External Trigger

← External Signals

Supported on DELTA-01 and DELTA-10. Use an external input to capture one frame, a fixed number of frames, or a continuous stream.

Connect the input

Use the right-hand rear SMA port on DELTA-01, or M8 pin 2 (Trigger In) on DELTA-10. See Camera Interfaces for the connector diagrams.

Signal-generator setting Value
Amplitude 1.8 V peak-to-peak: 0–1.8 V
Offset 0.9 V
Frequency Required trigger rate
Duty cycle 50%
Waveform Square wave

Capture setup

  1. In DVS Viewer, stop acquisition and recording, then open Sensor Settings.
  2. Under External trigger, choose Single, Burst, or Burst single.
  3. Set Trigger condition to Rising edge, Falling edge, or Any edge. For Burst single, also set Frames per trigger.
  4. Start acquisition. The sensor waits for the selected input condition.
Sensor Settings · External trigger
External trigger menu showing Not used, Single, Burst, and Burst single
Choose a capture mode in the External trigger menu.

With Any edge, both transitions count: a square wave at f Hz produces 2 × f trigger edges per second. Allow a complete frame or burst to finish before the next selected edge; an early trigger can cut off late-read columns.

Timestamp and frame index

With acquisition and recording stopped, choose Timestamp or Frame index under External trigger → Metadata. This changes the metadata attached to the sensor data, not the trigger condition or the number of frames captured.

Metadata mode What it records Use it for
Timestamp Elapsed sensor time Measuring capture times and intervals
Frame index Sensor capture counters Identifying capture order and comparing trigger responses

Timestamp is generated by the sensor; it is not the time when USB data reaches the computer. Its time scale depends on the configured sensor clock and counter units.

Frame index identifies capture order; it is not a duration. In Single mode, it advances for each captured frame. For burst capture, interpret it together with the selected mode and frames per trigger.

Capture timing

Capture timing · Rising edge examples
Timing examples: Single produces one scan per rising edge; Burst single produces four scans per rising edge; Burst continues scanning after the first rising edge
Conceptual timing, not to scale. Burst single is illustrated with N = 4.

Choose a capture mode

Single — one frame per trigger

Select Single in the Viewer. Each selected input edge captures one frame, then the sensor waits for the next edge. Use it to align individual frames with an external device or periodic signal.

Burst — continuous capture after one trigger

Select Burst. The first selected edge starts continuous capture; further edges are not needed to keep it running. Stop acquisition in the Viewer to end capture.

Burst single — a fixed number of frames per trigger

Select Burst single and enter Frames per trigger. Each selected edge captures that number of frames, then the sensor waits for the next edge. Leave enough time for the complete burst before sending another trigger.

Select the input condition

Choose Trigger condition in the Viewer:

Condition Responds to
Rising edge Low-to-high transition
Falling edge High-to-low transition
Any edge Both transitions

Global Reset and Global Hold

The Viewer applies the capture settings for the selected trigger mode. Single and Burst single use Global Reset with Global Hold; Burst keeps Global Reset disabled for continuous capture.

Global Reset synchronizes the pixels' brightness-reference update, while Global Hold fixes their measured event states at one instant. These sensor-internal functions are separate from the external trigger, which aligns the start of a frame with the input signal.