The accelerometer uses chips ADXL150 and ADXL250 as sensors (+-50g, res. 20mg) and Atmel tiny15L CPU as 10bit A/D converter and RS232 generator. MAX232 is used as voltage converter. The assembler for CPU is here. Object code was generated by nice tavrasm for Linux and device programmed via paralel port using my propietary small programmer written in C.
The device is conected via RS232 at 115kbps with Linux notebook
with my custom program written in Gtk+. It uses excelent
FFTW library to do fourier analysis of result. Spectrogram bellow
is then generated by some Perl scripts.
Whole developement took 2 years of dreaming, 1 week of planning and 1 week of work.