Permanent Magnet

I have done a thorough study on permanent magnet and its material. Now, need to start looking for the magnet. I have found out several magnet supplier around Auckland. I need to identify the suitable size of magnet to use in the project.

We have decided to use the Neodymium type of magnet, because the material would have the strongest magnetic field and It is available in the market. We found out that they are not cheap!!, it cost us 40 bucks just for the disc type with diameter of 40mm and 10mm thick.

This is a massively powerful, neodymium "rare earth", disc magnet. The strength rating is N45. Most magnets sold in NZ are N35, which is significantly weaker. Neodymium 
magnets are about 10 times more powerful than normal ferrite magnets.

"Any sufficiently advanced technology is indistinguishable from magic" 

- Arthur C. Clarke