Abstract: The present invention provides a simulator which when used aboard a vehicle normally undetectable by a traffic signal control system (e.g. A.C. energized buried sensing loop type which detects predetermined changes in the characteristics of an electromagnetic field due to the presence of a detectable vehicle therewithin), will substantially simulate the characteristics of a detectable vehicle within its field and thereby cause any activation of the system. Operationally, the simulator derives an electrical signal from the field (e.g. via a receiving antenna), converts the electrical signal into a modified transmittable signal of an amplitude which when impressed upon the field (e.g. via a transmitting antenna) simulates electromagnetic influence of a detectable vehicle therewithin which is sensed by the detector circuitry and activates an associated traffic signal controller to provide the necessary signals (e.g. a green arrow) to allow safe and unobstructed traffic flow at an intersection.

Abstract: An apparatus and method for using an output device such as an LED to show the approximate analog level of a variable electrical signal wherein a modulating AC waveform is superimposed either on the signal or a reference voltage, both of which are then fed to a comparator which drives the output device. Said device flashes at a constant perceptible rate with a duty cycle which varies in response to variations in the level of the input signal. The human eye perceives these variations in duty cycle as analogous to variations in the level of the input signal.

Abstract: An improved buoyant alarm device which provides an indication of a disturbance to a quiescent level of a body of water. The device includes a cover assembly and a buoyant body. The cover assembly includes a cover member and a support member. The support member provides a subassembly support for electrical components which are mounted thereto and for forming, with the cover member, an enclosed water-tight chamber for housing the electrical components.

Abstract: A conditions monitor circuit for repetitively displaying the condition of a plurality of sensors which recognize different conditions includes a plurality of gates that are divided into groups which specify conditions for their respective sensors. The gates in each group are connected to a particular sensor and there is a clock for sequentially enabling each group of gates. The enabling clock pulse for each group of gates is also connected to a driver circuit to indicate which sensor is being interrogated. The gates in each group are connected to all of the conditions indicating driver circuits through diodes. There are display means connected to the driver circuits for indicating both the particular sensor being scanned and the condition of that sensor.