Every person has a characteristic called capacitance. Capacitance is an electronic term that has units of measure called farads. Capacitors are electronic components that store electrical energy. A human body typically has 22 pico farads of capacitance. A result of this capacitance is often felt in the winter months via static discharges that occur when walking across a carpet and touching a metallic object. Walking across a carpet generates energy that is stored in the body’s capacitance. This energy is discharged when touching another object at a different voltage potential.
A capacitive touch sensor is basically a sensing device that measures capacitance in its environment. When a touch sensor is connected to the faucet, it first establishes a baseline level of capacitance. Once this is established, it then looks for an increase in capacitance that occurs when a person touches the faucet (the human body’s 22 pico farads). The sensor detects the increase in capacitance and either turns on water flow or turns off water flow. When the person releases the faucet, the decrease in capacitance is also detected.
Touches and grabs are distinguished by measuring the duration of the person touching the faucet. Touches are defined as being less than 300 milliseconds, and grabs as more than 300 milliseconds.
There are two capacitive touch sensors in faucets with Touch2
Technology. The first touch sensor is connected to the handle and the second sensor is connected to the spout. If a touch sensor is connected to anything conductive (wire, metal sheet, metal bar, etc.) that conductive element becomes an extension of the touch sensor.
The first sensor is attached to the handle which is made of brass. Since brass is conductive, the entire handle of the faucet is a touch sensor. The second capacitive sensor is connected to the spout. As the spout is also made of brass, the spout is also a touch sensor. However, depending on what is defined as the spout, there may be two exceptions:
- At the base of the spout is a black plastic insulating ring. It’s function is to isolate the spout from a sink. This black ring is not touch sensitive.
- The pull down wand is isolated from the spout via an insulator. Because of the isolation, the pull down wand is not touch sensitive. This arrangement is intentional to provide the most intuitive operation of the faucet.