On 01/27/2012 10:23 PM, Viesturs Lācis wrote: > 2012/1/28 Rafael Skodlar<ra...@linwin.com>: >> >> Of course that won't work with most if not all the suggestions I've seen >> so far. If I understand it correctly, your "laser" already has a circuit >> to drive it at reasonable current to do it's magic. >> >> Circuit I suggested earlier was under assumption you have a bare laser >> diode connected to it. You cannot daisy chain circuits one after another >> and expect laser to work properly. >> >> Relays are out of question IMO because they are too slow mechanical >> devices with many other drawbacks for this application. I see no reason >> to bring in solid state relays into the picture either. You are not >> driving high voltage stuff. >> >> You either need to modify your PCB that came with the laser diode or >> build a new circuit. Maybe you can reverse engineer that PCB and use one >> spot to inject signal from the EMC side. > > Ed, Kirk, Rafael, thank You! > > Given my lack of skills in electronics, I think that interfering and > modifying the pcb that comes with laser is the last thing I want to > do. > Here are some pics of the laser and its pcb I took late in last night > with my phone (it was late enough that I forgot to upload them > yesterday evening): > http://picpaste.com/2012-01-27_21.54.59-QzJqS24n.jpg > http://picpaste.com/2012-01-27_21.55.16-mx4U2GiU.jpg > http://picpaste.com/2012-01-27_21.55.36-wtANcKHw.jpg > http://picpaste.com/2012-01-27_21.56.28-ySpITI8d.jpg > > I think that I will try the "use a relay" approach, because: > 1) it is simple enough for me to do it; > 2) it does not require modifying existing laser's board; > 3) it will be fast enough for me, because I am going to use the laser > in a "a la milling" fashion - move laser along the line to be burned > instead of moving it back and forth and switching it on, when > necessary, because: > a) the laser is weak, so by definition it can't burn quickly;
That will cause missed or late start unless you compensate that with stepper or servo waiting for the relay/laser delay. Photo sensor in a loop (PID) could fix that but that's more work than creating a simple current limit circuit with LM317 and a few other components as noted earlier. If all else fails, you can burn a T-shirt for yourself :-) http://blog.craftzine.com/archive/2011/07/diana_engs_laser_lace_tops.html > b) machine is heavy and relatively slow, compared to "normal" laser > engravers, so it would not be able to handle very powerful laser > anyway; Not necessarily true. Not knowing how it looks like it's hard to tell. Remember that light can be transmitted over a long distance "around the corners" using mirrors like this one: http://madmodder.net/index.php?topic=4895.0 as long as it's not too foggy. > c) g-code generation - I have no idea, how to generate g-code for > "normal" laser engraving, but I know, how to do it for "a la milling" > style. > > > BTW client was happy, when he saw the first hand-burned lines in the > wood that I managed to do last night in that small moment, when the > laser was working... > > Viesturs more links: http://www.laoslaser.org/ these guys have a roadmap something suggested on this list: http://wiki.laoslaser.org/index.php/Roadmap I hope we see some pictures of the final system. -- Rafael ------------------------------------------------------------------------------ Try before you buy = See our experts in action! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-dev2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
