Taking your temperature from the inside

MIT engineers have built a 6 × 4 mm ingestible temperature sensor that fits on a one-mm2 silicon chip and detects temperature within 0.01 °C using a leakage-current oscillator powered by a 1.55 V coin cell. The device back-scatters an ultra-high-frequency radio signal to an external antenna, enabling continuous, low-power monitoring for applications such as infection detection, anesthesia tracking, fever monitoring in children, ovulation timing, and extreme-temperature exposure for athletes or soldiers.