What is cardiometer?

CardioMeter is a straightforward app that connects to a Bluetooth heart rate monitor and shows your live heart rate on screen. It's built for people who exercise with a chest strap or armband sensor and want a clean, no-frills way to track their pulse during a workout. The app displays your current heart rate in real time and shows a five-minute history plot so you can see how your effort has trended over the past few minutes. It also reads out RR intervals, which are the milliseconds between each heartbeat, a metric that exercise enthusiasts and researchers sometimes use to gauge fitness and recovery. On top of that, you can set up five customizable heart rate zones based on your Heart Rate Reserve, which is the range between your resting and maximum heart rate. This lets you see whether you're in an easy, moderate, or hard effort zone at a glance. The target user is someone who already owns a Bluetooth LE heart rate monitor and wants a lightweight app to display their data without the clutter of a full fitness tracking platform. A runner doing interval training could use it to stay within specific heart rate zones. A cyclist could check the history plot to see if their heart rate drifted up during a long climb. Someone doing zone-based endurance work would get value from the configurable zones and RR interval readout. The project is built in C# and is open source under the Apache 2.0 license, meaning anyone can use, modify, or distribute it freely. The README doesn't go into detail about which platforms it runs on or how to install it, so you'd need to look at the repository itself for those specifics.