Top view of completed ROBOEAR circuit board Top view of microphone array showing channel numbers and bearings

The ROBOEAR (Robot Ear) is designed to find the direction to nearby sound sources. In audiology this is called 'localization'. Humans can usually localize a sound to +- 10 degrees. The ROBOEAR's three microphone array can usually localize a sound to a 30 degree sector. It uses amplitude comparison and acoustic cross-correlation to localize sounds. The ROBOEAR's internal processing is done on a PIC 8-bit microcontroller. The ROBOEAR can also function as an audio acquisition front-end for more powerful computers. Communication with the host computer is jumper selectable as either serial UART, or SPI. Complete documentation can be found in the user's manual which is available for download on the Data & Documentation page.


Serial UART:
  • Serial data format: 8 bit, No Parity, 1 Stop Bit
  • Baud rates: 9600,19200,38400,76800
  • Connectors for RS-232 level or TTL level signals
Serial Peripheral Interface (SPI)
  • Jumper selectable SPI modes: 0,1,2,3
Power requirements:
  • Current consumption < 100 mA at 5 volts
  • Can operate from +5 or +9 volt DC supplies
  • On board 5 volt regulator for +9 volt operation
  • Can be connected directly to +5 volt if available
  • PIC16F1847
  • 5 volt operation at 16 MHz
Analog to Digital Converters (ADC):
  • Three MCP3001 serial ADCs
  • with on-chip sample and hold
  • Configured for simultaneous conversions
Microphone Array:
  • Three electret microphones
  • Arranged in equilateral triangle, 10 cm per side


The ROBOEAR-PCB-KIT includes all the components needed to build the ROBOEAR circuit board. The only thing you will need to supply is wire to connect the microphones to the circuit board. The items listed listed below are optional.


The ROBOEAR full kit or bare printed circuit board are available from the SERVO Magazine (T&L Publications) web store.

See the Data & Documentation page for the ROBOEAR User's Manual.

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