Haptics Touch Screen Interface
April 21, 2011 We talked with Patrick Hanley, product marketing manager from Atmel about their new haptics interface and capacitive touch interface. This product addresses the challenge of missing feedback in touch applications. The current software processes of adjacent key selection discrimination, next letter anticipation, and proximity enlargement give some slow-response visual feedback. The problem is that these mechanisms only provide some visual feedback and don’t tell you if you actually pushed the key.
The AT421QT1085 (way too long a part number, internally they call it the QT1085) uses some technology IP from Immersion to provide tactile feedback to the user. The part has a repertoire of 14 haptic effects for up to 8 channels of input. The part, plus an additional bidirectional motor amplifier/controller, drives an eccentric motor-driven weight to create vibrations.
The company has a number of electrical and mechanical recommendations for the systems, as the mounting and location of the motor assembly is fairly critical. Handheld devices should have the motor located near an edge, while mounted touch panels should have the motor mounted near the center of the display. Depending upon application, the chip needs a separate driver for the motor.
When questioned about the lack of an integrated amplifier/driver, the response was that there are too many variables in the implementation to allow for a single amplifier. Different motors require different drive characteristics and the need for a bidirectional, overdrive-capable driver that is matched to the motor requirements is critical for response time.
Parts, evaluation kits, and data sheets will be available early in May. For more information, go to their website
