created 10/02/2006

last update 29/09/2007 (Daniele's link)

Paul-Nicolas created this nice robot that is capable of following the sound of a radio or a music instrument or a human voice. It uses high speed audio sampling in order to operate the interaural time detection (ITD) that is done through a fast cross-correlation process pruning erroneous results that could have been produced due to room reverberation or detection ambiguity.

Nic_1's design obviously is inspired of The robot is quoted at .

The robot's behaviour is very impressive !!! See the video (12MB - a bit too dark)


The first edition needed some improvements though. Here the better model:

Some notes:

  1. The RCX is the only micro-controller ! There is no other intelligent circuit.
  2. The controlling program has been realized with Ultimate ROBOLAB
  3. The binaural sensor is powered from RCX sensor port 1 (0) using H8 Port6,2.
  4. Both audio channels are sampled at 36kHz (300 samples per channel)
  5. Unlike normal cross-correlation the program seeks for a local minimum !
  6. The cross-correlation needs about 1.2 seconds
  7. The complete program is very simple (download in .srec format as firmware):

During the development various data-set sizes were tested. Here a data upload screen shot:

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