KOGGER sonar is an affordable device that helps “see” underwater using sound waves. It can be used to find fish, search for sunken objects, and measure the distance to the seabed. The sonar sends a sound signal into the water, and when this signal encounters an object (like a fish or a piece of a sunken ship), it reflects back. The device receives this signal and, based on the time it took for the sound to return, calculates the distance to the object.

The sonar can output either raw data on the reflection levels of objects in the water for creating echograms, or provide the already calculated distance to the seabed (rangefinder mode). Visually, the echogram data might look something like this:

In rangefinder mode, the sonar analyzes the reflection levels along the entire path of the probing signal and provides the calculated distance to the seabed or to the “brightest” object in the water. The rangefinder data format can be either binary, such as bb5500410204da0200002355, or in the form of an NMEA string, like $SDDBT,2.132,f,0.65,M,0.355,F*34.

It’s worth mentioning that the sonar can perform measurements and output data either in response to commands from a controlling device (host) or autonomously at a set interval. For example, it can operate independently, providing data 10 times per second.

Let’s go over the basic settings of the 2D-Basic sonar that need to be configured for its proper operation.

Connect the sonar to the computer using a USB-UART interface converter:
Connect the sonar’s pins to the converter’s pins so that the sonar’s ground is connected to the converter’s ground, and the Tx lines are connected to the Rx lines. The sonar can be powered from the converter if the converter provides the necessary power parameters for the sonar. Launch the KoggerApp application.

To connect to the sonar using the application version 0.10.2, follow these steps:

  1. Go to the “Device & Data” menu.
  2. Select the COM port and connection speed that correspond to the connected sonar.
  3. Click the “Open” button.

When the connection is successful, a submenu with the sonar parameters appears:

Let’s consider the case where we need the sonar to send echogram data 10 times per second.
First, activate the “Echogram” parameter by switching its state from OFF to “8-bit.”
Second, set the “Period, ms” parameter to 100. This means that the sonar will automatically send data at a period of 100 milliseconds (1/10th of a second, 10 Hertz, 10 echogram slices per second):

It is also important to configure the number of points in a single measurement and their resolution.
The number of points is set by the “Number of Samples” parameter. The resolution (step size) of each point is determined by the “Resolution” parameter:

For example, if you need to obtain an echogram up to a depth of 20 meters with a resolution of 10 millimeters, set the “Resolution” parameter to 10 mm and the “Number of Samples” to 2000. Alternatively, by setting the “Resolution” parameter to 20 mm and the “Number of Samples” to 1000, you will achieve the same maximum measurement distance of 20 meters.

In other words, the maximum scanning depth equals the product of the “Resolution” parameter and the “Number of Samples.” Keep in mind that the information for each point (sample) occupies 1 byte of transmitted data. Therefore, you need to ensure that the system’s bandwidth corresponds to the amount of data being transmitted. If the channel’s bandwidth is insufficient, you can reduce the resolution (by increasing the “Resolution” parameter), reduce the number of samples, or increase the measurement interval by increasing the “Period, ms” parameter.

The last step is to select the operating frequency and the number of pulses. These are the “Frequency, kHz” and “Pulse count” parameters.
For 2D-Basic sonars, the optimal operating frequency is in the range of 700-715 kHz. The number of pulses can be left at 10:

To save the set values in the sonar’s non-volatile memory, don’t forget to click the “Flash settings” button:

That’s it! The main sonar parameters for obtaining the echogram are set, and you can see the echogram moving on the main screen.