How Touch-Tech Faucets Work

How Touch-Tech Faucets Work

Delta Faucet asked us to do something with them and their touch-faucet technology. Of course, our first thought was: Tell us how it works. We interviewed Bob Rodenbeck, director of research and development, and here’s some of what he had to say. -Gareth

Make: Can you first give us an overview of the faucet itself? Is this the first of its kind?

Bob Rodenbeck: For more than 10 years, Delta Faucet Company has been researching and designing touch and hands-free faucet technologies. The company introduced its first electronic kitchen faucet in 2005, on the Brizo brand Pascal culinary faucet, which launched in 2006 with a combination of touch-activated and hands-free sensing.

In 2008, we introduced the first touch-activated faucet under the Delta brand (Delta Pilar pull-down kitchen faucet with Touch2O® Technology) and have since continued to expand from there. In 2011, Delta Faucet introduced Touch2O® and Touch2O.xt™ Technology (touch and hands-free) to the home bathroom. Besides convenience, electronic faucets also help reduce the transfer of messes from the hands to the faucet.

Make:Can you give us an overview of the faucets and the tech?

Bob Rodenbeck:Our Touch2O and Touch2O.xt technology were born of ethnographic research and human behavior studies to satisfy an unmet need of turning on a faucet with messy hands and turn off the water when it’s not needed between tasks.

One of the interesting things we found during our research of consumers is that while the idea of hands-free technology resonates with them, they prefer the control and responsiveness of our touch technology in the kitchen. So much activity happens in and around the kitchen sink that hands-free sensing can activate water when it really wasn’t needed. We call those surprise activations.

MAKE: How does the touch technology actually work? (We have a fairly sophisticated audience, so don’t be afraid to be technical)

Bob Rodenbeck: Every person has a characteristic called capacitance. Capacitance is an electronic value measure in farads. Capacitors store electrical energy. A human body typically has 22 picoFarads 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 pF). The sensor detects the increase 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 the faucet. The first sensor is connected to the handle and the second 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, it is also a touch sensor.

MAKE: Are there technical challenges to this type of sensing?

Bob Rodenbeck: The technical challenges we faced were isolated to a few areas: adding electronics to the faucet without taking away from the aesthetics, identifying and sourcing the right materials to ensure the technology worked as it should across a wide range of faucet styles and installations (sink material and type, water quality, installer variability, etc..), and determining the precise sensitivity to ensure the functionality was intuitive and convenient to the end user.

Our biggest challenge with this technology really had nothing to do with the technology itself and more with the mindset of users. There are certain perceptions or opinions about electronic faucets – mostly based on past experiences – we needed to overcome. By far, the largest challenge of incorporating capacitive technology into faucets was changing the perceptions and habits of faucet installers. In the case of Touch2O, the installation isn’t itself that hard, but it is different from a traditional faucet installation.

A key technical challenge involved ensuring the faucet is properly isolated from any surrounding metal (i.e. sinks) and ensuring that water (inside and outside the faucet) doesn’t affect the performance of Touch2O Technology.

MAKE: What are some of the positive benefits of this sort of technology? Disadvantages?
Bob Rodenbeck: Touch2O Technology is amazingly intuitive and extremely responsive to the user, resulting in economies of motion and ease of use. Touch2O Technology and Touch2O.xt Technology make it easier to turn on the water flow when hands are messy or turn off the water when it is not needed between tasks, potentially saving water. It also helps keep the faucet cleaner while helping to reduce the potential for cross-contamination.

The only disadvantage we’ve noticed so far is that these faucets are still relatively new and as with all new technologies and innovation platforms, there’s a certain learning curve. We’re still working to change attitudes toward electronic faucets and also address hesitations about the idea of mixing electricity and water. In reality, the technology operates on batteries and uses the energy stored in our own bodies to activate the faucet.

MAKE: Where are some of the places you see this type of technology going?
Bob Rodenbeck: There is a lot of research, collaboration and testing that comes into play when the research and development team is working on launching a new product. The R&D, design and engineering team all work together throughout the process because we believe that the collaboration results in creating better products for our consumers.

You can find touch technology almost everywhere now and continues to expand into new applications. Touch functionality is on phones, computers and other tech gadgets. But, it isn’t something you expect to see on a kitchen or bathroom faucet. Our research and development team is always looking for new applications of the technology as we aim to provide people with a better way to work with water.

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Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. His free weekly-ish maker tips newsletter can be found at

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