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Author Topic: Sensing Distance of People - Ultra Sonic Sensor ?  (Read 1121 times)
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Hello All,

I am currently in the planning stages for a new art Installation. I am posting here for advice and guidance. Specifically I am checking whether anyone has any prior experience that could save me time and help me to avoid going down the wrong route to achieve my aims. I thank you in advance for any help you may offer...

Basically - I need to control the Volume (output level) of an audio oscillator in relation to the proximity of an approaching person (or persons, I'll come back to that) to an object.

The object will be a suspended steel sheet ( 2m x 1m ), hanging vertically, face-on in the centre of a room. The room is yet to be chosen, but lets say its dimensions will be 12m x 12m.

So if the entrance is 6m from the steel sheet, I will need to sense somebody approaching from 6m, and have the volume of my oscillator increase as they get closer to 0m.

It is possible more than 1 person may be in the room with the object at one time. In this instance I would like to take the reading ONLY from the nearest human being to the object.

I have some experience of Pure-data, Arduino and Processing.

My intended approach to this task is as follows:

Ultrasonic sensor SRF-08 connected to arduino
Arduino feeding data to Processing or Pure Data - increasing the Volume of an Audio oscillator ( at a fixed frequency ) as the distance figure falls.

My Questions are:
Firstly, is this the right approach ?
Is Ultra Sonic sensing the best method for this ?
If I use multiple sensors to cover people approaching from more than one side of the object will they interfere with each other ?
Can you foresee any problems ? ( e.g. I have read there may be problems with Ultrasonic sensing and soft clothing?)


Many Thanks for your time, and apologies if I have omitted any necessary info,

Twogan


 
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St. Leonards-on-Sea, E. Sussex, UK.
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I don't think that ultrasonics will work very well for sensing distance with people.
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Leon Heller
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Thanks Leon. Why do you think ultrasonics would not work ? Can anyone suggest a better method ?

Thanks
T
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I never used ultrasonic, but I could imagine it does not work well with people, because it's intended to be used with bigger things like walls for example.
edit: found this
So D would be 10 inch wide beam... should detect a person...

Capacitive sensors came into my mind when I read "steel sheet". Maybe you can use it as the antenna? Here is a little tutorial with the capSense library.

Im not shure how capsensors react to multiple persons, but it would work from any angle and is very cheap!

« Last Edit: February 09, 2011, 06:09:38 am by greenfly » Logged

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Thanks Leon. Why do you think ultrasonics would not work ? Can anyone suggest a better method ?

Thanks
T

People don't reflect sound very well.
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Leon Heller
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Did some experiments with an IR distance sensor the - SHARP 2Y0A02 F 9Y - Its range is 20-150 cm. See my article on the playground - http://arduino.cc/playground/Main/MultiMap

SHARP has other sensors with different ranges: - http://www.acroname.com/robotics/info/articles/sharp/sharp.html - but there are more suppliers for IR sensors.

Hopes this helps,
Rob
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Rob Tillaart

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