Human Machine Interface (HMI) solutions are critical across water-based applications. From sanitary controls in healthcare environments to submerged interfaces in pools and spas, these systems must operate reliably in some of the harshest conditions while remaining intuitive for users. 

As expectations around durability, hygiene, and design continue to rise, solid-state piezo touch technology is emerging as a game changing solution, delivering performance advantages that traditional mechanical and capacitive interfaces struggle to match. 

This article explores how piezo technology is revolutionising two key application areas: underwater pool systems and sanitary controls. 

The Challenge of Water-Based Interfaces 

Water applications place unique demands on HMI components. Interfaces are often exposed to moisture, temperature fluctuations and chemical treatment. They also have strict hygiene requirements. 

Traditional switches, which rely on moving parts and mechanical seals, are inherently vulnerable in these environments. Over time, seals degrade, components wear, and performance deteriorates which leads to maintenance issues and reduced product reliability. 

Touch-based technologies have become increasingly popular thanks to their durability, ease of cleaning, and modern appearance. Solid-state solutions with no moving parts offer significantly longer lifecycles and improved reliability compared to mechanical alternatives.  

Submerged Pool & Spa Controls: Reliability Under Pressure 

Modern pool design, especially with the rise of counter-current swim systems, places control interfaces directly underwater. These panels typically manage the speed and direction, on/off control and lighting functions. 

Installed flush into the pool wall and permanently submerged in treated water, these interfaces are extremely difficult to access for maintenance. That means failure is not an option. 

This creates a unique category of HMI requirement: 

  • Fully sealed, long-life construction
  • Resistance to chemicals and water ingress
  • Consistent performance over years of use
  • Intuitive operation for users in water

Piezo Technology is ideal as solid-state piezo switches have no moving parts, eliminating wear and mechanical failure. It also allows sealed construction (up to IP69K), protecting against water ingress and harsh environments. The switch can sense through the surface material, whether that be stainless steel, glass or polycarbonate and contain LED feedback visible underwater. All with high durability ensuring the long service life demanded in these applications. 

In addition, innovations such as the PT Plus intelligent switch platform allow multiple functions to be controlled through a single cable, simplifying system architecture and reducing internal wiring complexity.  

For manufacturers of premium pool and spa systems, this shifts the HMI from a potential weak point to a true product differentiator. 

Sanitary Controls: Simplifying Hygiene Critical Systems 

Sanitary applications, such as healthcare washrooms and public facilities, present a different but equally demanding set of challenges. 

Traditionally, these systems rely on: 

  • External control boxes or PLC cabinets
  • Separate components for flush logic and valve control
  • Additional wiring, sealing points, and installation effort

This not only increases system complexity and cost but also introduces more potential failure points. 

Piezo-based sanitary switches with integrated intelligence offer a more efficient solution. Advanced units such as the PTF-22-PDC embed control functionality directly within the interface, enabling programmable hygiene flush cycles (e.g. 24, 48, 72 hours) with adjustable flow time and lockout settings. The unit also allows direct control of solenoid valves (latching or non-latching) and operation via battery or mains power. 

By eliminating the need for external control boxes, these solutions: 

  • Reduce bill of materials (BOM)
  • Simplify installation
  • Minimise sealing requirements
  • Improve overall system reliability

With ultra-low standby power, USB configurability, and robust sealing (up to IP69K), they are designed for demanding, hygiene-critical environments. 

The Broader Benefits of Piezo Touch Interfaces 

Across both underwater and sanitary applications, the key advantages of piezo and touch switching technologies are clear: 

  • Long operational life due to solid-state design 
  • Ease of cleaning and hygienic surfaces 
  • High resistance to water, chemicals, and impact 
  • Modern, premium aesthetic enhancing product design
  • Reduced maintenance and system complexity

Turning the Interface into a Competitive Advantage 

In demanding water-based environments, the interface is more than just a control point—it is where users directly experience the quality of a product. 

By adopting solid-state piezo technology: 

  • Reliability increases
  • Maintenance decreases
  • Design flexibility improves
  • Product value is enhanced

For OEMs and system designers, this represents a significant opportunity to differentiate their products in competitive markets. 

Partnering for Next-Generation HMI Solutions 

Diamond HMI provides advanced PiezoTouch solutions tailored for water, sanitary, and industrial applications.  

If you are looking to improve reliability, simplify system design, or elevate your product interface, now is the time to explore the benefits of piezo technology. 

Contact Diamond HMI today to discover how your next design can take advantage of this technology revolution.