As part of a collaboration with composer Kerry Hagan, I’ve been using Pure Data to make sound-making pillows that can be coordinated over a wireless connection, so that a dozen or more pillows in a listening space can appear to be whispering among themselves. To do this we are running Pd on a low-power processor, the Espressif ESP32, which only uses about one watt of power, including an amplifier and a tiny loudspeaker. (For comparison, a Raspberry Pi would typically dissipate between 5 and 10 watts when running Pd; this would be much harder to incorporate in a physically lightweight and compact package.)

In this talk I’ll describe the technical challenges and affordances of running Pd on very portable hardware. An advantage of the ESP32 is that the audio latency can be made much smaller than in a linux-based system such as the Pi. One major disadvantage is that memory is very tight (1/2 megabyte total) so care must be taken in designing patches for ESP32-based systems.