PING sensor to measure altitude?

parts-man73

Say I had a flying RC vehicle, such as a Plane or Helicopter. Could a Ping sensor be mounted to the bottom, pointed straight downward, be used to measure the altitude? (up to the distance limit of the PING Sensor)

My thoughts are, that as the ultrasonic burst is transmitted, the vehicle has moved forward by time the reflection returns to the sensor. Or is there an better sensor to use in this type of application?

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Brian

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Mike Green

Theoretically you could use a PING up to its distance limit. The returned sound pulse radiates in all directions from any object that reflects it and an RC plane or helicopter isn't moving that quickly compared to the speed of sound.

Practically, you need to consider how uniform and "hard" the surface is to the sound waves. You want a good, solid reflection from only one surface to get quality distance measurements and, unless you're flying a helicopter or really small and slow plane in, say, a gymnasium with a hard wooden floor, you'll get sloppy distance measurements.

Phil Pilgrim (PhiPi)

Another consideration is ambient noise. A powered RC plane will be producing a lot of it, and it may interfere with any ultrasonic echoes the Ping))) is expecting, resulting in false readings. I tried installing an ultrasonic sensor on a fruit-sorting machine once to measure the heights of apples passing underneath. But the clanking of the conveyor chain and sprockets, along with other ambient factory noises, rendered it almost useless.

My only recommendation would be to try it and see if it works. You may have to take more than one reading and use the best two out of three, for example, to filter out the noise. Be sure to report back, so others can benefit from your experience.

-Phil