Abstract: A touch panel includes capacitive sensing electrodes and a touch controller operates in a first operating mode to detect a touch location on the touch panel. In a second operating mode, the touch controller transmits a modulated data signal through the touch panel to an active stylus. Each electrode is driven by a line driver circuit. A control circuit selectively actuates first ones of the line driver circuits to pass the modulated data signal to corresponding first ones of the electrodes which do not pass through a region of the touch panel associated with the location of the detected touch. Simultaneously, the control circuit selectively actuates second ones of the line driver circuits, different from said first ones of the line driver circuits, to ground corresponding second ones of the electrodes which do pass through the region of the touch panel associated with the location of the detected touch.

Abstract: Capacitance sensing circuits and methods are provided. The capacitance sensing circuit includes a capacitance-to-voltage converter configured to receive a signal from a capacitance to be sensed and to provide an output signal representative of the capacitance, an output chopper configured to convert the output signal of the capacitance-to-voltage converter to a sensed voltage representative of the capacitance to be sensed, an analog accumulator configured to accumulate sensed voltages during an accumulation period of NA sensing cycles and to provide an accumulated analog value, an amplifier configured to amplify the accumulated analog value, and an analog-to-digital converter configured to convert the amplified accumulated analog value to a digital value representative of the capacitance to be sensed. The analog accumulator may include a low pass filter having a frequency response to filter wideband noise.

Abstract: According to one embodiment of the present disclosure, a touch controller is adapted to be coupled to a touch screen and to a motion sensor. The touch controller is operable in response to a signal from the motion sensor indicating a first motion to switch from a hover event sensing mode of operation to a gesture event sensing mode of operation. In one embodiment, the touch controller is operable in the hover event sensing mode of operation to detect a first hover event and is thereafter operable, in response to the signal from the motion sensor indicating a first motion has occurred, to switch to the gesture event sensing mode of operation and detect a first gesture event.

Abstract: A system for securely controlling access between two wireless (i.e. Bluetooth-enabled) apparatuses, also comprising a supervisor apparatus. The first apparatus is paired to the second by establishing a secure wireless (i.e. Bluetooth) link The first apparatus includes a stored partial link key and a link key generator: The first apparatus receives a first secret key from the apparatus user, and may also receive a second secret key from the supervisor apparatus. The link key generator generates either a first link key based upon a stored first partial link key, the first secret key and the second secret key or a second link key based upon the stored first partial link key and the first secret key. An access control module in the second apparatus determines the level of access that the first apparatus is granted based upon the link key used to establish the secure connection—full/restricted access.

Abstract: A capacitive discharge circuit includes a line having a capacitance, a switched capacitor circuit including a capacitor, a switched circuit coupled to the line, and a voltage regulator coupled between the switched capacitor circuit and the switched circuit. A controller operates the switched capacitor circuit and switched circuit to in a first phase, charge the capacitor by coupling the capacitor between a common mode and a power supply, and in a second phase, discharge the capacitor by coupling the voltage regulator in series with the capacitor between the power supply node a ground. The controller is also configured to in a third phase, charge the capacitor by coupling the capacitor between the common mode and the power supply, and in a fourth phase, share charge between the line and the capacitor by coupling the voltage regulator and the capacitor in series between the line and the ground.

Abstract: An active stylus is capacitively coupled to a capacitive touch panel for communication. The active stylus operates in a wait mode to receive initial communications from the panel. In response to such receipt, the active stylus synchronizes to a repeating communications frame implementing time division multiplexing. Communications from the active stylus to the panel include: information communications; synchronization communications and communications specific for columns and/or rows of the panel. Communications from the panel to the active stylus may be addressed uniquely to the stylus or commonly to a group of styluses.

Abstract: A capacitive sensing analog front end for a touchscreen system having an improved signal-to-noise ratio includes a capacitance-to-voltage converter having an input for coupling to an external sampling capacitor, a summer having a first input coupled to an output of the capacitance-to-voltage converter, a low pass filter having an input coupled to an output of the summer and an output for providing an output signal; and a sample-and-hold circuit having an input coupled to the output of the low pass filter and an output coupled to a second input of the summer. The signal-to-noise ratio of the touchscreen system is improved by extracting the DC shift of a touch signal during a monitoring period and then subtracting the DC shift before integrating the touch signal.

Abstract: Disclosed is keypad circuitry operable to detect a pressed key while reducing electromagnetic interference (EMI). The keypad circuitry is operable to reduce EMI in two ways: a) reducing the voltage swing occurring at the row circuitry and column circuitry of the keypad, and b) reducing the number of signal transitions by restricting the signal transitions to occurring at the column and row corresponding to a pressed key. By limiting signal transitions to occurring only at the row and column corresponding to a pressed key, fewer signal transitions occur, and thus, less EMI is produced. Additionally, reduced voltage swings at the row circuitry and column circuitry results in reduced EMI.

Abstract: A capacitive proximity sensor circuit capable of distinguishing between instances of detected user proximity includes one or more guard electrodes, a first sensor, and a second sensor. The capacitive proximity sensor is installed in a device such that a first sensor faces a first component of the device, and the second sensor faces a second component of the device. The first and second sensors measure a capacitance to detect proximity of a user relative to the respective sensor. The guard electrode is provided to mitigate stray capacitance to reduce error in the capacitance measurements obtained by the first and second sensors.

