[mircemk] shows how to create a simple non-contact proximity sensor using little more than an Arduino Nano board, and a convenient software library intended to measure the value of capacitors. The … ...

Instead of measuring light, we measure the ambient voltage field on pin A5 and use it to detect if someone is too close to our Arduino. A5 is used as a “floating input”, but unfortunately it is very ...

Ki Seong Kim, Sung Soo Kim, Measurement of Dynamic TDC in SI Engines Using Microwave Sensor, Proximity Probe and Pressure Transducers, SAE Transactions, Vol. 98, Section 3: JOURNAL OF ENGINES (1989), ...