Ultrasonic

Provides range to closest object from a single ultrasonic sensor.

Configuration

[
   {
  "type": "Ultrasonic",
  "listen_port": 8977,
  "location": {
    "x": 130.0,
    "y": 0.0,
    "z": 50.0
  },
  "rotation": {
    "pitch": 0.0,
    "yaw": 0.0,
    "roll": 0.0
  },
  "fc": 40000.0,
  "pwm_factor": 2.5,
  "max_ultrasonic_returns": 93,
  "sbr": {
      "azimuth_fov": 30.0,
      "debug_frustum": false,
      "debug_rescan": false,
      "debug_scan": false,
      "elevation_fov": 0.5,
      "ray_division_y": 5.0,
      "ray_division_z": 5.0,
      "scan_distance": 4.0
  },
}

• fc: The sampling frequency of the sensor in hertz.
• pwm_factor: The coefficient to the sampling frequency for pulse width modulation.
• max_ultrasonic_returns: The maximum number of returns from the shooting bouncing ray cast. Lower numbers will increase performance.
• sbr: JSON object specifying shooting bouncing ray parameters for the sensor.
  • scan_distance: The maximum distance the sensor will detect objects in meters.
  • azimuth_fov: The angle in the x-y plane to detect objects in degrees.
  • elevation_fov: The angle in the y-z plane to detect objects in degrees.
  • ray_division_y: The density of the return per centimeter in rays per centimeter.
  • ray_division_z: The density of the return per centimeter in rays per centimeter.
  • debug_frustum: If set to true, the frustum area will be drawn.
  • debug_scan: If set to true, the scan lines will be drawn.
  • debug_rescan: If set to true, the scan lines will be drawn only when there is an object enters the scan_distance.

Raw Output

Will return the raw ultrasonic waveform data. The format for the waveform data is an array of 32-bit floating point numbers that is the length of the requested number of samples.

{
  "targets":[
      {
        "range": 300.0
      }
    ]
} 

ranges: Array containing distance in centimeters to the closest object in front of the sensor. A value of -1 indicates no return from the sensor.

Configuration Examples

Tree Detected by Ultrasonic Sensor

Debug Frustum Enabled

Debug Scan Enabled

Debug Rescan Enabled

Comparison Between Settings

Ray Division Y

Ray Division Z