Trey Herrington Electrical Engineer - Backup Power Supply - Backup Power Supply - PCB Design - PCB Design Samantha Prine Electrical Engineer -Enclosure Design -Enclosure Design -Hardware Research -Hardware Research Jacob Ferguson Electrical Engineer Electrical Engineer -Backup Power Supply -Backup Power Supply -PCB Design -PCB Design Grant Richards Computer Engineer Computer Engineer -Packaging -Packaging -Hardware Research -Hardware Research Dr. Raymond Winton (Faculty Advisor) Daniel Sowards ( Team Leader ) -Electrical Engineer -Electrical Engineer -Power Supply Design -Power Supply Design

-Problem -Solution -Constraints -System Overview -Design Concept -Hardware -Packaging -Cost Analysis -Q&A

-Smart locks and security systems are excellent examples of how technology gives homeowners the ability to monitor the access and safety of their home. -The features of these locks and systems are innovative and easily integrated together, but this hasn’t been done, yet the cost for each separately remain high. [1] [2]

-Smart Lock Security (SLS), LLC has developed a product that successfully combines all the useful features of a smart lock with protection of a security system. -The SLS system is offered at a competitive price with uninterrupted service and the ability to personally monitor your home.

-On-site keypad access -Remote access via text message -Forced entry attempt notification -Inside panel for system modifications -Rechargeable backup battery in case of power outage

The system is wired directly into the customer’s electrical system and is therefore as reliable as the power supply. In case of power outage, the system can be powered from the backup power supply. [3]

The system will notify the homeowner via SMS if a forced entry is attempted. The user will also be notified whenever the door is unlocked with the external keypad or SMS. [4]

Arduino With GSM SHield Power Supply Keypads Lock LCD Screen Magnetic Switch

The relay for our design is a G5SB-14. This allows the back-up battery to power the system when the main power supply is down. There is a 5ms delay when it switches over to the battery but no delay when it switches back to the main supply.

The recharge circuit uses a DC-DC converter to take 12VDC from the main power supply and convert it to 24VDC. This setup is a dual level float charger for a lead-acid battery.

To the left is the actual wired circuit. It utilized a UC2906N made by Texas Instruments to charge the battery. It’s also comprised of an IE1224S DC- DC converter from XP Power. The bottom left picture shows the input power and the below picture shows the output voltage to charge the battery.

The battery life calculated is based off of the lock being activated 4 times per hour (2 entrances, 2 exits) and open for 1 minute each time Hours

To the left shows the schematic for the solenoid.

The wired side of the magnetic switch will be attached to the door frame and tied into the PCB within the wall. The non- wired side of the switch will be attached at the same location respectively on the door. Unlike the average door lock, the solenoid will be installed within the door frame allowing it to be easily wired to PCB. The door will be retrofitted appropriately to accept the solenoid while engaged. [9]

The backup battery and the power supply will also be installed inside the homeowner’s wall near the other system components. Wall spacing is ~4in Stud spacing is ~16in [7]

The outdoor panel will house the external keypad. Keypad dimensions: (2in x 2.7in) Overall dimensions: (3.5in x 5in) [5]

The indoor user interface panel will house the internal keypad and an LCD screen that will display system information and a menu with options to change system parameters. [5] Keypad dimensions: (2in x 2.7in) LCD dimensions: (3.75in x 1.5in) Overall dimensions: (5.5in x 7.5in) [6]

The PCB with components, the Arduino, and the GSM shield with all connecting wires will be packaged together in a plastic enclosure and installed inside the homeowner’s wall near the other system components. Wall spacing is ~4in Stud spacing is ~16in [8]

Main Components Cost Arduino $29.99 GSM Shield $99.95 Solenoid $9.95 Magnetic Switch $2.86 Power Supply $19.35 Battery $24.19 Lead-Acid Battery Charger $6.93 TOTAL $193.22

JanuaryFebruaryMarchApril Back-Up Power System PCB Design Packaging PCB Assembly Final Packaging Tests

[1] (2013, September 30). “August” [Online] Available: [2] (2013, September 30). “Goji” [Online] Available: [3] (2013, September 30). “Tax Breaks for Burglaries” [Online] Available: [4] (2013, November 20). “How to Pick a Lock on the Bathroom Door” [Online] Available: [5] (2014, March 2). “ Grayhill Standard Keypads” [Online] Available: [6] (2014, March 2). “ADH Technology Co. Ltd.” [Online] Available: [7] (2014, March 2). “VRLA Rechargeable Battery.” [Online] Available: [8] (2014, March 2). “Arduino.” [Online] Available: [9] (2014, March 2). “Hamlin.” [Online] Available: