Automatic Weightlifting Spotter Midsemester Presentation Senior Design II October 7, 2014

Team Members Chris Childers Electrical Engineering Software/PCB Design Nathan Carroll Electrical Engineering Hardware/Packaging Garrett Doorenbos Electrical Engineering Team Leader Software/PCB Design Drew Bosarge Electrical Engineering Hardware/Packaging

Faculty Advisor Dr. Robert Reese Professor ECE Department

Outline ●Problem ●Solution ●System Overview ●Constraints ○Technical ○Practical ●Hardware ●Testing ●Future Work ●Questions

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 : 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]

Solution A microcontroller- based system that uses sensors and a motor to allow users to lift weights safely without a spotter:

System Overview

Constraints

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.

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.

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

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

Hardware

Progress - Counter Weight

Progress - Main PCB Schematic

Progress - Main PCB Layout

Progress - User Interface Schematic

Progress - User Interface Layout

Testing Procedure ●Ensure that new counterweight placement does not interfere with lifter ●Test PCBs for correct routing ●Test software to ensure that it works correctly with new hardware ●Make sure that stall detection and foot pedal detection are working

Potential Problems ●Layout/Routing errors ●Unforeseen problem with pulley system due to counterweight change ●Problems refactoring software for new hardware

Future Work ●Find or build an enclosure for PCB’s (3D printing is an option) ●Finalize PCB’s and have them sent off for fabrication ●Assemble PCB’s ●Test PCB’s for correct functionality ●Test software interaction with new hardware and make tweaks / improvements as necessary

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“Petition Requesting Labeling of Weightlifting Bench-Press Benches to Reduce or Prevent Deaths Due to Asphyxia/Anoxia,” unpublished.

Automatic Weightlifting Spotter Midsemester Presentation Senior Design II October 7, 2014