Abstract: A security monitoring device for recording security footage at a location, the device comprising: a controller to control the device; a camera for obtaining security footage of the device surroundings; a location information device adapted to provide location information to the controller; storage for storing the security footage along with other information, the other information including at least time and location and being stored separately to the security footage but being associated by time; and communication means for the controller to communicate with a central monitoring system; wherein the device is configured to analyse the other information at the device prior to communication of information and/or security footage to the central monitoring system.

Abstract: A directional capacitive proximity sensor circuit capable of providing directional capacitive proximity sensing includes one or more guard electrodes, a first sensor, and a second sensor. The directional capacitive proximity sensor is installed in a device such that the first sensor is positioned near a first component of the device, and the second sensor is positioned near a second component of the device. The first and second sensors measure a capacitance to detect proximity of a user relative to the respective sensor, wherein the detected proximity is interpreted to determine a direction in which the user proximity is detected relative to the directional capacitive proximity sensor circuit. The guard electrode is provided to mitigate stray capacitance to reduce error in the capacitance measurements obtained by the first and second sensors.

Abstract: A touch screen having a capacitive touch-sensitive pad overlaying a display area incorporates one or more slide features each having conductive plates. The conductive plates are located outside the display area of the touch screen and are powered via one or more connections to existing touch sensor circuitry comprising the touch-sensitive pad. The slide features of the touch screen do not obstruct a user's view of the display screen and, when compared to conventional touch screen slide features, reduce the circuitry required for detecting and/or processing a slide touch.

Abstract: A touch screen device having a touch screen panel and a method for operating a touch screen device are provided. The method includes monitoring, during a noise monitoring phase, channel signals of a first set of channels and a second set of channel of the touch screen panel, detecting a stylus signal in response to a channel signal greater than a stylus threshold and less than a palm threshold, selecting the first set of channels when the stylus signal is detected on at least one channel of the first set of channels and is not detected on the second set of channels, and selecting the second set of channels when the stylus signal is detected on at least one channel of the second set of channels and is not detected on the first set of channels.

Abstract: According to one embodiment of the present disclosure, a touch controller is adapted to be coupled to a touch screen and to a motion sensor. The touch controller is operable in response to a signal from the motion sensor indicating a first motion to switch from a hover event sensing mode of operation to a gesture event sensing mode of operation. In one embodiment, the touch controller is operable in the hover event sensing mode of operation to detect a first hover event and is thereafter operable, in response to the signal from the motion sensor indicating a first motion has occurred, to switch to the gesture event sensing mode of operation and detect a first gesture event.

Abstract: A system and method for synchronizing two devices in communication with each other. When communication between the two devices is to be established, a synchronization process may be invoked. In an embodiment, a first device may initiate sending synchronization signals having rising edge and falling edge pairs. The second device may include a controller configured to receive the synchronization signals. However, noise may inhibit the ability of the controller to correctly receive and/or interpret the synchronization signals. Noise may cause detection components to falsely detect noise as a synchronization signal or may cause detection components to miss detection of an actual synchronization signal. A window generator may be used to generate comparison windows for the controller to detect synchronization signals.

Abstract: A current source includes a first current path including a first current mirror transistor and an input current source coupled in series, a second current path including a second current minor transistor, wherein control terminals of the first and second current minor transistors are connected, a first circuit configured to provide a controlled auxiliary current in the second current path, and a second circuit configured to provide a controlled output current in the second current path when or after the auxiliary current has reached steady state. The current source may include one or more cascode transistors in the first current path and one or more cascode transistors in the second current path. The first circuit may be activated before the second circuit is activated.

Abstract: Capacitance sensing circuits and methods are provided. The capacitance sensing circuit includes a capacitance-to-voltage converter configured to receive a signal from a capacitance to be sensed and to provide an output signal representative of the capacitance, an output chopper configured to convert the output signal of the capacitance-to-voltage converter to a sensed voltage representative of the capacitance to be sensed, an analog accumulator configured to accumulate sensed voltages during an accumulation period of NA sensing cycles and to provide an accumulated analog value, an amplifier configured to amplify the accumulated analog value, and an analog-to-digital converter configured to convert the amplified accumulated analog value to a digital value representative of the capacitance to be sensed. The analog accumulator may include a low pass filter having a frequency response to filter wideband noise.

Abstract: Capacitance sensing circuits and methods are provided. The capacitance sensing circuit includes a capacitance-to-voltage converter configured to receive a signal from a capacitance to be sensed and to provide an output signal representative of the capacitance, an output chopper configured to convert the output signal of the capacitance-to-voltage converter to a sensed voltage representative of the capacitance to be sensed, an analog accumulator configured to accumulate sensed voltages during an accumulation period of NA sensing cycles and to provide an accumulated analog value, an amplifier configured to amplify the accumulated analog value, and an analog-to-digital converter configured to convert the amplified accumulated analog value to a digital value representative of the capacitance to be sensed. The analog accumulator may include a low pass filter having a frequency response to filter wideband noise.

Abstract: The system provides secure controlled access to multiple Bluetooth devices issued to users. For example an officer may be issued a weapon. To enable monitoring of weapon status, a Bluetooth sensor may be fitted to a holster and the Officer issued with a Bluetooth enabled mobile phone. In order to establish a secure Bluetooth connection between the devices, sensor contains a restored link key and the mobile phone stores a partial link key. The supervisor enters their username and password, and a secret key into the phone which is then used with the partial link key to generate a copy of the link key stored in the first device, so that a secure connection can be established with the first device. The officer enters their username and password into the sensor, and once the secure connection is established it is sent over the secure connection to the mobile phone which then sends both user names and passwords to a verification authority.