●
●
●
Get started early!
Plan ahead, include redundant paths
Include as many test pins as possible
Pin out as many GPIOs as possible
Use debugging tools
Listen to Professor Johnson!!!
o
Seriously though
18
Special Thanks
●
●
●
●
●
●
●
●
●
John Johnson
Wei Dai
Ilan Ben-Yaacov and
Vincent Radzicki
NXP SemiConductors
SunStone Circuits
Rapid Prototypes
The ECE Shop
Department of
Mechanical Engineering
Aubrey Shanahan
19
Thank You!
Questions?
Comments?
Concerns?
20