Abstract: An allergen particle detecting apparatus has a sample area through which environmental air is directed. A light beam is directed through the air sample so that portions of the beam will be scattered if any particles are present in the path of the beam. A beam blocking device on the opposite side of the air sample is arranged to block all light except light scattered in a predetermined angular range corresponding to a predetermined allergen particle size range. Light transmitted through the blocking device is detected by a light detector and an alarm output signal is produced if the detected amount of light is above a predetermined level.

Abstract: An automatic monitoring and recharging system adapted to continuously monitor the terminal voltage of a D.C. storage battery and, whenever the terminal voltage falls below a first preselected value, to automatically initiate an engine-driven A.C. generator which is utilized to recharge the storage battery. The recharging interval is terminated when the recharging current attains a second preselected value whereupon the system is automatically returned to a voltage monitoring status.The monitoring and recharging system of the present invention finds particular utility with respect to storage batteries used in association with recreational vehicles.