In Car Protection for young children

A reader now living in the USA wrote to EPE asking if we had ever published a design for a circuit he had in mind. His idea was for a device that would warn him if his small child had crawled to the rear of the car and into the area of the tailgate.

Children creep into any area that seems interesting to them and this can lead them into danger. A busy parent removing shopping from the car could become distracted and the child could fall out. Probably worse, if he or she should crawl with head, hands or feet partly outside an open door, closing it would cause severe injury.

We had to say that we had not published a design for this purpose. However, it struck the author that this was such a good idea that it would be worth pursuing. The circuit finally chosen and described here uses a passive infra-red solution. The unit is housed in a small plastic box placed so that it can “see” along the line that the child must not cross. If he or she does so, an internal buzzer will sound. The system will operate over a distance of over two meters so it should be suitable for all normal cars.