Hi guys, sorry to "revive" this thread, but I would like to know if somebody has been able to control this kind of spindle (outrunner with an ER collet) with an Arduino UNO to be able to achieve precise RPMs? As this would make it much more practical for the kind of use I want to make out of it... if so, how did you achieve it? Would it bother you sending the line of codes / diagram / pictures / videos or anything else to show what you did and all that? I am a newb when it comes down to electronics and really want to achieve this ! Thanks !!