Picture of Barista championship brewing stopwatch • Introduction

Upon the needs of the (2014) World Barista Championship Rules and Regulations, an adequate and precise time measuring is needed during the competition. These measurements are usually done by regular stopwatches with all the benefits (ease of use, common availability) and drawbacks (two stopwatches needed for each judge, as well as some mathematics are necessary for supervision).

This Arduino-based stopwatch originally designed to meet all the requirements of this situation, finally to make judges' work seriously simpler, yet at least as acceptalbe as the good old way. My goal were to meet the requirements of Rules and Reglations 2.2.1.H (verbosely defined under 13.3.7.). In short: during the competiton, the extraction times within each beverage category should be within 3 second variance. For example, if the competitor extracts a set of espresso drinks (four servings in two two-servings brewing), de difference between each brewing time should be less than 3 second. If first brewing is 29.1 second, second brewing should be between 26.1 and 32.1 second (excluding both 26.1 and 32.1), otherwise the competitor will get a penalty.


  • one watch instead of two,
  • designed and built to meet WBC/WCE requirements to help judges,
  • can be upgraded, changed due to the changes of Rules and Regulations and/or different type of competitions,
  • make all the measurements and analysis,
  • it's hard to be hacked by the judge to make unwanted and unfair handicaps to certain competitors (see 15.0 in Rules and Regulations),
  • easy to use,
  • planned to be upgradable to on-line/off-line logging and other features,


  • not official,
  • still a prototype.