Abstract: An illuminated keyboard includes a light-emitting diode light string, a controller, a feedback line and a plurality of keys. The light-emitting diode light string includes a plurality of light-emitting diode modules which are connected in series through a serial connection wire. Each light-emitting diode module includes a light-emitting diode chip and a drive circuit. The controller is electrically connected with the light-emitting diode light string. The feedback line is electrically connected between the light-emitting diode modules and the controller. The keys correspond to the light-emitting diode modules and are electrically connected with the feedback line. Each light-emitting diode module emits light according to a received light-emitting signal and outputs a feedback signal. When at least one of the keys is switched to a pressing state, the feedback signal is pulled from a first level to a second level for the controller to differentiate the key in the pressing state.

Abstract: The invention provides a control method for sets of series-parallel-connected LEDs via a single wire. Step 1: providing an LED circuit including a control module and a light-emitting module. The light-emitting module includes LED strings connected to one another in parallel. Each of the LED strings includes a plurality of LED units connected in series to one another, and at least one counter comprising a counter start time different from that of another. Step 2: sending a setting signal by the control module, and allocating one identification code obtained sequentially in time to one of the LED string according to the different counter start times of the LED strings. Step 3: sending a designation signal to the light-emitting module by the control module, such that the LED string with the corresponding identification value is selected and independently controlled by the control module.

Abstract: The present invention provides a capacitive sensing circuit, comprising at least one capacitor to be measured, an integral capacitor, a first current mirror having a first current path and a second current path. A first current is generated in the first current path so as to charge the capacitor to be measured, while a second current mirrored from the first current is generated in the second current path so as to charge the integral capacitor. As such, the mirrored current, resulted from mirroring the charging current on the capacitor to be measured, is used to charge the integral capacitor. Charge energy charged on the capacitor to be measured may be copied onto the integral capacitor so as to reflect a voltage signal. Subsequently, capacitance variation generated when the capacitor to be measured is touched may be sensed by detecting the voltage signal.

Abstract: An electronic circuit for calculating image shift in successive images generated by using image invariant optical speckle patterns, with results output as serial I2C or A/B phase signals. The device comprises a laser LED light source, an optical structure, an image detector, an integrated circuit, and a micro-controller. The laser LED light source generates a collimated laser directed at a contact surface through the optical structure. The image detector may capture the speckle patterns from a moving surface. The integrated circuit can perform image shift calculations to determine the shifted distance moved on the surface so as to output the serial I2C or A/B phase signals, which the micro-controller can utilize for movement and location determining applications. Because it is capable of measuring extremely fine changes on scales of one micrometer or less, this invention may be used in surface recognition and precision control applications.