Pulse Echo Sonar Meter

Pulse Echo Sonar Meter: An In-Depth Review of Its Capabilities

The Pulse Echo Sonar Meter is a sophisticated mobile application that transforms your Android device into a powerful acoustic measurement tool. It utilizes the device’s built-in speaker and microphone to generate sound pulses and capture their returning echoes. This data is then processed and displayed in multiple formats, including time-series waveforms, frequency spectra via FFT analysis, and detailed visual maps. The primary function of the Pulse Echo Sonar Meter is to provide an intuitive platform for exploring sonar principles, measuring distances to objects, and analyzing the acoustic properties of an environment, making it invaluable for educational and experimental purposes.

Configuring the Internal Pulse Source

Users begin by accessing the ‘Edit Pulse’ menu within the Pulse Echo Sonar Meter to configure the sound output. Here, they select the pulse type, choosing between a Single waveform, a Train of repeated waves, or a Chirp that sweeps between two frequencies. The waveform can be set to Sine or Square, and parameters like frequency, volume, and duration are adjusted using on-screen controls. Applying a Tukey or Hanning envelope softens the pulse's start and end to reduce harsh audio artifacts. This configuration directly influences the clarity and characteristics of the echo that the Pulse Echo Sonar Meter will later detect and analyze.

Acquiring and Triggering a Single Scan

To capture data, a user first selects the ‘Single’ scan mode in the Pulse Echo Sonar Meter interface. The application then waits for a trigger condition, which is met when the microphone input surpasses a user-defined pulse threshold level. This trigger can be initiated by the app’s own internally generated pulse or by an external sound source, like a hand clap, if the ‘EXT’ pulse source is selected. Upon triggering, the Pulse Echo Sonar Meter records audio for a preset sampling duration, displaying the resulting echo waveform on the main graph. This allows for precise, on-demand data collection.

Continuous Data Collection and Mapping

For ongoing analysis, the ‘Continuous’ mode in the Pulse Echo Sonar Meter automatically initiates a new scan each time the trigger condition is met. This is ideal for creating a real-time visual map. As the device is moved, each scan generates a single line of data on the map display, representing the sound intensity between the echo detection start and end markers. The gain can be adjusted up to x10,000, and pixels are colored based on either the absolute or RMS value of the signal. This function of the Pulse Echo Sonar Meter effectively builds a sonar image of the surrounding space.

Analyzing Echo Frequency Content with FFT

The Pulse Echo Sonar Meter provides robust frequency analysis through its FFT mode. After a scan is complete, the application performs a Fast Fourier Transform on 8192 data points within the user-defined echo detection zone. The resulting spectrum can be displayed as a detailed line graph or as a bar graph of third-octave bands. A key feature is the peak frequency detection, which uses a quadratic fit around the highest point for accuracy. Users can enable averaging to smooth the data, and the clear function restarts this process, making the Pulse Echo Sonar Meter a capable tool for spectral analysis.

Saving and Exporting Scan Data to CSV

Once a satisfactory scan is achieved, users can tap the ‘Save’ button within the Pulse Echo Sonar Meter to export all data. The application generates a comprehensive CSV file that includes a timestamp, the complete time-series amplitude data, and the full FFT frequency spectrum. Each file is automatically numbered and saved to the device’s storage, allowing for easy retrieval and further analysis in external spreadsheet or graphing software. This data logging capability is a critical feature of the Pulse Echo Sonar Meter for educational and research applications.

Adjusting Detection Thresholds and Ranges

Fine-tuning the detection parameters is essential for accurate results with the Pulse Echo Sonar Meter. In the settings menu, users can manually adjust the pulse and echo threshold levels, defining what amplitude constitutes a valid trigger and echo. The sampling time after a trigger can be set from 1 millisecond up to 5 seconds. Furthermore, the speed of sound used for distance calculations is configurable, allowing the Pulse Echo Sonar Meter to be adapted for different environments, such as underwater testing with a hydrophone by changing the value to 1484 m/s.