Microwave sensor to replace mechanical arm for sensing tree trunks

[agmech]

I am looking for a sensor that I can mount on a machine, drive along a tree row, and detect only the tree trunks. There are several mechanical devices that do this, but rely on physical contact to actuate a switch. These systems have many drawbacks. I have used commercial microwave door openers in simular applications and they work very well on large canopies. I am looking for something with a narrow beam width (less than 45 degrees) and a very short range (1 to 3 meters). The application is in a harsh environment with lots of dust and spray to contend with. Optical systems do not work very long, and ultrasonics are sensitive to the spray. There is sometimes extraneous vegetation such as grass and woody suckers that I would like to sensor to ignore or not see. The tree trunks would be 4 inches or large in diameter. Any ideas would be appreciated.

 

[nbucska]

Ultrasound proximity sensor ? <nbucska@pcperipherals.com>