The QT600 is a starter kit and development system for Atmel’s AVR 8-Bit and 32-Bit RISC Flash microcontrollers.
ATMEL QTouch Library is a royalty free software library (available for GCC and IAR compiler tool chains) for developing touch applications on standard AVR and SAM microcontrollers.
The Library can be used to develop single chip solutions for control applications which have touch sensing capabilities, or to develop standalone touch sensing solutions which interface with other host or control devices.
- USB Interface to PC
- QT600 is powered by a USB interface
- 3 MCU-boards (ATtiny88, ATmega324PA, ATxmega128A1)
- 3 sensor boards for up to 64 channels
ATMEL QTouch provides a simple to use solution to realize touch sensing solutions on a range of supported ATMEL AVR Microcontrollers. The QTouch libraries provide support for both QTouch and QMatrix acquisition methods.
Touch sensing using QMatrix or QTouch acquisition methods can be added to an application by linking the appropriate ATMEL QTouch Library for the AVR Microcontroller and using a simple set of API to define the touch channels and sensors and then calling the touch sensing API’s periodically (or based on application needs) to retrieve the channel information and determine touch sensor states.
QTouch acquisition method
The QTouch acquisition method charges an electrode of unknown capacitance to a known potential. The resulting charge is transferred into a measurement capacitor (Cs). The cycle is repeated until the voltage across Cs reaches a voltage Vih.
The signal level is the number of charge transfer cycles it took to reach that voltage. Placing a finger on the touch surface introduces external capacitance that increases the amount of charge transferred each cycle, reducing the total number of cycles required for Cs to reach the voltage. When the signal level (number of cycles) goes below the present threshold, then the sensor is reported to be in detected.
When i had to source some hard to find parts as a replacement or design component for a custom product, RS catalog was the answer.
The catalog would give an idea also of what parts are popular and summary specs. This was decades ago, now everything is Online, Datasheets, Manuals, Design resources, Application Notes.