#qi-hardware IRC log for Sunday, 2014-01-26

whitequarkwpwrak: 3mm metric00:03
whitequarkI've measured it with a caliper00:04
DocScrutinizer05((USB is not realtime, hence, in order to make an USB CNC, you need...)) still doubting that quite a lot00:15
whitequarkDocScrutinizer05: well, there's some isochronous shit00:15
whitequarkbut it's not easy00:15
whitequarkwpwrak: okay, read the stuff you wrote00:16
wpwrakyou don't want to send real-time commands. just load a set of instructions and process them. if the pc stops unexpectedly, just bring the mill to a halt00:16
whitequarkI think I want an adjustable collet00:16
DocScrutinizer05I think wpwrak and me discussed it and I evaluated the maximum speed you can drive it00:16
DocScrutinizer05and the maximum precision you can achieve (due to 'jitter' of USB) which you anyway only want to use in low speed mode00:17
DocScrutinizer05it's always oust one max one step error00:17
wpwrakyou could get away with it but why take chances ? much easier to   cat stuff.gcode >/dev/ttyUSB0  and be done with it00:18
DocScrutinizer05and one (micro)step of steper should always be quite below what's max precision of your CNC00:18
wpwrakelse you also have to worry about other usb peripherals getting in the way, your process not getting scheduled in time, and all that00:19
DocScrutinizer05errr, doesn't exactly same problem apply for realtime LPT?00:19
wpwrakof course. that's why you need a dedicated pc for it :)00:20
wpwrakif you put it all into the usb critter you can use your laptop00:20
DocScrutinizer05and I still say that's nonsense00:20
wpwrakwell, what happens if you miss a deadline ?00:21
wpwraka general-purpose pc will sometimes do that, especially if your application involves usb.00:21
DocScrutinizer05the max jitter mustn't exceed 50% of step time. IOW you mustn't have >+/-180° phase jitter00:22
wpwrak(without usb you can have a separate real-time subsystem that will be relatively safe. but it can only talk "best effort" to the rest of the system)00:22
DocScrutinizer05max step freq of any such stepper is well below say 5kHz00:23
wpwrakwhat happens if you get the timing wrong ?00:23
DocScrutinizer05how wrong?00:23
wpwraklet's assume you can detect it and take corrective actions00:23
DocScrutinizer05completely missing a step?00:23
wpwrakwrong = let's say something prevents you from running for 10 ms00:23
wpwrakor 100 ms. or whatever00:24
wpwrakthink of a usb bus reset00:24
whitequarkwpwrak: DocScrutinizer05: EMC2 uses linux-rt kernel00:24
whitequarkyou'd need a linux-rt kernel even for usb one00:24
DocScrutinizer05as long as you sync in with next or 2nd next step to a hard pace raster, nothing will happen. Motor is too slow (aka inert) to do anything bad with one or two wrong steps00:24
whitequarkunless you offload the movement completely to the controller00:25
whitequarkand then it basically needs a gcode interpreter00:25
DocScrutinizer05sorry, that's nonsense00:25
DocScrutinizer05you can run rt processes in any arbitrary standard linux00:25
wpwrakwhitequark: i think the gcode interpreter sounds like the way to go. find the subset you actually need.00:25
whitequarkwhy does linux-rt kernel exist then?00:25
wpwrakDocScrutinizer05: but they're not really RT ;-)00:25
whitequarkwpwrak: simple subset of gcode can be implemented very quickly00:26
DocScrutinizer05they are sufficiently RT for a low number of processes or even just one process00:26
whitequarka more interesting one which would be compatible with EMC2 is a tad more work, you'd need shit like expressions00:26
whitequarkbut it is not really hard00:26
wpwrakwhitequark: two different things. regular linux "rt" is high scheduling priority. but disabling interrupts or anything that doens't want to give up its time slice will still delay you00:26
whitequarkDocScrutinizer05: ^00:26
DocScrutinizer05when you take care to have a driver in kernel to watch for the timing00:26
wpwrakwhitequark: the special rt kernels have a special subsystem that has complete priority over the regular kernel00:26
whitequarkand EMC2 really runs on the border of possible jitter for my mill00:27
DocScrutinizer05says who?00:27
wpwrakwhitequark: you probably don't need all the bells and whistles from the beginning. and since you have the code, you can just compile it as a checker with which you can dry-run the jobs, see if there's anything you couldn't handle.00:28
whitequarkwpwrak: of course00:28
whitequarkor just upload it to device and let it verify00:28
whitequarkI'd want a higher-end F4 anyway for floating point00:28
whitequarkthat'll make NURBS splines and so very easy00:28
wpwrakwhitequark: yup. once you're confident, that's the way to go. have a nice big led to tell you when something it missing. or add a little OLED ;-)00:29
wpwrakif you get an F4 then an OLED would be fitting :)00:29
DocScrutinizer05honestly guys, you sound like you know something about software but pretty much zilch about stepper motors00:29
