Force-sensing industrial control uses QTC technology for safety-oriented panels

April 13, 2015 // By Graham Prophet
Peratech, a designer of touch technology, has created a demonstrator that uses its standard keyboard sensor together with Peratech’s Opaque QTC force-sensing technology, which accurately measures both the amount of pressure applied to the keypad and its precise location.

Peratech QTC force-sensing technology is more accurate than capacitive touch screen technology, making it much safer as it detects only actual touches so there are no false touches. As an integral part of a total HMI (Human Machine Interface) solution, QTC technology claims advantages over capacitive and other existing touch solutions – greater safety, greater accuracy, better consistency, and higher reliability, in a cost effective solution with low EMI, power, and size constraints.

Peratech’s interactive demonstration is an example of a boiler control for water volume and with temperature levels that can be controlled using the QTC custom touch panel even when wearing heavy-duty work gloves. The company says that QTC technology gives added true-force detection sensitivity that it believes no other technology can provide and performs consistently at temperatures as lower than -20C and higher than +60C. QTC technology can work behind a variety of surfaces including glass, metal, plastic, etc. giving the flexibility to create buttons, slider controls, and dials wherever on the surface we like, to configure cost-effective, customisable control interfaces.

Another key advantage of QTC force-sensing technology is that it uses less processing power compared to projected-capacitive solutions. Because QTC material changes its resistance when pressure is applied and only at the point where pressure is applied, QTC-based sensors give accurate position and pressure data that needs only minimal microcontroller processing. By contrast, Peratech says, a capacitive touch screen generally requires a more expensive microprocessor running more complex maths as it has to “make an educated guess” where applied touch occurred because it has no reference to how hard someone might have pressed the surface. The overall power budget is also less with a QTC-based solution as it only requires power when touched, unlike capacitive that always has its sensing field powered up and thus draining the battery life.

“We recently acquired a software team specifically to enable us to create HMIs,” the company adds, “This