Magnetic bush problem in project

[Badea Claudiu]

Hello,

I have a project with a big problem, and seems that nobody can help me and giving me the answer why is it not working.
So, let me explain about the project:
As you can see in the attached picture I have a little device with an inductive snzor, that must detect the presence of the neodim magnet 2 , but, the problem is that I have another magnet neodim magnet 1, that is pressed in the aluminium case. The inductive sensor must cross through that magnetic bush(see the poles mentioned) and when the neodim magnet 2, is in front of the sensor to detect the magnet. I need the bush magnet, because I must attract neodim magnet 2, every time in the same position.
The big problem came here, even if neodim magnet 2 is not in the position, the inductive sensor is getting signal.
I use the sensor from the link bellow:
https://www.mysick.com/eCat.aspx?go=DataSheet&Cat=Row&At=Fa&Cult=English&ProductID=77107
It is NPN and NO.
Can somebody tell me if I will use the sensor from link bellow, will change anything?
https://www.mysick.com/ecat.aspx?go...D=424&Category=Produktfinder&Selections=60074
It is NPN and NC.

I can't use a sensor smaller or bigger than M5 with pitch of 0,5mm because the parts are allready milled and there is no more time untill the project must be finished(Friday 10.04.2015)
Maby somebody know a place from where I can buy another capacitive sensor or optical sensor with this dimensions.

Or maby another idea that can be implementet in this time.

Waiting for a concrete and at object answer because of the short time.

Thanks in advance

 

[KTW]

One method that might work is to shield the sensor from the #1magnet.
It would mean boring out the center of the magnet and placing a shielding bushing or buy a magnet with a larger core and insert the bushing between the sensor and the magnet.
It would be like a protective sleeve around the sensor reducing the magnetic side affect on the sensor.
This is just a suggestion as I've never worked on anything like this.

 

[hevans1944]

If all you want to do is detect when the two magnets are mated together, remove the inductive sensor and replace it with a pin switch. Adjust the switch in and out of the hole until it reliably actuates when the two magnets are in contact with each other.

 

[Badea Claudiu]

Hello,

Thanks all of you for reply.
I found the solution.
The inductive sensor have a detection range of 1,5 mm, I adjusted it untill the magnet bush don't activate it anymore(aprox 10mm from surface) far away from the detection range of the sensor, but when I put the neodim magnet 2, because of the magnetic field, the inductive sensor detect that the second magnet is in position, and here is the problem resolved

Now I have another problem, I have the same problem, with the same assembly idea, but there is an stainless steel pin, that is attracted by the magnet, and the power of holding is not so big because of the stainless steel.
The same magnetic bush with the same sensor.

I couldn't find a capacitive sensor with M5 and 0,5mm pitch, but I found an optical one, here the problem is the delivery time, that is aprox 2 weeks.

I can't use the switch ideea, because there must be a big force to push the switch.

Waiting for your sugestions.

Thanks again everyone.

 

[KTW]

Can you use a nylon pin? Your stainless pin may have impurities in it, a source of pure stainless could be the cure.