The referee’s whistle is a tried-and-tested way of stopping play. But could it
also carry a secret burst of digital information?

The referee’s whistle is a tried-and-tested way of sending a signal to stop or
start play. But could it also carry a secret burst of digital information?

That is the question posed by Pea Whistle Steganography, a post by signals hacker Oona Räisänen which explores whether a traditional pea whistle can encode binary information in a series of frequency pulses.

The answer: yes, kind of, though constructing a physical data-encoding whistle
is left as an exercise for the reader. There is, however, some working Perl
code that synthesises a wav file containing your pea-coded message of choice.

See Oona’s blog for countless more excellent DSP explorations.


Written by the team at Chirp. We enjoy applying cutting-edge technology to interesting real-world problems, performing R &D into sound and music to create complex, robust and scalable cross-platform products. If this sounds like something you’d like to be doing, we’d love to hear from you .