Open Sesame

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Open Sesame
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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

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Description

• Open Sesame is a portable, affordable, compact
  and easy-to-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.

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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
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Physical Device Design
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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.
• Analog power regulation could be done off the
  board to free up space
• Packages could be placed on the bottom of the
  plane.
• More than 4 planes could be used for routing.

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Top Level Block Diagram
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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

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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

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Gear Assembly
Specialized Bevel Gear

• Designed with screw-holes for mounting plate and
  slots for crank
• 5 to 1 Gear Ratio
• Using Inventor 2015, force simulations proved
  required torque wouldnt damage gears with iron
  material

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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
• Step Resolution 1.8 - 200 steps
• Quadrature encoder provides feedback on the
  position of the motor axle

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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

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Power Distribution
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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.

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Challenges Faced

• PCB Design Validation
• Grounding plane issue
• Respin process
• Mechanical limitations
• 3D printing flaws
• Bluetooth proximity
• Standardizing distance measurements using
  bluetoooth connectivity

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Future Improvements

• Camera/Video integration
• Ability to see whos knocking at the door
• GPS-based proximity detection
• Battery monitor
• Smaller size

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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!!!
• Seriously though

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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

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Thank You!

• Questions?
• Comments?
• Concerns?