I used the plugin that is almost the same that tweakie used, but it was adapted by Kazuki.
It is incredible, he manged to make it useful even in usb new boards,
I used high power magnets with a lever construction with a really strngth coil ,but with a pull movment, so i could achieve a high speed response.
I also used a step motor circuit to power the coil of the magnet, and i used a voltage regulator to dose the strength of the impact.I bought 10 diamond tips from china by 20 dollars,very cheap,and after making more than 20 granites , it is still useable,and i have 9 more to use,very cheap, i guess it is cheaper than laser.
And it really impacts the granite, or steel or glass.
Pls be free to ask question, but I advise you...it a make and mistake until you get there.