Many of todays fitness trackers are using a low power wireless protocol called ANT+. ANT+ was designed to allow open-access between heart rate monitors, displays, power sensors and much more. Here is a list of 661 fitness  products that use ANT+. The trouble with ANT+ is that almost all smart phones, laptops and single-board computers do not have any ANT+ hardware in them. This means if we want to pull heart rate data from a Garmin watch that is broadcasting it we are left with four options:

1. Use an existing ANT+ compatible device (ANT+ watches, bike computers, heads-up displays)
2. USB ANT stick – This will allow single board computers and laptops access speak ANT+.
3. Roll your own embedded solution using an ANT+ chip and link it with a Bluetooth / BLE device.
4. Roll your own embedded solutions using a multi-protocol ANT+/BLE chip such as the nRF52832 which is what the Arduino Primo uses.

Keith Wakeham who has been hacking ANT+ fitness devices for several years shares one solution to get ANT+ data into his phone.