Ultrasonic Alarm (1)

I will introduce the alarm equipment which arranged "Ultrasonic Range Meter" on these pages.
This alarm equipment transmits a ultrasonic and receives the ultrasonic which is reflected at the obstacle and gives the alarm in the case which set within the distance. The distance which can be set is from about 40 cm to 10 m. For example, when setting to the 5 m distance, it doesn't detect a reflection from more than 5 m distance. However, the alarm can be given when there is a reflected wave from among from 40 cm to 5 m.
By "Infrared Sensor" to be introducing in another page, it can detect only the object to be in the movement while emitting infrared rays. However, in case of this ultrasonic alarm equipment, the object is OK even if it has stood still. Also, it is OK even if it isn't emitting the infrared rays. But, it is necessary to be the object which reflects the ultrasonic.

I made the maximum detection distance with the alarm signal about 10 m. However, it becomes difficult to receive the reflected wave from the obstacle at the receiver when becoming long-range. The detection probability becomes bad.

It had better limit to the short distance use.