Inside the Charge 3 are an accelerometer, gyroscope, optical heart rate monitor, and an SpO2 sensor for tracking blood oxygen levels. The Charge 3 is the third Fitbit device to include an SpO2 sensor, following in the footsteps of both the Fitbit Ionic and the Versa smartwatches. However, currently the SpO2 monitor lies dormant inside all of these devices as Fitbit hasn't made use of it yet.
As of July 2013, the list of companies that were engaged in smartwatch development activities consists of Acer, Apple, BlackBerry, Foxconn/Hon Hai, Google, LG, Microsoft, Qualcomm, Samsung, Sony, VESAG and Toshiba. Some notable omissions from this list include HP, HTC, Lenovo, and Nokia. Science and technology journalist Christopher Mims identified the following points in relation to the future of smartwatches:
For deeper integration with your Android phone, you can give Google's Wear OS platform a try with Fossil's $275 Q Control touchscreen smartwatch. It lacks GPS and support for NFC payments, which is why the Gear Sport is a better fitness-focused smartwatch for Android users, but Fossil's Google Assistant integration and stylish design make it a solid contender. However, smartwatches with Qualcomm's new Snapdragon Wear 3100 processor start shipping in October, so you may want to hold off until we put them to the test.