wpwrakDocScrutinizer05: yes, but we know the sw rather well ;-) if a complex io subsystem linux usb is involved, things get messy. now i didn't try to do rt with usb but i did with ide. and while you can get very good results, you won't always win.00:31
DocScrutinizer05of course when you think you can create a 1second metronome like "while true; do beep; sleep 1; done" then you get into trouble with stepper motors and persumed non RT properties of linux00:32
whitequarkit's not a problem to run linux-rt today anyway00:32
whitequarkdebian has it00:32
DocScrutinizer05look, amiga1000 did "realtime stepper motor" all the time, for floppy head positioning00:33
whitequarkDocScrutinizer05: well, it essentially had an RTOS then00:33
whitequarklinux is way more complex00:33
DocScrutinizer05yeah, you for sure will fail when you think you can control your LPT or USB from a norma userland process directly00:34
DocScrutinizer05no matter what scheduling you use00:34
DocScrutinizer05toldya you need a kernel land module that runs with kernel prio to do the realtime stuff00:35
wpwrakin fact user space is just fine as long as you request a real-time priority00:36
wpwrakfor example, this is in user space: http://downloads.qi-hardware.com/people/werner/ubb/vga/web/00:36
DocScrutinizer05GTA02 OS did FIQ for HDQ and for vibra PWM iirc. And each one worked fine as long as not both happened same time00:37
whitequarksure, but is the USB stack itself realtime? I betcha it's not00:37
wpwrak(of course, ubb-vga does a great many ugly things ... ;-)00:37
wpwrakof course it isn't00:38
DocScrutinizer05now tell me that a 1GHz x86 ca't do what a S3C2442 with err 200MHz(?) been able to accomplish?00:38
wpwrakand usb is easily upset00:38
whitequarkit can, with linux-rt00:38
wpwrakjust plug in a usb device that has problems and boom00:38
DocScrutinizer05heck, "the USB stack" is not even working for flashing00:38
DocScrutinizer05I guess what you cal "the USB stack" does a lot in userland00:40
whitequarknot in userland but in kernel threadlets00:40
wpwrakbesides, whitequark will need something to fill that monstrous f4 with. so there's every reason to have the gcode interpreter in there ;-)00:40
wpwrakdoes USB use tasklets ? i never looked00:41
whitequarkI remember it had00:42
DocScrutinizer05err yep, worker thread or whatever, I seem to recall from musb_hdrc00:42
whitequark[khubd] ?00:42
DocScrutinizer05worker thread is "user land" for me, though really it probably isn't00:42
wpwrakyeah, worker threads in the kernel are pretty much like user space, as far a scheduling is concerned00:43
DocScrutinizer05that's what I thought, though i never looked into it00:43
DocScrutinizer05it's their purpose00:43
wpwraknote that they can therefore also get "real-time" priority. but just be careful with that ...00:43
wpwrak(waits for larsc to chime to in ;-)00:44
DocScrutinizer05oh SHITE. Looked out the window and noticed the world got mouldy since I last did00:47
DocScrutinizer05I like mildew only on cheese00:48
DocScrutinizer05and some special sorts of salami00:48
wpwrakyour disconnected fridge has windows ?00:49
DocScrutinizer05and it's laaaarge00:49
DocScrutinizer05they actually built my apartment inside that fridge00:49
whitequark(I think acid's kicking in)00:51
whitequarkDocScrutinizer05 --> http://25.media.tumblr.com/vVmbDWseNi0vony2V6inpGjoo1_400.jpg00:51
DocScrutinizer05lol, check out Kafka, do you think he needed any chemicals?00:52
DocScrutinizer05actually, I dunno. Did he?00:53
wpwrakdid anyone in that era not ?00:54
whitequarkI think he was legitimately crazy00:54
whitequarkwhich is the same thing00:54
Action: whitequark <3 Kafka00:54
wpwraki don't. way too close to reality.00:55
DocScrutinizer05http://de.wikipedia.org/wiki/Die_Verwandlung  hmmmm00:56
DocScrutinizer05well, my mildew is pretty close to reality then00:57
whitequarkThe Castle is amazing00:58
whitequarkI've read it while doing a certain paperwork-intensive process00:58
DocScrutinizer05and I think pondering about what's "home2 and "freedom" for a bird that never lands is not any weirder than http://de.wikipedia.org/wiki/Der_Bau00:58
whitequarkit's like wanting to kill yourself, but now also in your fantasies00:58
whitequarkmagic smoke HAS escaped from the spindle board.02:11
whitequarksome guy from forums reported the same thing02:15
whitequarkso it's likely not me02:15
whitequarkthe transformer is HOT02:17
whitequarkI can't touch it, it's that hot02:17
whitequarkaha, I'm inclined to think that the transformer was breakdown02:21
whitequarkthe spindle started to spin very quickly on a minimal setting, then there was some cracking noise and a funny smell02:21
whitequarkexcept it's not the smell of exploded semiconductors, it's more the smell of fresh epoxy02:22
whitequarkand a fuse is burned02:22
whitequarkI'd say electrical breakdown of insulation in the transformer. guess it wasn't rated for 136V after all.02:22
