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

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

Faculty Advisor Dr. Robert Reese Professor ECE Department

Outline Problem Solution System Overview Constraints ❖ Technical ❖ Practical ●Progress ●Testing ●Future Goals ●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 will use sensors and a motor to allow users to lift weights safely without a spotter: The Automatic Weightlifting 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

Prototype

Barbell Attachment

Prototype Pressure Sensor

Prototype Pulley System

Prototype Wheel Encoder

Prototype Motor

Prototype Motor Control

Prototype Breadboard

Prototype Arduino Mega 2560

Prototype User Interface

Testing

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

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

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

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

Foot Pedal Internal pullup resistors in Atmega chip are 20 kOhm

Future Options

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

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 Final Presentation Senior Design I April 24, 2014