Abstract: A voltaic pile has first and second terminals by which it is charged and discharged. The pile comprises a plurality of modules (3), each having respective third and fourth terminals with a plurality of voltaic cells connected in series therebetween. The modules are connected series-wise or in series-parallel configuration by the respective third and fourth terminals, with the end terminals of the series of modules defining the previously mentioned first and second terminals. A power supply Load (1) is provided with DC input terminals and AC output terminals, the DC input terminals connected via lines (2) with the first and second terminals. Thus, even in the absence of Power charging current or drain current, the power supply is able to draw upon the output of the pile to supply power back to individual modules that may require charging, to maintain balance among the modules.

Abstract: A controller contains software which, when triggered in some prearranged way such as assertion of an input to the controller, calculates a digital signature for the contents of the protected memory of the controller. The digital signature is preferably extracted from the contents of the memory by means of a function that varies greatly with even small changes to the memory contents. The function preferably is such that one cannot easily determine from the output what input generated the output. The function is preferably such that one cannot easily create a data set for input that yields any particular predetermined output. The circuitry generating the signature may be embedded in hardware of the controller so that its digital signature function is unknown even to the programmer writing the main body of code to be stored in the protected memory. With such a hardware configuration, it is possible to have a very high degree of confidence that the memory contents are what they are expected to be.

Abstract: A signal processing system for a strain-gauge pointing device has a reduced parts count and permits the use of relatively inexpensive low-tolerance components. The system can process signals from two or three or more strain gauges, permitting additional inputs by users without a linear increase in the number of signal processing components. The system employs an RC network to develop an offset for the signal to be provided to an analog-to-digital converter. The system performs each measurement twice, once with a particular excitation polarity and again with the opposite excitation polarity, which permits correction for drift and temperature instability.

Abstract: A clock stretching circuit (110) mites between a synchronous bus (112) and a microcontroller (124) which is asleep most of the time to save electrical power. The bus is of a type in which a slow bus device can cause the sender of data to “hold” the data until the slow device is up to speed. The stretching circuit (110) is of small component count and low power consumption, and there is no requirement for a continuous clock. In one embodiment is comprised of a triple analog switch (120, 121, 122) and a very small number of additional components. In another embodiment a dual four-position multiplexer (162, 163) is employed. In still another embodiment, four transistors (210, 212, 213, 215) are used with handful of additional components. A level shifter (220, 221, 222, 223) including an MOSFET and a large-value resistor help to minimize power drain within the bus device.

Abstract: A signal processing system for a strain-gauge pointing device has a reduced parts count and permits the use of relatively inexpensive low-tolerance components. The system can process signals from two or three or more strain gauges, permitting additional inputs by users without a linear increase in the number of signal processing components. The system employs an RC network to develop an offset for the signal to be provided to an analog-to-digital converter. The system performs each measurement twice, once with a particular excitation polarity and again with the opposite excitation polarity, which permits correction for drift and temperature instability.

Abstract: A signal processing system for a strain-gauge pointing device has a reduced parts count and permits the use of relatively inexpensive low-tolerance components. The system can process signals from two or three or more strain gauges, permitting additional inputs by users without a linear increase in the number of signal processing components. The system employs an RC network to develop an offset for the signal to be provided to an analog-to-digital converter. The system performs each measurement twice, once with a particular excitation polarity and again with the opposite excitation polarity, which permits correction for drift and temperature instability.

Abstract: A controller contains software which, when triggered in some prearranged way such as assertion of an input to the controller, calculates a digital signature for the contents of the protected memory of the controller. The digital signature is preferably extracted from the contents of the memory with a function that varies greatly with even small changes to the memory contents. The function preferably is such that one cannot easily determine from the output what input generated the output. The function is preferably such that one cannot easily create a data set for input that yields any particular predetermined output. The circuitry generating the signature may be embedded in hardware of the controller so that its digital signature function is unknown even to the programmer writing the main body of code to be stored in the protected memory. With such a hardware configuration, it is possible to have a very high degree of confidence that the memory contents are what they are expected to be.

Abstract: An improved energy-saving keyboard with low parts count accomplishes a sophisticated regime of low-power mode intervals in response to key closures and communications from the computer to which the keyboard is connected. An interrupt pin of the keyboard controller (encoder) prompts the transition from low-power mode to normal mode. The communications from the computer is synchronous communications mediated by a clock line, and the interrupt pin is tied not to the clock line but to the data line of the synchronous channel. The interrupt pin is also tied to a resistor array providing pullup biases to the keyboard matrix; in normal-power mode a discrete output of the encoder forces the common point of the resistor array to a fixed voltage level. In low-power mode, on the other hand, the discrete output is not asserted, and the resistor array is pulled high by a pullup impedance of relatively high resistance to the fixed voltage level. In this way, any key closure at the keyboard triggers the interrupt.