ECEN 4013 Project II Research

Locking Mechanism & Power Supply

Table of Power Requirements

Power Requirements3.3V: 5V: 12V 24V

X-Bee 50 mA RFID 30 mA Visual 120 mA Lock 25 mA

PIC 300 mA IR Emitter 50 mA

Audio 150 mA

Total 350 mA Total 230 mA Total 120 mA Total 25 mA

Total Current Used: 725 mA

Level 2 Block Diagram - Power

Level 2 Alt. Block Diagram - Power

Alt. Power Block Explained

• Larger Battery: Several aspects of this battery were very nice; it had a large capacity, large output current, and AC charging. I ultimately decided, though, that the change in cost ~$50 wasn’t worth the unneeded difference.

• Voltage Dividers: Using resistive voltage dividers to step down the voltage (5 to 3.3 and 27 to 24 & 12) dissipated power unnecessarily, even though it would have been simpler. Regulators do a better job of stepping down voltage.

• Using the step-up booster allowed us to run everything off of the single 5V supply, eliminating the need to use the 9V batteries. This also simplifies recharging and maintenance.

Level 2 Block Diagram - Lock

Level 2 Alt. Lock Block Diagram

Alt. Lock Block Explained

• I could have used a 1.5-3.0 V hobby motor instead of the maglock. The benefit would have been the lower voltage requirement, but I would have had to construct a locking mechanism from scratch for the gear on the motor to control. The code for implementing the motor-controlled lock would also have been far more complicated than simply turning a transistor on and off.

Lock Simulation On

Lock Simulation Off

Parts ListPart: Part #: Quantity:

Voltage Step-up (12 & 24 V)10 uH Inductor LQH31CN100K03L 245kOhm Resistor CMF6045K000BEBF 11M Ohm Resistor MF1/4DCT52R1004F 2Schottky Diode ZHCS500TA 24.7 uF REA4R7M1EBK-0511P 491k Ohm Resistor MF1/4DC9102F 1Voltage Booster ZXLD1615ET5TA 2

Power Regulation (3.3 & 5 V)3.3V Regulator LD1117S33TR 25V Regulator S-1165B50MC-N7J-TF 3

Locking Mechanism

Lock

http://www.amazon.com/Skylink-MC-201-Electro-Magnetic-Lock/dp/B000KL2M64/ref=sr_1_4?ie=UTF8&qid=1330628782&sr=8-4 1

Transistor 2PA1774Q,115 11k Resistors RN732BTTD1001F25 2

Power Supply

5.3V Battery Pack

http://www.amazon.com/PowerGen-External-Blackberry-Sensation-Thunderbolt/dp/B005VBNYDS/ref=sr_1_1?ie=UTF8&qid=1330633433&sr=8-1 1