// open on your phone, hand it to a running motor, watch the spectrum
Real-time accelerometer FFT
Uses your phone's built-in accelerometer to plot a live time-domain trace, frequency spectrum, and waterfall. Best experienced on a phone — clamp it (gently) to anything that vibrates.
Sample rate
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Window
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RMS |a|
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Peak |a|
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Dominant
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Time domain · last —— X red · Y blue · Z green
FFT spectrum · 0 – —
Waterfall · most recent at top · 0 – —
What you're looking at: the device gives us linear acceleration (gravity removed) on three axes. We square-sum to magnitude, then run a 256-point real FFT every few hundred ms. The dominant frequency in the spectrum is the loudest periodic component of whatever you're touching.
Try it on: a fan, a washing machine on spin, an electric toothbrush, your car's dashboard, a tuning fork. Don't drop the phone.
Need the real thing?
This is a toy — for production we build proper DAQ rigs with calibrated sensors, kilohertz sample rates, and synchronised channels. Get in touch.