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emeet-pixyd

PTZ Control

The EMEET PIXY supports pan, tilt, and zoom via V4L2 controls. The daemon provides a user-friendly interface in degrees and zoom factors.

Hardware Limits

Section titled “Hardware Limits”

These ranges were verified empirically against the PIXY hardware via v4l2-ctl --list-ctrls:

Axis Min Max Unit
Pan -150 150 degrees
Tilt -90 90 degrees
Zoom 100 150 times

All values are automatically clamped to these ranges.

Absolute Positioning

Section titled “Absolute Positioning”

Bare numbers are treated as absolute:

Terminal window
emeet-pixy pan 0        # Center
emeet-pixy pan -90      # Full left
emeet-pixy pan 90       # Full right
emeet-pixy tilt 45      # Halfway up
emeet-pixy tilt -30     # Slightly down
emeet-pixy zoom 100     # No zoom
emeet-pixy zoom 150     # Max zoom

Relative Positioning

Section titled “Relative Positioning”

Use the rel prefix for relative moves:

Terminal window
emeet-pixy pan rel+10   # Pan 10 degrees right
emeet-pixy pan rel-10   # Pan 10 degrees left
emeet-pixy tilt rel+5   # Tilt 5 degrees up
emeet-pixy tilt rel-5   # Tilt 5 degrees down
emeet-pixy zoom rel+5   # Zoom in 5
emeet-pixy zoom rel-5   # Zoom out 5

Relative commands read the current position from the hardware, compute the new value, and clamp to valid range.

Web UI Sliders

Section titled “Web UI Sliders”

The web UI provides three sliders with live updates:

  • Drag a slider to send a PTZ command
  • The radar indicator updates in real time
  • The spatial position is visualized on a circular radar

Keyboard Shortcuts

Section titled “Keyboard Shortcuts”
Key Action
Arrow Up Tilt up
Arrow Down Tilt down
Arrow Left Pan left
Arrow Right Pan right
+ Zoom in
- Zoom out
C Center camera

V4L2 Details

Section titled “V4L2 Details”

Internally, the daemon communicates with v4l2-ctl:

  • Pan/tilt use pan_absolute / tilt_absolute V4L2 controls in 1/3600-degree units
  • Zoom uses zoom_absolute directly (no unit conversion)
  • The daemon multiplies user-facing degrees by 3600 before sending

After each PTZ set, a delayed (500ms) hardware readback corrects the cache with the actual motor position.

Motor Speed

Section titled “Motor Speed”

PTZ position goes through V4L2, but motor speed uses the camera’s official HID motor commands (reverse-engineered from the EMEET STUDIO protocol — see emeet-pixy.lars.software protocol docs):

Terminal window
emeet-pixy speed pan 45     # axis: pan, tilt, or zoom; value 0–10000

The web UI exposes the same control as three speed sliders in the Position card. Values are transmitted verbatim as the protocol defines them; the physical unit is being verified against hardware.

Center Camera

Section titled “Center Camera”
Terminal window
emeet-pixy center    # pan=0, tilt=0, zoom=100

This is also available as keyboard shortcut C in the web UI.

Where to go next

Section titled “Where to go next”