All capacitive sensors I know of, use alternating voltages at the sensor surfaces. Adjacent sensors are influencing each other. The higher their sensitivity the stronger this interaction will be.
Especially collaborative robots need multiple highly sensitive sensors in great proximity. Our technology uses fairly high frequencies to achieve high noise immunity.
To allow multiple sensors to work in close neighborhood to each other both their carrier and the test frequencies can be phase locked. The model shown in our video has two sensors synchronized with an external reference frequency. This technique can be used with any number of sensors. This way multiple collaborating robots can work together without showing uncorrelated behavior like emergency stops. Obviously, two sensors with signals 180° out of phase would force each other to issue a stop information. With different frequencies, a longer term phase difference like 180 ° is unlikely. Nevertheless, robots with nominally identical frequencies at their sensors generated by separate crystals could still show an unpredictable behavior.