A metronome that checks your homework. Set a target steps-per-minute, walk to the click — and because your motion sensor is listening, the display shows whether your feet are actually on it, live.
Phone in hand or trouser pocket. One click = one footfall. Within ±3 of target counts as matched — nobody walks like a robot.
For walkers, cadence is the honest effort dial: ~100 steps/min is where "moderate exercise" starts, 120+ is genuinely brisk, whatever your leg length. For runners, it's the classic overstriding fix — a slightly faster, shorter stride (many coaches drill around 170–180) tends to land feet under hips instead of out front. The usual advice is "run to a metronome and hope"; the coach closes the loop, because hoping is not a feedback mechanism.
Find your natural baseline first with a plain session or the gait rhythm test, then nudge the target up ~5% at a time. Big jumps make gaits weird.