In the Star Trek universe, the tricorder is a mutli-function device that is capable of doing pretty much whatever a particular episode’s plot calls for. There were multiple variants in the show, but the medical tricorder was always one of the more interesting props. As such, many toy replicas have been produced over the years, and taste_the_code’s tutorial will walk you through how to turn one into a heart rate monitor.
For this build you’re going to need some sort of hollow-body tricorder replica, though the same general concept will work with pretty much any handheld device. The project relies on a pulse sensor that actually monitors your heartbeats, which is the primary component of commercial fitness trackers. There are lots of options on the market, but most of them only cost a couple of dollars per unit.
The pulse sensor will connect to an Arduino Pro Mini, which gathers the data. Your heart rate is then displayed on a small 128x32 OLED display that communicates with the Arduino via I2C. Wiring the components up is very simple, with three wires for the pulse sensor and four for the OLED display. Just upload the provided code, crack open your tricorder replica, and find a place to mount the components. That’s it! You’ll have a nifty heart rate monitor that looks a lot more interesting than the Fitbits everyone else at the gym has.