Abstract: A method and apparatus for synchronizing a series of interconnected alarm devices. The alarm device detecting an alarm condition produces a signal having a distinct rising edge which is detected at each of the remaining alarm devices. A pulsed alarm signal having a fixed number of pulses is generated at each remaining device in response to the rising edge. A reset signal from the alarm device detecting the alarm condition resets each of the remaining alarm devices after each fixed number of pulses is produced so that each of said devices has a pulsed alarm signal which begins and ends at substantially the same time.

Abstract: A method and apparatus for synchronizing a series of interconnected alarm devices. The alarm device detecting an alarm condition produces a signal having a distinct rising edge which is detected at each of the remaining alarm devices. A pulsed alarm signal having a fixed number of pulses is generated at each of said remaining devices in response to the rising edge. A reset signal from the alarm device detecting the alarm condition resets each of the remaining alarm devices after each fixed number of pulses is produced so that each of said devices has a pulsed alarm signal which begins and ends at substantially the same time.

Abstract: In a processor controlled, battery operated dangerous condition warning device employing a DC-to-DC converter, the converter selectively operates at two voltage outputs. A first output voltage is used when a sensor is polled and when audio visual devices, such as LEDs and a horn, are driven; i.e., when higher power is momentarily required; at all other times, a second, lower voltage output, sufficient for ongoing operation of the processor as it keeps time and processes information, is issued by the converter. In a presently preferred embodiment, when the processor determines that the higher voltage is momentarily required, it sends a first signal to a transistor switch to change the voltage at a reference input to the converter which responds by issuing the higher voltage. When the higher voltage is no longer needed, the processor sends a second signal to change the state of the transistor switch such that the converter reverts to the lower output voltage, thus decreasing the load on the battery.