# Motion sensors



## CTshockhazard (Aug 28, 2009)

Would an inductive proximity sensor work?


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## mutabi (Jun 2, 2009)

I wonder if a speed sensor would work. They only turn on if they are made and broken a certain number of times every minute/second. For example it looks at the speed of a fan, and if the fan speed drops below a certain rpm (whatever the sensor was designed for), the sensor drops out. I imagine they would sell them with all sorts of pickup "speeds". So simply making the prox is not good enough. 

Or use a PLC with a regular sensor with some creative programming. 

Just brainstorming  Someone else may have the perfect solution


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## InControl (Mar 20, 2007)

I don't know of a motion sensor that will dectect movement of metal. But, an analog prox _may_ do what you need. Depending on your application and the uniformity of the metal, it might be possible.

More specific questions get more specific answers :detective:


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## MDShunk (Jan 7, 2007)

Crap, I wish I could remember what this thing was called that we used at AMP all the time for that situation. It worked on RF, somehow. The metal was between two antenna "whiskers". Once you had it dialed in, it would just switch a set of C-NO-NC contacts if the metal moved. It worked on brass, bronze, aluminum, steel, stainless, copper, and pretty much anything else made out of metal. That description might ring a bell for someone.


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## bustedbulb (Jan 8, 2010)

*Photoelectric Sensor*

Photoelectric sensors represent perhaps the largest variety of problem solving choices in the industrial sensor market. Today ’s photoelectric technology has advanced to the point where it is common to find a sensor that will detect a target less than 1 mm in diameter while other units have a sensing range up to 60 m. These factors make them extremely adaptable in an endless array of applications. Although many configurations are available including laser-based and fiber optic sensors, all photoelectric sensors consist of a few of basic components. Each contains an emitter, which is a light source such as an LED (light emitting diode) or laser diode, a photodiode or phototransistor receiver to detect the light source, as well as the supporting electronics designed to amplify the signal relayed from the receiver.


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## Denk (Jan 9, 2010)

To MD Shunk this sounds good if yourself or anybody else can help here would be much appricated


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## Hunter1151 (Nov 4, 2010)

Denk said:


> I am trying to find a motion sensor that will dectect movement of metal, but there is a catch. I need it to dectect only if the metal moves.If the metal is stationery in the line of the sensor the sensor remains passive. This will be used in a industrial situation 24volt dc would be nice


Look at eatons iprox they are programmable to fit your application


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## etb (Sep 8, 2010)

Maybe you are looking for an eddy current sensor. They are similar to a prox but would have the capability to detect motion, not just presence. Depending on the mfr & your interface they can also do distance, thickness, velocity, ...

MD's description does sound like it would be based on RF so perhaps you could google that as a starting point.

PS Eddy current sensors work for all conductive things, not just ferromagnetic metals; this may help or hurt depending on your setup.



InControl said:


> More specific questions get more specific answers


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## Sawdust454 (Sep 26, 2008)

Check out Banner products,
http://www.bannerengineering.com/en-US/products/8/Sensors/44/Vehicle-Detection

The items on this link will do what you want.


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