So after having the blackvue dr650gw-2ch for a while now it annoyed me that it didn't have a manual record button. I started tapping the unit to get it to mark an event and sometimes it would do nothing but others it would say manual recording and make an event.

Since I have found out that it has a proximity sensor on the left hand side by the WiFi light. If you wave your hand in front of this it starts a manual event.

Just a quick tip incase anyone else has been looking for this.