A method of communicating with an ingestible capsule includes detecting
the location of the ingestible capsule, focusing a multi-sensor acoustic
array on the ingestible capsule, and communicating an acoustic
information exchange with the ingestible capsule via the multi-sensor
acoustic array. The ingestible capsule includes a sensor that receives a
stimulus inside the gastrointestinal tract of an animal, a bidirectional
acoustic information communications module that transmits an acoustic
information signal containing information from the sensor, and an
acoustically transmissive encapsulation that substantially encloses the
sensor and communications module, wherein the acoustically transmissive
encapsulation is of ingestible size. The multi-sensor array includes a
plurality of acoustic transducers that receive an acoustic signal from a
movable device, and a plurality of delays, wherein each delay is coupled
to a corresponding acoustic transducer. Each delay may be adjusted
according to a phase of a signal received by the corresponding acoustic
transducer.