Differentiation of Fencing Blade Alloys Using iPhone Magnetometer

  • Lucas Chen West Coast Fencing Academy


All modern fencing sabers are made of composite steel alloys with variable stiffness and tensile strength. Blade differentiation is often difficult due to similar weight, color, and appearance, yet blade quality is of utmost importance as Olympic fencers have died from broken blades. Traditional methods of steel alloy identification involve spectrometry or machine tensile strength assessment, which are impractical in a competition arena. Since all modern smartphones have built-in magnetometers to detect the Earth’s magnetic field as a component of GPS and location services, we previously patented the utilization of the smartphone magnetometer to differentiate fencing steel alloys. This manuscript now reports the experimental protocol necessary for the novel application.


DOI: http://dx.doi.org/10.30609/JETI.2020-9096

Author Biography

Lucas Chen, West Coast Fencing Academy

Saber Fencer, Junior Olympics

United States


International Olympic Committee. Fencing: History of Fencing at the Olympics Games. Olympics Studies Centre. March 2015.

AZOM. Advanced Materials in the Sport of Fencing. AZO Materials. March 15, 2001.


Science Encyclopedia. Steel: Raw Materials. Downloaded September 18, 2019.


Smith, William F, Hashemi, Javad. Foundations of Material Science and Engineering. McGraw-Hill, 2001. p. 394

Vericheck Technical Services. Common Metal Detection Methods. December 1, 2016.


Wallulis, Karl. List of Metals That Are Attracted to Magnets. April 17, 2018.


TechBlog. Using techBASIC to Turn Your iPhone or iPad into a Metal Detector. November 30, 2011 http://www.byteworks.us/Byte_Works/Blog/Entries/2011/11/30_Using_techBASIC_to_Turn_Your_iPhone_or_iPad_into_a_Metal_Detector.html

Chen, Lucas. Determining Fencing Blade Quality using Dynamic Magnetic Field Measurements. The United States Trade and Patent Office, U.S. Serial Number 16/422,731. May 24, 2019.