US Patent 11189321 Retrospective capture trigger

An event marking device marks the real time at which notable events occur. When a notable event occurs, a user causes the event marking device to generate a trigger signal. The event marking device includes a real-time clock. When the user causes a trigger signal to be generated, a microcontroller of the event marking device reads the real-time clock and writes trigger event data to a memory indicating a real time at which the trigger signal was generated. The event marking device outputs the trigger event data to an external device.