The price of bicycle power meters is falling rapidly, with many new designs entering the market. Use is set to expand. Many of the old devices have, no doubt, old bespoked interface protocols, but -from what I understand- most of the new devices comply to 'standards' and use BLE. For example, 4iiii have just released RIGHT side power meter to go with their existing LEFT side (crank) meter which broadcasts Ant+ and BLE.