Tiny ingestible thermometer provides continuous core body temperature readings

MIT engineers have developed a millimeter-sized ingestible sensor that measures core body temperature with high accuracy. The device uses a low-power circuit and backscattering to transmit data to an external antenna, and it could be used to monitor infections, fevers, and other conditions. The researchers hope it will eventually replace traditional thermometers.

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The sensor's core is a silicon chip that exploits leakage current—the small electrical flow present when a circuit is off—to create an oscillator whose frequency shifts with surrounding temperature. This design achieves 0.01°C precision while consuming minimal power. A backscattering technique transfers most energy demands to an external antenna, which emits ultra-high-frequency radio waves that the sensor modulates and reflects back, enabling temperature calculation from the wave's alterations.

Existing ingestible temperature monitors are too large for comfortable swallowing and carry gastrointestinal obstruction risks. The MIT device, measuring just 6 by 4 millimeters, is described by researchers as the smallest ingestible temperature-sensing capsule they have encountered