A device such as a dental cuspidor or a dental delivery unit, with an electric field sensor, control circuitry, and a solenoid. The control circuitry is in electronic communication with the electric field sensor, and the solenoid is in electronic communication with the control circuitry. The electric field sensor has capacitive sensing and is operable to detect a change in capacitance. The control circuitry is operable to receive a signal from the electric field sensor indicative of a detected change in capacitance. The control circuitry is operable to actuate the solenoid in response to receiving the signal from the electric field sensor. A method is also provided.