Pulse Echo Sonar Meter

Real Talk: What This Sonar Meter App Actually Does for Acoustic Experiments

I first grabbed Pulse Echo Sonar Meter out of curiosity—wanted to see if my phone could double as a basic acoustic rangefinder. Honestly, it does exactly that, but with a steep learning curve. The app sends out a sound pulse through your phone’s speaker (or an external source), listens for the echo via the microphone, and then visualizes the return signal as a waveform, a Fourier transform graph, or a time-lapse map. It’s not a toy for instant room measurement; it’s more like a portable lab tool for understanding how sound reflects, attenuates, and behaves in different spaces.

Customizing Your Pulse: Single, Train, Chirp, and the Envelope Settings

What sets this apart from a simple oscilloscope app is the depth of pulse generation. You can pick between sine or square waves, apply a Tukey or Hanning envelope to soften the start/end, and choose a single burst, a train of N repeats, or a chirp that sweeps between two frequencies. I spent an afternoon just comparing how a 1 kHz square wave with a Tukey window sounds versus a 440 Hz sine chirp—the difference in echo clarity is dramatic. The pulse duration goes up to one full second, and the frequency range from 20 Hz to 22.05 kHz covers both audible and near-ultrasonic. One catch: on many phone speakers, the waveform gets distorted by speaker startup noise, so the “clean” pulse you set in the edit menu often comes out as a harsh click. The app’s own guide admits this, and I found that the click actually works fine for triggering scans—just don’t expect a pure tone.

Waveform Display, FFT Analysis, and the Map Feature for Movement

The main screen shows the time-series echo trace in cyan (latest), white (previous), and grey (older). You can pan by touching and dragging the graph, and adjust the vertical scale from 0.005% to 50% per division. The lower display offers three modes: Map, FFT, and Trace. The Map mode is the most visually interesting—each new scan adds a horizontal line, so if you move the phone across a room, you can build a cross-section of reflective surfaces. Pixel values can be RMS or absolute, and the gain runs from 1x to 10,000x. It’s not clinical sonar imagery, but it works for crude obstacle detection. The FFT uses 8192 points with a Blackman window, and you can view results as a line graph or as third-octave bars. I found the FFT averaging helpful for reducing noise when measuring a steady tone from a speaker. However, the peak frequency detection uses a quadratic fit around the highest bin—it’s decent but not precision-grade.

Data Logging and CSV Export for Further Analysis

Every scan can be saved as a .txt file (actually CSV format) with time-series samples, FFT data, and third-octave levels. The files land in the root directory as “Pulse Echo Sonar Meter Data File00000.txt” with auto-incrementing numbers. Inside, you get a timestamp, sample rate (44.1 kHz), and columns for sample index and amplitude percentage. The FFT section lists frequency steps (about 5.38 Hz per bin), the peak frequency, and peak dB. I’ve used this to compare echo decay times in different rooms—exporting to a spreadsheet is straightforward. One limitation: the WRITE_EXTERNAL_STORAGE permission is required, and on newer Android versions you need to grant file access explicitly. Also, the number of samples per file can get large (up to 5 seconds at 44.1 kHz is ~220,500 points per scan), so repeated saves fill up storage fast.

Honest Drawbacks and Real-World Use Cases

No tool is perfect, and Pulse Echo Sonar Meter has clear limits. First, the microphone on most phones is not sensitive enough to catch weak echoes from more than a few meters unless the surface is highly reflective (like a concrete wall). I tried measuring a doorway 6 meters away in a quiet hallway—barely a visible echo. Second, the internal speaker output is often too quiet for long-range work, and the app’s maximum volume still goes through your device’s volume control, so you may need an external amplifier. Third, the interface is cluttered with buttons for settings, pulse editing, and display modes, all crammed on a small screen. It took me several sessions to memorize where everything is. The app explicitly states it’s for “indication only” and not for medical or ultrasound imaging—don’t expect medical-grade accuracy. If you’re a hobbyist building a simple acoustic rangefinder or teaching wave physics, this tool gives you raw data and control. For casual room measurement, a dedicated ultrasonic sensor module would be easier.

Who Should Download This Acoustic Pulse App?

If you enjoy tweaking parameters and understanding signal processing at the expense of convenience, Pulse Echo Sonar Meter is a worthwhile download. Students learning about sound reflection, FFT, and time-of-flight measurement will get hands-on insight. But if you need a quick “measure room size” app with a single button, look elsewhere. The app requires patience: you set the pulse threshold level, echo threshold, sampling time, and trigger mode (single or continuous), and then interpret the resulting waveforms. I’ve used it to illustrate how chirp pulses reduce interference compared to single-frequency bursts—something that’s hard to demonstrate with just theory. The continuous mode can be noisy because it triggers on any sound crossing the threshold, so background chatter will ruin a scan. Ear protection is a real recommendation; I accidentally left a 2 kHz square wave train running for ten seconds and regretted it.

Ultimately, this is a niche utility for the curious, not a polished consumer app. The value proposition is in the depth of control: you can generate custom pulses, apply envelopes, choose data display modes, and export raw results. The limitations—weak microphone sensitivity, distorted speaker output, clutter UI—are honest and documented. If you can work around them, you’ll learn more about acoustics than any paid app ever taught me.