Abstract: The present invention provides a radio frequency (“RF”) activation system with improved operating capability and ease of installation. Improved responsiveness is provided by the receiver which determines the frame timing of incoming signals and calculates the estimated time of arrival for ensuing frames thus minimizing loss of frame synchronization problems. In one embodiment, this is accomplished by determining the time span of the frame start sequence and using this to determine the frame timing of an incoming RF signal. The receiver also makes corrections for timing errors between the receiver and transmitter by re-synchronizing the receiver with the incoming RF signal.

Abstract: A control system (80-1, 80-2) is provided for a grain dryer (10) having a path (22, 24) along which grain is conveyed from an entry opening (28) between first (12, 14) and second (18, 20) walls provided with second openings through which drying air can flow. A source (16) on the side of the first wall opposite the grain provides a flow of air through the first wall, through the grain and through the second wall to dry the grain. The grain dryer (10) further comprises metering rolls (30, 32) between the walls (12, 18, 14, 20) adjacent the end opposite the entry opening (28) to control the movement of the grain along the path (22, 24). The control system includes a first moisture probe (80-1) positioned remote from the metering rolls (30, 32), a second moisture probe (80-2) positioned adjacent the metering rolls (30, 32), and a microcomputer (150).

Abstract: A battery charger has battery terminals connected to a conventional wall outlet through a switching power supply to provide a direct conductive non-isolated path from the supply for direct transformer-less supply of charging current to a battery. Pulse width modulated signals are applied to a MOSFET of the power supply from an output port of a microprocessor which is operates a ramp generator and responds to a comparator circuit coupled to a battery voltage sense circuit and the ramp generator. The microprocessor is programmed to accurately control generation of the pulse width modulated signals, to shut off current when a true voltage peak is reached at a full charge condition, to avoid response to false peaks, to cut off current for short time intervals during voltage measurements, to perform an exponential averaging function and to shut down at excessive battery temperatures or time rates of change of battery temperature.

Abstract: The invention comprises a method for operating a door hold-open device and a device for carrying out the method. A door hold-open device which unlatches a held door based upon the occurrence of an unlatch condition includes a door latching mechanism, a signal processing circuit having a power source. The method consists of the steps preventing the signal processing mechanism from consuming electrical current, upon occurrence of an unlatch condition, generating a unlatch condition signal and providing electrical current to the signal processing mechanism to power it, determining the continued existence of the unlatch condition signal with the signal processing mechanism and upon determination of the continued existence of the unlatch condition signal with the signal processing mechanism, transmitting an electrical unlatch signal to the door latching mechanism.

Abstract: A battering charging system is controlled by a microprocessor to charge and discharge batteries while periodically effecting monitoring and control operations in which battery current data are registered to accumulate capacity data in a memory and to thereafter display such data which includes both charge and discharge capacity data. The system has different modes of operation which may be selected by a user, including a charge mode, a discharge mode and an autocycle mode. In the autocycle mode, efficiency rate data is computed and displayed.

Abstract: A battery charger system is provided in which a microprocessor is used to discontinue application of a high charge current when the battery voltage drops below a peak value by a value greater than a threshold value corresponding to stored digital data. The microprocessor is also used to obtain a discharge mode of operation and an autocycle mode of operation in which a charge operation is performed after a discharge operation, the microprocessor being responsive to actuation of keys of a keyboard. In performing various operations, the microprocessor is used in performing analog-to-digital conversions and it is additionally used in computing energy capacity and efficiency.