The Blind Zone – Understanding the Principles of Operation

When an application calls for an Ultrasonic sensor it is very important to understand the principles of operation. The most important question in sensor selection… what is the operating distance needed? How far away can I be from the target? Understating “The Blind Zone” will be the key to selecting the proper sensor for your application.

“The Blind Zone” is the shortest permissible sensing range. This means that no objects or targets are permitted within the minimum working area (“Blind Zone”) as this would false trigger the sensor. For example we have an application where we need to see our target at 80mm away. We could select a sensor that has an operating distance of 20….150mm. This means we can see our target down to a minimum distance of 20mm and a maximum range of 150mm. anything below the 20mm is the “Blind Zone” and out of our working range of 20…150mm.

The shortest permissible sensing range
This is determined by the blind zone of a sensor. No objects or are permitted within the blind zone, since this would cause faulty measurements or readings.


So as you can see it is very important to understand your minimum working area and where the “Blind Zone” begins within the working range of the senor. If you have any questions on this topic or other questions on Ultrasonic sensor selection, please leave a comment below.

2 Replies to “The Blind Zone – Understanding the Principles of Operation”

  1. Hi, I’m currently working on a project where we need to measure distance and ultrasound is one of the methods we’re looking at. However we must be able to measure short distances as well. As far as I understand the blind zone is made due to the sensor having to switch between transmit and receive mode (please correct me if I’m wrong). We were wondering then if it would be possible to eliminate this blind zone with a separate transmitter and receiver module. Could you please indicate if this is correct.

    Thanks in advance

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