Capacitive dongle for visualization devices including a capacitive touch-sensitive surface

A visualization device including a capacitive touch-sensitive surface capable of exchanging data with a capacitive dongle, the dongle being arranged on said capacitive touch-sensitive surface in operational use, the dongle operating in send mode and in receive mode, wherein the dongle includes at least:

• means for sending periodic analogue signals said signals being sent at least one specific frequency known as the dongle frequency;
• a ring-shaped fiat conductive metal part connected to said sending means, said part intended to be placed on said capacitive touch-sensitive surface;
• means for receiving the received signals output by said conductive metal part;
• means for analyzing said digitized received signals;
• means for storing the sent signals and the analyzed signals;
• and
• a digital communication interface, said touch-sensitive surface including a matrix of conductive rows and columns, wherein the capacitive touch-sensitive surface includes:
• means for recognizing a determined profile corresponding to the variations in capacitance induced on the rows and columns of the matrix by the ring-shaped flat conductive metal part, when the dongle is placed on said touch-sensitive surface;
• means for sending and receiving at the specific dongle frequency.

A method of communication between a capacitive dongle and a visualization device, wherein the visualization device includes a capacitive touch-sensitive surface capable of exchanging data with the capacitive dongle, the dongle being arranged on said capacitive touch-sensitive surface in operational use, the dongle operating in send mode and in receive mode, wherein the dongle includes at least:

• means for sending periodic analogue signals, said signals being sent at least one specific frequency known as the dongle frequency;
• a ring-shaped flat conductive metal part connected to said sending means, said pad intended to be placed on said capacitive touch-sensitive surface;
• means for receiving the received signals output by said conductive metal part;
• means for analyzing said digitized received signals;
• means for storing the sent signals and the analyzed signals;
• and
• a digital communication interface said touch-sensitive surface including a matrix of conductive rows and columns, wherein the capacitive touch-sensitive surface includes:
• means for recognizing a determined profile corresponding to the variations in capacitance induces on the rows and columns of the matrix by the ring-shaped flat conductive metal part, when the dongle is placed on said touch-sensitive surface;
• means for sending and receiving at the specific dongle frequency;
• wherein, when the dongle is placed on the capacitive touch-sensitive surface, said method includes the following steps:
• Step 1:
• Recognition, by the recognizing means of the touch-sensitive surface, of the determined profile of the ring-shaped flat conductive metal part of the dongle;
• Step 2:
• Recognition by the detecting means, known as “envelope detection”, of the dongle, of the signals sent by the touch-sensitive surface in operation;
• Step 3:
• Preparation of the dongle operating mode of the touch-sensitive surface, the sending means switch to the mode for sending the dongle frequencies and the receiving means of the touch-sensitive surface switch to the mode for receiving the dongle frequencies;
• and
• Step 4:
• Operation in dongle mode, the touch-sensitive surface and the dongle exchange signals at the dongle frequencies.