On 13/07/10 06:11, Oli Glaser wrote: > > -------------------------------------------------- > From: "Olin Lathrop" > Sent: Monday, July 12, 2010 8:19 PM > To: "Microcontroller discussion list - Public." > Subject: Re: [TECH]:: Auto stop table saw - demo with real finger > > >> If the system is cheap enough and >> the cost+hassle of resetting it is minimal, then it will be more widely >> deployed and thereby save more injury than a fancy system nobody installs. >> It also wouldn't give a false sense of security and invite sloppiness like >> SawStop may in some cases. >> >> So maybe the target should be to do what you can for a reasonable cost >> that >> can be reset in one minute or less with no consumables to replace. >> > Yes that sounds like a reasonable target, at least to start with, and if it > achieves better results then it's a bonus. The main reason it occurred to me > in the first place (as I'm sure it occurred to many others) was the cost of > resetting/replacing the SawStop system seems (to me) like it's biggest > problem, and possibly the main reason for people avoiding it (apart from the > fact that it cannot prevent injury completely as a guard if used correctly > will). > Something that works as a good backup system to a proper guard, is > reasonably cheap/simple to manufacture and install, resets quickly with no > extra cost, sounds quite attractive from a consumers point of view and as > you say would be less likely to invite sloppiness etc. > I think it makes sense that such a system would always have to have > something else in place that's non-reliant on a circuit performing it's duty > correctly, so backup rather than main safety feature sounds like a good > idea, especially for the times when people need to remove the guard for some > reason, or do something accidental or stupid. > The field of stopping a rotating metal disk is a fairly thoroughly explored field, they are called car brakes. I'd wager with a hydraulic accumulator, shop air, and some ABS/brake components you could stop the blade near arbitraily fast. damage to the blade would be minimal, though you would want to check it for warping if it got used often. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist