Velocity Gauge
FREESpeedometer arc from odometry, cmd_vel, or a custom field
When to reach for it
Velocity Gauge draws one speed number inside an animated arc, filled proportionally toward the configured max. Use it for at-a-glance speed during teleop. For a plotted history across multiple series, Time Series (Pro); for a bare numeric readout, Value Display.
Worked example: /odom vs /cmd_vel
Leave Topic on its default, /odom (nav_msgs/msg/Odometry), with Source on Auto: the gauge checks the topic's schema name, resolves to Odometry, and plots twist.twist.linear.x, the robot's actual velocity. Point the same widget at /cmd_vel (geometry_msgs/msg/Twist) and Auto resolves to Cmd Vel instead, plotting linear.x, the operator's commanded speed, which diverges from actual whenever the controller saturates. Custom field (Pro) reads any other numeric path, with a magnitude toggle for vectors like joint velocities or motor RPM.
Watch out for
- Auto-Detect Maxkeeps shifting the scale upward as the robot's peak speed grows, good for catching a spike but bad for muscle memory against a fixed dial. Pin Max Value for stability instead.
- When Source is Auto and the schema is not yet known, or the topic is oddly named, like
/robot/speed, it falls back to matchingodom,cmd_vel, ortwistas substrings, then defaults to Odometry if nothing matches: a silent read of 0, no error shown.
Configuration fields
The topic this widget reads data from. While connected, tap to pick from the topics the robot advertises.
Where to read the speed value from. Auto picks Odometry or Cmd Vel based on the topic's message type.
Read the gauge value from any numeric field on any topic.
WITH PROPro unlocks a "Custom field" source so the gauge can read any number on any topic, like IMU magnitudes, joint velocities, motor RPM, or throttle commands. Includes a "Compute Magnitude" toggle that treats the field as a 3D vector (with .x/.y/.z suffixes) and plots √(x²+y²+z²).
Any numeric field path to read as the speed value.
Treat the field as the base of a 3D vector and plot its magnitude.
Adapt the gauge max to the running observed maximum (with 20% headroom).
Manual gauge max.
Your own unit text shown under the value, e.g. "knots", "RPM", "%".
The color used to draw this widget.