Robin's Blog

Stuff that doesn't fit elsewhere

December 12, 2017 / by Robin Scheibler

FFT on the ESP32

I recently started playing with the ESP8266, which was nice but somewhat limited, and now its older brother, the ESP32. Given their price and their I2S module, they make very nice platforms to start playing with audio processing and distributed microphone arrays. Just get an SPH0645 I2S microphone and get started! Amazing.

Read more

February 04, 2014 / by Robin Scheibler

Make a custom Pomodoro timer

I have recently been interested in the ATtiny85 microcontroller. Its minimalistic, yet powerful features make it a very attractive platform for simple hacks and gadgets. In addition, I had been interested in learning the technique of charlieplexing, i.e. controlling many LEDs with very few pins. The ATtiny85, with its 5 GPIO pins available by default (sacrificing ISP yields an extra pin, but I didn’t want to go down that road), seemed like the perfect candidate.

Read more

February 13, 2013 / by Robin Scheibler

Real FFT Algorithms

Practical information on basic algorithms might be sometimes challenging to find. In this article, I break down two fundamental algorithms to compute the discrete Fourier transform (DFT, inverse transform is iDFT) of real-valued data using fast Fourier transform algorithm (FFT/iFFT).

Read more
Older Entries Newer Entries