With some modern, streamlined cars with large boots and also convertibles and vans, it is difficult to judge the dimensions when sitting in the drivers seat. Acoustic parking assistants can make things easier. These inform the driver, through sound intervals, about how much space there is between the vehicle and possible obstacles or pedestrians, they also serve to protect the precious bodywork from being damaged. In certain cars, cameras can be had as an optional extra, indeed, not only as a parking aid. Not only can the driver see the space directly behind the vehicle, he can also keep an eye on the load or on the tyre pressure of a trailer. Recently, cameras are being installed right up front in the vehicle, to see, e.g,. when passing through a narrow gateway, the sidewalks on both sides as early as possible.
Three, four or even five proximity sensors send out ultra sonic signals to the obstacle and calculate, through the time it takes untill the reflexion is returned again, how much space remains. The result of these calculations is sent to a control device, which goes into operation when the reverse gear is engaged. It initializes the whole system and causes the sound module to emit a short beep-tone. This indicates that the system is intact, not like a control-light which goes out (e.g., ABS) but a signal-tone. Should there be no sound when the reverse gear is engaged, a disturbance in the system is indicated. The closer one gets to an obstacle, between 160- and 20 cm, the shorter the intervals between the beeps are. A continuous tone is a warning, it means that contact is about to occur. Because the control device is also capable of comparing the signals from the individual sensors, the exact distance to an obstacle which lies between two sensors, can be calculated. Large obstacles are also recognized. In this case, for as long as the distance remains constant, the continuous tone can be switched off after a certain period. The system works largely independent from other systems, thus it can also be fitted as an extra (e.g., from Conrad Electronics). Even the laying of the cable through the entire vehicle to the gearbox can be avoided by a short connection to the reverse lamps. There are similar systems for the front-end of vehicles. In the development departments, work is being done on the possibility of electronic-coupling (e.g., trucks), using this or similar technology. In the long term, at least in the middle- and particularly in the luxury class vehicles, with a sufficiently large display, these systems will be complemented or substituted, because the picture from a camera can be scanned and certain images can be examined. In standard vehicles the pictures, although four at one time, can only be shown on the display up front. Thereby, the (wireless-) connection makes it possible to use up to 16 cameras at the same time. The driver's-seat is transformed into a directors chair! 11/11