Safety Motion Detector Final Presentation Senior Design I December 1, 2011

Safety Motion Detector Team Alden Stennis Jason Smith Programming Sensors Geoff Jakins PCB Design Website PCB Design Sensors Dr. Donohoe Faculty Advisor Electrical Engineer Programming Sensors Electrical Engineer Justin Parker Electrical Engineer

Outline Problem Solution System Overview Constraints Technical Practical Evaluation Senior Design II References

Problem and Solution

Problem Utility workers alone are in the field getting injured and are unable to receive help within a reasonable amount of time. There are approximately 600 deaths yearly from falling accidents in the work field.

Solution Safety Motion Detector – Wrist device monitors user’s movement – Signals the base station when no movement is detected

System Overview (Wrist Device) Motion Sensor Power Supply Transceiver MicrocontrollerInterface

Technical and Practical Constraints

Technical Constraints ConstraintDescription NotificationsVisual displays must indicate the safety status based on the user’s movement. Transmission DistanceThe base station must communicate data with the detection unit up to 200 feet. Battery LifeThe batteries must last for at least 24 hours. Temperature RangeThe SMD must withstand temperatures in the range of -40° to 185° F. Motion Detector Sensitivity Minimal motion, acceleration between -1.5 and +1.5 g 0 with minimum increments of 0.1 g 0. must be detected along one or more axes.

Practical Constraints TypeNameDescription ManufacturabilitySize The dimensions must be no larger than 3” wide, 3”long and 1.5” high SustainabilityRuggedness The wearable device must be capable of withstanding everyday use in the field.

Manufacturability Device must be small in size – Device will be no larger than 3” wide, 3” long, and 1.5” high – Must be wrist wearable to increase efficiency – Must not interfere with the user’s work

Sustainability Must withstand everyday use in the field – Water resistant – Function properly in hot or cold weather conditions Device encasement durability – Strong enough to handle accidental impact

Evaluation

Wrist Device

Microcontroller

Wrist Device Accelerometer

Wrist Device Notifications

Wrist Device Transceiver

Base Station

Transceiver

Base Station Microcontroller

Base Station Notifications

Acceleration Wrist Device: Standstill While the wrist device is at a standstill, the voltage output of each axis remains constant. The voltage of the z-axis is higher because of gravity pushing down on the top of the accelerometer.

Acceleration Wrist Device: Free Fall The highlighted values represent the wrist device in freefall. The Z-axis voltages were graphically plotted to show constant acceleration.

Range Testing A range test was done by separating the wrist device from the base station in 50 ft increments to check for proper functionality. Once the constraint of 200 ft was met, additional tests were done in increments of 10 ft to measure the maximum range.

Out of Range Test If the user is out of range, the notification lights will blink repeatedly. This will continue until the devices are back in range to communicate with each other.

Battery Life Current Draw - Microcontroller Awake Current: mASleep Current: mA

Battery Life Current Draw - Transceiver Awake Current: mASleep Current: mA

Battery Life Current Draw – Accelerometer Sleep and Awake Current: mA

Battery Life Current Draw – Total Circuit Awake Current: mASleep Current: mA

Actual Battery Life DeviceAwake Current (mA)Sleep Current (mA) Microcontroller Accelerometer 0.268N/A Transceiver Total Time Asleep(s) Time Awake(s) Sleep/Wake Cycle(s) Average Current(mA) Battery Life(hours) Battery Life(days)

Senior Design II Goals

Improve Battery Life PCB Design Build Enclosure and Package Improve Software Test Final Design

Timeline for Senior Design I AugustSeptemberOctoberNovember Research Ordering Parts Design Programming And Construction Prototype

Timeline for Senior Design II JanuaryFebruaryMarchApril PCB Design Software Refinement PCB Populating Testing Enclosure

References [1] "Census of Fatal Occupational Injuries (CFOI) - Current and Revised Data." U.S. Bureau of Labor Statistics. Web. 07 Sept [2] “Pic24FJ64GA102” [3] ”Pic24HJ32GP202” [4] ”AD22285-R2” [5] “MMA7660FCT” [6] “ADXL335” [7] “How does ZigBee compare with other wireless standards?” [8] “Xbee, Xbee Pro, Xbee Pro XSC” Page 5

Safety Motion Detector Final Presentation Senior Design I December 1, 2011