HeartyPatch supports Bluetooth Low Energy (BLE) functionality with the heartrate monitor profile giving the real-time heartrate as well as R-R intervals. This means that it is now compatible with all common heartrate monitoring and HRV (Heart Rate Variability) apps.
Here is the device working with Elite HRV, a common HRV app that is free for most uses while also having a paid version:
HRV apps such as this provide basic characteristics like heartrate, variability, signal quality (which in this case was pretty good!) and statistics such as min HR, max HR, mean, and average. HRV-specific statistics such as RMSSD, NN50, PNN50 can also be calculated.
HeartyPatch can provide calculated values from the device itself over Bluetooth or Wi-Fi (with different firmware). Below is a screenshot of the data sent by HeartyPatch to a TCP socket terminal.
If you would like to explore other HRV apps, you can search on the Google Play Store or Apple App Store for several options.
HeartyPatch, out-of-the-box, supports any Android or iOS app that supports the standard BLE heartrate profile.