Using a sensor to sense the presence of copper wire.
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I'm hoping to find a way to insert a bare copper wire thru a hole in an enclosure, then have a sensor that sees the presence of the wire, and the sensor sends out a signal to relay, that sends a signal to a solenoid, that activates a pneumatic cylinder, that will clamp the wire in place.
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Newbie here, attempting to create a fixture that will use a sensor, that will signal when there is the presence of copper wire.
The wire inserted into the area of the sensor will vary from:
36 ga. - 5 ga. Magnet wire
24 ga. - 10 ga. Stranded wire with the insulation removed.Any idea which direction I should go for a sensor?
Thank you, Jay
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Please see attached image:

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@moparjay how about building a simple metal detector circuit like this : https://www.electronicshub.org/metal-detector-circuit
If you stick the wire through the foil it'll probably be able to detect it -
The button you see mounted in the pic, is a momentary (normally closed) switch.
If I can find a sensor to work properly, this will be used to open the spring loaded cylinder manually by the operator "after" the signal is sent to close the cylinder.
If the sensor automation does not work out (to close the cylinder), the button will be to manually open the cylinder that will "always" be in the closed position. Push the button, cylinder opens, wire inserted, release button, cylinder returns to it's normally closed position.
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The plan was to have this contraption automated in the clamping motion. Simply insert wire, sensor sends signal, closes the cylinder to clamp the wire in place.
But if this is too difficult, I'll resort to Plan-B, which is having the cylinder always pressurized in the "clamp" position or "closed" position. Push the momentary, to open the cylinder, insert the wire, release the button, cylinder returns to closed / clamp position.
The photo is only a test piece for experimentation. The REAL unit will be enclosed with a row of many cylinders / contacts / etc., with the ability to hold many different wires at once, all independent from one another.
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@gohan said in Using a sensor to sense the presence of copper wire.:
Given the variety of the wires diameters, I think the 1 or 2 buttons solution is the most reliable one. Just my 2 cents
I agree.
I can accomplish what I want with a single momentary. So, it's no big deal....just hoping to make it more automated.
My original plan was to use a proximity switch. But I quickly learned the issues with consistently detecting copper.
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Please see attached image:

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How about a pressure switch .
If you are referring to a pressure switch for the wire to apply the pressure, the wire will be as small as a human hair. Not capable of applying pressure.
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How about a pressure switch .
If you are referring to a pressure switch for the wire to apply the pressure, the wire will be as small as a human hair. Not capable of applying pressure.
@moparjay
have you thought about using a jfet? -
What about something like this:
https://www.keyence.com/products/sensor/proximity/ta/models/th-305/index.jsp -
@moparjay
have you thought about using a jfet?have you thought about using a jfet?
Thanks for the info. But I'm fine with the simplicity of a momentary, if full-automation-clamping is too difficult...or expensive. LOL
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have you thought about using a jfet?
Thanks for the info. But I'm fine with the simplicity of a momentary, if full-automation-clamping is too difficult...or expensive. LOL
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@moparjay
what about when sliding the wire into the top hole you give it a + charge and the base a - charge with a circuit that will do when the 2 touch.what about when sliding the wire into the top hole you give it a + charge and the base a - charge with a circuit that will do when the 2 touch.
If the range of wire size was tighter, this would probably work well. But with the wide range of sizes, trying to make contact with the smallest sizes would be a real pain.
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what about when sliding the wire into the top hole you give it a + charge and the base a - charge with a circuit that will do when the 2 touch.
If the range of wire size was tighter, this would probably work well. But with the wide range of sizes, trying to make contact with the smallest sizes would be a real pain.
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Optical detection: a light source on one side of the hole and a phototransistor on the other, read as analog values since the small wires won't completely cover the light source
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Inductive sensor, a coil around the hole, and some form of detecting the change of inductance, start by making a small coil and test with a LCR meter
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Capacitive sensor, open air dielectric, plates across the hole, the wire and operator (even holding the insulated wire) will change the capacitor response a lot, test with some capacitive/touch sensing circuitry.
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Thanks to all that have given input. I'm going to give in and simply use the momentary to open the cylinder (normally closed). It's just too easy. And going automated is not worth the added expense, as this single cylinder prototype will be duplicated to almost (100) cylinders....each completely independent from one another. Thank you!!!