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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?


+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.

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?

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.

Tape measure.