Fitness Tracker DS-D6
https://hackaday.com/2019/08/11/fitness-trackers-dont-have-to-be-proprietary/
https://github.com/sulancheng/myble/blob/master/blelab/src/main/java/com/desay/corn/blelab/DsBluetoothConnector.java
fanoush
https://github.com/fanoush/ds-d6
https://github.com/fanoush/ds-d6/wiki/Bracelet-commands
AT+DT # Uhrzeit
Aaron Christophel
Youtube: Arduino on DS D6 Heartrate Sensor Demo
https://hackaday.com/2019/08/23/ota-flash-tool-makes-fitness-tracker-hacking-more-accessible/