#robotics Logs

Feb 11 2015

04:36 deshipu LiohAu_: at random
04:36 LiohAu_ ?
05:13 deshipu LiohAu_: your question lacks context and therefore is impossible to answer properly
05:14 LiohAu_ ok, I want to build a robotics base with 4 mecanum wheels
05:14 LiohAu_ the wheel diameter is 4 inch
05:15 LiohAu_ and the manufacturer indicates that 6mm, ... to 16 mm hubs are compatible
05:16 LiohAu_ but I don't know what criteria determine which hub I should choose
05:16 LiohAu_ Actually I don't even know to what the "6 mm" (or 16) refer. Is it the motor shaft ?
05:18 deshipu I suppose that's a question you should direct to the manufacturer
05:24 SquirrelCZECH nah
05:24 SquirrelCZECH can't get that mesh center alg. right
07:18 SquirrelCZECH nah
07:18 SquirrelCZECH folks
07:19 SquirrelCZECH do you think there is some nice way how to calculate weight of 3d printed part?
07:19 SquirrelCZECH :)
07:19 SquirrelCZECH except for slicing it
07:19 SquirrelCZECH and let's say I am able to claculate weight for any 3d object defined with triangles
07:22 SquirrelCZECH I suppose most bullet proof way is to slic3 it, make stl from that gcode and calc. weight for that stl
07:35 joga if you know how long a piece of filament went into it, should be easy to calculate
07:36 Triffid_Hunter SquirrelCZECH: yep, slic3r even spits out the filament length at the end of the file for you
07:47 SquirrelCZECH Triffid_Hunter: yeah
07:47 SquirrelCZECH but center of mass will be more interesting :)
08:46 deshipu SquirrelCZECH: I just always use the geometric center of the robot's body
08:46 deshipu SquirrelCZECH: most of the time you want them to coincide anyways
08:47 SquirrelCZECH yeah but now I can calc the "real one"
08:47 SquirrelCZECH only constraints is that the mesh should be "homoghenic" ? or how is proper term for 100% one material?
20:58 rue_more SquirrelCZECH, take the length given to you when you load it in pronterface and multiply it by the fil size to get plastic volume / weight
21:49 RifRaf rue_more: http://i.imgur.com/z0rXSbV.jpg
21:51 katsmeow-afk what is it?
21:53 ace4016 a rubber band maker :P
21:55 RifRaf rainbow extrusion
21:56 Tom_itx yours?
21:56 RifRaf yep
21:56 Tom_itx what extruder is that?
21:56 RifRaf testing new triplestruder, gonna make a kit for it
21:57 RifRaf its my triplestruder
21:58 tsmeow-afk ponders monogrammed p
21:59 RifRaf alphabet soup?
22:03 rue_more hmm
22:03 rue_more RifRaf, was it uspposed to be something?
22:03 RifRaf yes
22:04 RifRaf a filament swapping test. no point printing till it reliable
22:04 rue_more ah
22:04 rue_more shoudl I be concerned about the splits in the gears?
22:05 Tom_itx i'd think so
22:05 Jak_o_Shadows bloody cold end jammed
22:05 rue_more cold end?
22:05 RifRaf nope
22:05 Jak_o_Shadows the bit of the extruder that doesn't heat up.
22:05 rue_more printing water?
22:05 RifRaf seems to be something with the clear abs
22:05 rue_more oh
22:06 Jak_o_Shadows also, I have now realised why people don't swap the way
22:06 Jak_o_Shadows the x axis
22:06 rue_more swap?
22:06 Jak_o_Shadows invert the x axis
22:06 rue_more ah
22:06 rue_more RifRaf, why not put it to use making ornaments while you test?
22:16 RifRaf rue_more: cause there are no designs
22:16 RifRaf have to make em, so rather make extruder, get it in the wild, then designs will be made by others :)
22:17 RifRaf will make up a few test objects though, maybe a vase tonight
22:19 RifRaf rue_more: that was its first test though, about 200 changes without issue
22:33 blib is there a program somewhere, which takes triplets - speed/time taken/distance traveled and turns that into an equation (that relates the quantities)?
22:44 Triffid_Hunter blib: sounds like basic calculus, should be all over wikipedia and a thousand math sites
22:45 Triffid_Hunter I mean, speed = distance / time, seems fairly simple.. it's even described as distance/time eg meters per second or kilometers per hour
22:51 blib Triffid_Hunter: speed = distance/time -> has that equation ever worked for you for a real robot (and real measurements)?
22:51 Triffid_Hunter blib: do you understand how math works? speed is literally defined as distance / time, how could it ever not work?
22:52 Triffid_Hunter you can measure the distance wrong, or measure the time wrong and thus get a wrong result, but measurement issues don't mean the math is broken