I never was able to use the phone computer reliably. Another alternative is something from Lezyne - a Macro is $100, usually available on sale somewhere. At still lower prices you can find Brytons and IGPSports computers with ANT+ and/or Bluetooth to connect with strava, phone, or sensors, including HRMs. You don't need sensors for speed and distance, though a sensor will be slightly more accurate in many environments. Cateye does spedd, distance, and cadence at about $50, but to get HRM integration, Cateye costs more like $100 or more.