Hi there,
and Welcome here,
Ah’ the ANT+ protocol used by other companies also but Garmin I believe owns it. There are some old threads where a gentleman purchased the ANT+ as it’s not open source. You’ll need to change the softdevice for the room to fit it as well as a bootloader if I recall.
Serch “ANT+” should yield some useful Info.
HTH
GL 
PJ 