Piezo-ceramic switch for human-machine interfaces in white goods

Paul Boughton

Following an extensive research and development programme, Barantec has obtained approvals for its piezo human machine interfaces (HMI) unit to be used in white goods.

The durability and environmental resistance of Everswitch patented piezo switches has led to their use in many tough-duty applications, both outdoors in high traffic areas and in industrial control panels.
Furthermore, because they are resistant to tampering and vandalism, the Everswitch piezo modules can also be found in unattended applications such as ATMs, vending machines and security access/entry devices.
With no moving parts, Everswitch piezo switches offer high reliability and incredibly long life.
Now Barantec, the developer of the Everswitch line of piezo human machine interfaces devices, has pushed the reliability factor even further by electrically linking the piezo-ceramic element to the circuit board using anisotropic conductive rubber, rather than soldering or using adhesive.
This patented innovation, says Barantec, eliminates the need for soldered connections and avoids placing any thermal stresses on the ceramic material.
As a result, the Everswitch piezo HMI can now endure more than 50 million actuations.
To extend the versatility of Everswitch piezo technology even further, Barantec has developed a acontinuous' version of the piezo ush point by designing a signal-conditioning circuit that is able to detect the presence of the user's finger on the push point beyond the initial momentary contact.
This technology can now be found in a sleek and stylish cooktop/range hood, produced by Siemens in Germany, where it is used to control fan speed and illumination.
The hood features five Everswitch piezo pushbuttons controls, each replacing mechanical switches that were used in earlier models.
Siemens chose Everswitch piezo or two reasons: first, the sealed switching technology will be impervious to the daily onslaught of steam and grease from cooking; and secondly, flush mounting complements the sleek appearance of the hood's aesthetic design.
The integration of the Everswitch piezo HMI was successful and the company is now working to integrate Everswitch piezo switches into a new cooktop that will be introduced next year.
The continuous piezo switches in the cooking appliance will be used to control heat level and will replace optical and capacitive switches.

For more information, visit " target="_blank">www.everswitch.com