proximity sensor (metal)

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Thread Starter

Anonymous

Hello, New to this website. I wonder if anyone can put me on the right path to find out how to build a metal proximity sensor. I am comparatively new to electronics and understand that these work with occilation (SP?). Is there a shortcut or an easy way to build these? I need many. Thanx for any help.
 
hi, i am from turkey. proximity sensors, there are 2 types, npn and pnp. which one are u using? where u use this sensor? if u sent me more informatiom i can help u. i need details... etc.
 
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Robert Scott

Yes, there is a shortcut. Buy one ready made. There are plenty of vendors. Banner is one.

Robert Scott
Real-Time Specialties
Embedded Systems Consulting
 
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Bouchard, James \[CPCCA\]

There are many manufacturers out there that have spent years and millions of dollars developing the expertise to build proximity sensors. Designing you own is a waste of time unless you plan to build millions of them. Get a Turck, Pepperel + Fuchs, Effector, Balluf etc catalog and select the one you need. If you need a lot ask they for a volume quote.

James Bouchard
 
First of all... I can't answer your question, sorry... but I'm curious, why do You need to build one, there's a lot of very good prox switches "off the shelf"...

Jim
 
Hi, unless you are building one for a project it is much easier and cheaper to purchase proximity switches. The added benefit from the manufactured prox. switches is their ruggedness, which is hard to efficiently duplicate. If you are bent on building one, you can do some research on the eddy current killed oscillator.

I hope this helps.

Kevin
 
Hello, I don't know zip about sensors and am justlearing about circuits. I havent designed one yet. I suppose they use amplifiers because of what you said about pnp npn? What I am using it for is pretty simple: I want to know when a certain mechanical component is in a certain place by detecting the metal and pass that info to a c++ program. Thanx. Scott.
 
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Matthew Hyatt

How many? 10, 1000, 10000000000?

you can buy them from places like
www.newark.com
www.digikey.com

or ask a good local electrical / electronics supplier, they are reasonable cheap and given the time it would take to design, protoype, refine and put into use (production??), you'll have several hundreds (thousands)of dollars invested. can probably buy a good cheap one for 10 or 20 bucks.

MJH
 
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Curt Wuollet

And you check around (Jameco for example), and your needs are simple, you can get them for less than the hardware to make them. But, if you want to learn how they work, I found some pretty good stuff with Google and a few old electronic circuit "treasuries". If the low cost alternatives hadn't showed up, I might be tempted to make them, as the name brands do tend to be a bit spendy however convenient. Some involve large quantities of very fine wire which is hard to handle by hand.

Regards

cww
 
Lot of useful information on here, thank you. I can't affort to buy them and I am genuinely interested in making them or at least understanding how they work. Scott.
 
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I was wanting to make a proximity sensor, so to do this I copied the wheel sensor on our cars ABS (One broke). I pulled apart a small relay and isolated the coil and its iron core, I stuck a small magnet from a mobile phone earpiece to the end of the core. This made the sensor.
I tested the sensor using an iron gear wheel lashed onto an old video motor.

With a 1K load on the coil and the end of the core about 1mm from the gear teeth I got a sinosoidal signal of approx 2V p-p with the teeth passing at a rate of approx 300 per second. This seemed to work quite well.

Although I agree strongly with the chap who said that the biggest problem you will have is rugged mounting and reliability - I intend to drill out a bolt and epoxy the coil inside (I have yet to see what effect this will have on the output)
 
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