We are increasingly surrounded by devices that are able to communicate wirelessly with each other. What would it sound like if we could hear them talking to each other?
Audible Packets is a device that allows the wearer to hear the communication on 802.15.4 (ZigBee) wireless networks. A pair of headphones is instrumented with directionally-shielded 802.15.4 receiver boards, in enclosures whimsically styled as cartoon alien or insect antennae.
The four receiver boards (two in each antenna) listen for packets on the network. When one is received, the control electronics are able to analyze the received power level at each of the receiver boards and determine the approximate direction and distance of the transmitter. An appropriate sound can then be played in the headphones, using psychoacoustic modeling to make it seem like the sound is coming from the device that transmitted the packet.
802.15.4 transmitter boards (my prior work) with directional shielding are placed at the terminals of the "antennae", inside plastic spheres (which could be 3-D printed.) The plastic "antennae" are attached to a normal pair of headphones, and wiring to the receiver boards could run through the antenna stalks into the band of the headphones.
Another enclosure (not pictured) contains the batteries, headphone amplifier, and computating hardware for recovering the signal direction and generating sounds (a 32-bit microcontroller.)
If the format of the packets is known and unencrypted, different sounds could be generated for different message types, so the wearer could also hear the type of messages that are passing through the air.
Alternatively, rather than just listening to network activity, the device could be used to create a virtual soundscape. Transmitters placed throughout the environment could emit virtual "sounds" (really ZigBee messages) that would be inaudible unless wearing the device. The sounds would respond to the user's movement throughout the environment as he/she moved around the various transmitters withot having to do explicit localization.
The models for this assignment were produced with SolidWorks and rendered with the PhotoWorks plugin. The PCB layouts were produced with Altium and exported to 3D models. Individual components were modeled in SolidWorks.
The design of the headphone model was heavily inspired by the pair that's sitting on my desk. :)
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