The signal was detected using the Suzaku and XMM-Newton orbiting X-ray telescopes.

FORBES: Scientists Detect Star Being Devoured By Supermassive Black Hole

Once again, the way the particles knock electrons off the stuff they are travelling through (this time the gas) provides a useful signal (detected by the wires).

ECONOMIST: How to build a B-factory

There, its magnetic field is detected and the signal sent to a display.

ECONOMIST: Labs on a chip

For the first time, scientists have detected an oscillating signal of a star being destroyed by a supermassive black hole.

FORBES: Scientists Detect Star Being Devoured By Supermassive Black Hole

As electrons passed through the waist, the signal from the atoms was indeed detected.

ECONOMIST: Spintronics

If an arrhythmia is mild, it delivers a mild signal that may not even be detected by the patient, or that may be felt as a fluttering sensation.

CNN: Procedure could pinpoint source of arrhythmia