The static magnetic field needle search is a simple and reliable needle search in apparel industry . Especially it was widely used in Japan, China and South East Asia. But it is only inspect the ferromagnetic metal, it does not inspect aluminium ,copper and stainless steel etc.
Fortunately all needle is ferromagnetic.
This project is its control system.The hardware is based in STM32, the software is based in uCOS II. But I'm sorry, it does not finished.