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Metal Detector using hall effect sensor

Former Member

Hi,

 

I want to build a metal detector through a hall effect sensor. This detector will be a rectangular tube design hollow from inside and multiple hall effect sensors will be arranged along the length of the tube in the inner walls. Now when a metal object passes through the tube, theses sensors should be able to tell about it. The whole idea is to utilize the variations in the earth's magnetic field inside the tube when metal object passes through and sensors will pick up this little variation to detect metal.

 

Now, I know this could be difficult with hall effect sensor. The variation in the earth's magnetic field will be too little for the sensor to detect it. However, there could be some way of getting this done. One way could be to magnetize the path inside the rectangular tube, so a passing by metal object gets magnetized and induce greater variations in the field.

 

Could you recommend some other possibilities of doing this. Some solution, that will give very reliable detection, zero false alarm and better range of detection so that the size of rectangular tube could be actually increased, making this design practical ?

 

I would look forward to the suggestions of you guys. Kindly reply

 

Thanks

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    Time is a fairly easy quantity to measure with electronics.  So, if we can translate our param of interest into something that modulates an oscillator, we may be on our way to a cheap and reliable system.  I suggest you google something like "What's all this V/F (or F/V) stuff anyhow" for more on this timelessly exciting technique.

     

    Perhaps, you could wrap a coil of magnet wire around a plastic tube through which your stuff flows.  You could make an oscillator with this inductor as a timing element.  Ferrous stuff passing through the tube would make the coil seem larger electrically, slowing down the oscillator.

     

    Ti has a circuit sorta like this that they use for turning springs into scales.  Maybe you could adapt it.

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  • 0

    Time is a fairly easy quantity to measure with electronics.  So, if we can translate our param of interest into something that modulates an oscillator, we may be on our way to a cheap and reliable system.  I suggest you google something like "What's all this V/F (or F/V) stuff anyhow" for more on this timelessly exciting technique.

     

    Perhaps, you could wrap a coil of magnet wire around a plastic tube through which your stuff flows.  You could make an oscillator with this inductor as a timing element.  Ferrous stuff passing through the tube would make the coil seem larger electrically, slowing down the oscillator.

     

    Ti has a circuit sorta like this that they use for turning springs into scales.  Maybe you could adapt it.

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