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What sensor should I use to sense the distance of an unknown object? Answered


I'm trying to put together a project for the first time with an arduino uno board.

The aim of my project is to sense the distance/position/proximity of ANY object away from my sensor (board). Ideally, I want a system that is able to give good reading if the system is operating out-doors. The entire system is housed inside a box with only the power line coming out of it. The cost of the system should be cheap enough for a small, hobby project. The range of the sensor should be about 2cm to 3m.

I've looked at IR, ultrasound, and hall-effect sensors. They're not really what I need because
1. IR sensor doesn't work well out-doors
2. Ultrasound sensor has to be exposed outside of a container to send out the sound waves.
3. Hall-effect sensor needs the object being detected to have a magnet attached to it.

So are there other options I can go with?? A different kind of magnetic sensor where if the magnetic field it produced was disrupted by an unknown object, the sensor can give me back a distance reading of that object?

8 Replies

rickharrisBest Answer (author)2012-07-08

+1 If you have rejected the obvious.

You don't specify the range you need to work at but:

IR works quite well outdoors especially if you encode the signal. your Tv remote works pretty well doesn't it? try it out doors you won't find a lot of change.

US need not be fragile - many cars have US reversing sensors these days the system works well up to about 7 or 8 mtrs.

magnetics only work with metallic objects.


Pressure sensors
Capacitive proximity detectors

You can look these up easily.

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petergeng28 (author)rickharris2012-07-09

I think radar is something i could look into.

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petergeng28 (author)rickharris2012-07-08

My range is around 2cm to 3m.

Well the IR work fine if it had to be placed inside like a box? does that interfere with the signal?

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steveastrouk (author)rickharris2012-07-09

Glass, or perspex ? One of them blocks IR from LEDs.

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steveastrouk (author)2012-07-08

Capacitance can be made to work over several metres - in WWII it was used as a method of measuring aircraft height, with great accuracy, up to about 6000 feet.

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