1. Automatic Weightlifting Spotter Final Presentation Senior Design I April 24, 2014

2. Team Members Chris Childers Electrical Engineering Nathan Carroll Electrical Engineering Garrett Doorenbos Electrical Engineering Team Leader Drew Bosarge Electrical Engineering

3. Faculty Advisor Dr. Robert Reese Professor ECE Department

4. Outline Problem Solution System Overview Constraints ❖ Technical ❖ Practical ●Progress ●Testing ●Future Goals ●Questions

5. Problem When lifting free-weights, a spotter must be present to ensure the safety of the lifter. When a spotter is unavailable, weightlifters are likely to lift without one, exposing themselves to injury and possibly death. From the years 1999-2003: o 1-4 deaths annually involved asphyxiation from neck compression o As many as 3,820 injuries per year may be related to bench press failures[1]

6. Solution A microcontroller-based system that will use sensors and a motor to allow users to lift weights safely without a spotter: The Automatic Weightlifting Spotter

7. System Overview

8. Constraints

9. Technical Constraints NameDescription Detection of BarThe device must detect the position, speed, and direction of the bar. Weight LimitsThe Automatic Weightlifting Spotter must be able to handle weights ranging from 45 pounds to 405 pounds. Reaction TimeThe product must have a reaction time that is fast enough to protect the user from falling weight.

10. Technical Constraints NameDescription NotificationsThe Automatic Weightlifting Spotter must implement a user interface to indicate the status of the machine to the user. Power RequirementsThe device must run on 120 VAC power.

11. Practical Constraints Health and Safety - Fail Safes Foot release pedal to lift all weight Safety bars to save user from falling weight Locking spool to prevent motor from dropping weight in a power outage

12. Practical Constraints Sustainability - Regular maintenance Frame Motor Tension Cable Pulleys Bar and Attachments

13. Prototype

15. Barbell Attachment

16. Prototype Pressure Sensor

17. Prototype Pulley System

18. Prototype Wheel Encoder

19. Prototype Motor

20. Prototype Motor Control

21. Prototype Breadboard

22. Prototype Arduino Mega 2560

23. Prototype User Interface

24. Testing

25. Weight Limit The recommended range of weights for the machine is 45-405 lbs. The machine successfully lifted 405 lbs, as seen below.

26. Wheel Encoder Fig. 1: Wheel Moving In Forward Direction Fig. 2: Wheel Moving In Backward Direction

27. LCD Display ●D11: Register Select ●D10: Enable bit ●D9-D6: Data Lines

28. Pressure Sensor The pressure sensor gives a resistance value that is dependent on the amount of pressure that is applied to it.

29. Foot Pedal Internal pullup resistors in Atmega chip are 20 kOhm

30. Future Options

31. Possible Modifications MP3 Capability Counterweight alternatives Capability to use for other lifts Alternatives for measuring position

32. References [ 1] V. Patteson Lombardi, “Petition Requesting Labeling of Weightlifting Bench-Press Benches to Reduce or Prevent Deaths Due to Asphyxia/Anoxia,” unpublished.

33. Automatic Weightlifting Spotter Final Presentation Senior Design I April 24, 2014