How BusyFit counts your reps with the iPhone camera
Updated October 31, 2026
Prop your iPhone against something, step back, and start moving. BusyFit watches your joints through the camera and counts each rep as you finish it, so you don't have to count in your head or tap the screen.
What happens on the phone
- Apple's Vision framework finds the positions of your shoulders, elbows, hips, knees and ankles in each camera frame.
- BusyFit measures the angle that matters for the move (elbow bend for a push-up, knee bend for a squat, body line for a plank) and counts a rep when you go through the full range and come back.
- A short bell plays on every counted rep and a chime when the set is done, so you can keep your eyes off the screen.
- The camera screen turns red when it can't see enough of you, and green when it's counting.
Privacy
Counting happens entirely on the iPhone. Camera frames are never saved, and they're never uploaded. BusyFit doesn't need an account.
Honest about accuracy
The counting thresholds are still being tuned across angles, lighting and body types, so BusyFit doesn't claim a validated accuracy figure. If the camera misses reps, you can log the set by hand. Hand-logged sets are marked "Logged" and camera-counted sets "Verified", so your history stays honest.
Which moves it counts
Push-up variations, squats, lunges, glute bridges, planks (held time), jumping jacks, crunches, curls, presses and more. Moves the camera can't see well, like stairs and walks, are logged from the iPhone's motion sensors or Apple Health instead.