AS A CHILD in London, Olivia Campbell showed promise as a pianist, only to stop taking lessons before the equivalent of middle school. When the now-grown operations engineer decided to reacquaint herself with the piano late last year, she got a Lumi.

Smart instruments like the Lumi and Jamstik’s Guitar Trainer, both released last September, combine instruction via their respective apps with videogame-style exercises and scoring. The mix is sufficiently addictive that you (or your kids) might be loath to stop practicing, rather than start.

The Lumi has only 24 keys compared with a real piano’s 88. But that’s enough to teach the fundamentals. To start practicing, pull up the Lumi app on a tablet or smartphone. The app will steer you through a beginner curriculum, or let you choose from among 72 beginner-to-intermediate interactive lessons and 40 free songs. (A $10/month subscription unlocks 600-plus songs by acts ranging from the Beatles to Beyoncé, and nearly 400 exercises.)

As songs and lessons play on the app, colored bars corresponding to the keys scroll toward you on your screen. As they do, the analogous keys on your keyboard light up in the same colors, cuing you to strike them. The Lumi will score your accuracy on a note-by-note basis as if you were playing Guitar Hero, the music rhythm videogame.

Ms. Campbell dove in with the “intermediate”-level theme from “Game of Thrones.” As the notes advanced on her like an unceasing rainbow-colored throng of White Walkers, she realized she might have been “a bit too ambitious.” Still, she says, “it’s all about practicing making perfect.”