A different an interesting arrange for DIY HALL:

http://www.sukhoi.ru/forum/attachment.php?attachmentid=134869&d=1306067091

HDD magnets, that are use not only do excite HALL but to replace gimbal springs, the joystick is centered by magnet force. Gimbal made with HDD parts, include disc.

http://www.sukhoi.ru/forum/showthread.php?t=59583&p=1625474&viewfull=1#post1625474

Sokol1