DIY Fitness Tracker

Tracking workouts without a smartwatch using native iOS features

May 11, 2024 - Willem L. Middelkoop

As a little side-project, squeezed between my normal work, I have been working on something of personal interest: a native workout tracking app for iOS. I wanted to make my smartwatch obsolete, instead using my phone to track workouts. How hard could it be to gather detailed sensor data using native Swift APIs?

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Early prototype of the app working with Bluetooth heartrate sensor and its early dataset shown in another app that makes some pretty graphs (HealthFit)

My bike with Bluetooth sensors connected to my MacBook running Xcode

Screenshots of the app's onboarding process: asking for permissions and guiding new users

I used my Garmin Edge data layout as an inspiration when designing my app's layout when used as mounted bike computer

"Goin' the extra mile": 8 hours on my bike to test battery usage (note: there is still 23% power left!)

I got some magic in my pocket: The app tracking workouts from the background - during recordings it just shows a widget on the homescreen

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Articles (162)

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2025-03-06 Open-Sourcing Gran Fondo
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