The Sesenta Is a 60-Mic, Tileable Microphone Array for Acoustic Camera Projects
Using an arbitrary number of boards, this scalable mic array lends itself to everything from environmental monitoring to search and rescue.
Embedded systems specialist Andrés Felipe Calderón de Restrepo has been working on a microphone board with a difference: each multi-microphone Sesenta board is built to be tiled, offering flexibility for everything from the creation of acoustic cameras to beam-forming experimentation.
"Sesenta is a tool for [the] creation of acoustic cameras," de Restrepo explains. "Sesenta has a modular design. It consists of two parts: the microphone array and the control boards. Each array is a board with a lattice of 60 microphones designed to work in conjunction with other arrays (tile of arrays). A Sesenta array can work independently, but the ability to use it as a tile allows for an expanded range."
60 microphones is already a lot of microphones — an original Amazon Echo has, by way of contrast, an array of just seven microphones to pick up and direction-find voice commands from anywhere in a room — but de Restrepo has bigger things in store for Sesenta. Each board is designed to be connected to other boards, neatly tiling together to create an array of an arbitrary number of microphones in a range of shapes: de Restrepo has shown off a triple-board 180-mic array arranged in a triangle, a seven-board 420-mic array shaped like a hexagon, and a linear array of 360 microphones across six boards.
The microphones are designed to feed into a custom control board powered by an AMD Xilinx Zynq field-programmable gate array (FPGA) installed in a carrier board offers connectivity between modules. This mounts to the rear of the board, where it doesn't block any of the 60 microphones — each one of which listens through a hole in the PCB.
While the initial focus of the project may have been the creation of an acoustic camera — a device which captures sound, rather than light, and visualizes it — de Restrepo is clear Sesenta has a range of real-uses ranging from noise pollution monitoring and wildlife research to predictive maintenance and security. "In the event of natural disasters like earthquakes," the maker adds, "acoustic cameras might help locate trapped individuals by detecting faint cries for help."
More information on the project is available on de Restrepo's Hackaday.io page; design files are available on GitHub under the CERN Open Hardware License 2 - Strongly Reciprocal license.
