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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 MarketAugust 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.

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.

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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 wouldn’t 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

o 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

o Grounding plane issue

o Respin process

● Mechanical limitations

o 3D printing flaws

● Bluetooth proximity

o Standardizing distance measurements using bluetoooth connectivity

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Future Improvements

● Camera/Video integrationo Ability to see who’s 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!!!

o 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?