whitequarkoh, and there's nothing visibly burned or exploded or just hot on the spindle board.02:23
whitequarkah, no, there's a dead 781202:27
whitequarkINPUT shorted to GND... a very lucky mode of failure. burned the fuse and probably saved the rest of circuits02:29
DocScrutinizer05yes. but it's hard to believe this been caused by a mere 20% "over"voltage02:37
whitequarksure. as I've said, some guy on the forums reported this board exploding, too, I've googled it by the board markings02:38
whitequarkalthough in my case, if the 7812 exploded, it's certainly a big overvoltage02:38
whitequarkI guess I can try to turn it on without load and measure the actual AC output of the transformer02:38
DocScrutinizer057812 is hardened for for input voltages up to 30V iirc, and should shut down on overtemp. And a transformer hardly ever breaks from overvoltage02:38
whitequarklet's hope it doesn't burn my house down or something... reminds me I need to get a fire extinguisher02:38
whitequarkthere's a smoke alarm, but afaik it's not even plugged in, much less working02:39
whitequarkrussia, duh.02:39
DocScrutinizer05when transformer is of abysmal quality, it might short a turn in primary coil (out of no particular reason), which in turn causes a short and massive temperature increase due to that, which shorts further turns in primary, reducing the number of active turns on primary, thus turning a e.g. 20:1 transformer into a 1:1 transformer02:41
whitequarkin this case, will the transformer itself tend to burn down when I use it?02:42
DocScrutinizer05I'd claim warranty repair at seller/manuf, clearly stating that you probed the input voltage with DVM and it been in allowable range for a 110V device02:43
DocScrutinizer05transformers have nothing that burns02:43
whitequarkI mean literally, in a fire02:43
DocScrutinizer05they can get pretty hot02:43
DocScrutinizer05but can't burn02:43
DocScrutinizer05(except the very huge ones)02:43
whitequarkoh okay. guess I'll just be quick then02:44
DocScrutinizer05well, eventually isolation will evaporate and maybe create flamable fumes02:44
DocScrutinizer05at maybe 300°C02:44
DocScrutinizer05usually *every* transfomer is built in a way so it "fuses" out before anything like this ever happens02:45
DocScrutinizer05also all transformer devices madatory have a real fuse in primary circuit02:46
whitequarkit's connected directly to the mains02:46
DocScrutinizer05which should blow as soon as a single turn in transformer shorts02:46
whitequarkwell, through a switch02:47
DocScrutinizer05sometimes swirch has builtin fuse02:47
whitequarkdoesn't seem like such a switch02:47
DocScrutinizer05often transformer has builtin fuse02:47
whitequarkwell, maybe02:47
whitequarkactually, hm, zero voltage on output02:47
DocScrutinizer05often chinese build incredibly dangerous crap and still aren't shy to print "CE" on it02:47
whitequarkeither a fuse or just some of my plugs are shitty (they are)02:48
whitequarkwell, the *rest* of the device is built very well. good looking PCBs, nonshitty components, good soldering, all wires are accurately wrapped in cambric with the name of circuit printed02:49
DocScrutinizer05like this: http://maemo.cloud-7.de/share-service/20121122_001.jpg02:49
whitequarkcomponents are from the official vendors (ir, nec, toshiba japan, etc) and not chinese generics02:49
whitequarkyeah, that's sad02:49
DocScrutinizer05the above is prone to kill you with 220V when the 0.05mm plastc fail to isolate the PCB thruhole solderpoints from the Alu heatsink02:50
whitequarkokay, I'm pretty positive the transformer is dead02:51
whitequarkthe autotransformer is buzzing like crazy when I plug the device in02:51
whitequarkit never did before and looking as the load is disconnected entirely... yeah02:51
DocScrutinizer05then you better don't02:52
whitequarkyeah, DOA.02:52
DocScrutinizer05a pity. ask for 50% refund02:52
DocScrutinizer05get good transformer and new 781202:52
whitequarkI wonder if I need a good transformer, I've R/Ed the circuit mostly02:53
whitequarkit's absurdly simple. has 18V~ and 36V~ inputs02:53
DocScrutinizer05sure you can go for any arbitrary 12V PSU given it's strong enough02:53
whitequarkfeeds 18V~ to 7812 and then there's a PWM made with a single 555 timer (no joke)02:54
DocScrutinizer05ooh, what for are the 36V~?02:54
whitequarker, 18V rectified02:54
DocScrutinizer05sure, told ya02:54
DocScrutinizer05that's usualy meant to be 16V~02:54
whitequarkthe 555 output is fed directly to an IRF740 power transistor gating the 36V rectified to the spindle02:54
DocScrutinizer05for you it been 2002:55
DocScrutinizer057812 should cope with that02:55
DocScrutinizer05aaah spindle02:55
DocScrutinizer05yeah, ok. No problem to replace that shit with something homemade02:55
whitequarkokay, tell me... 36V~ is what Vrms or Vp-p?02:56
whitequarkand what does my DVM measure?02:56
DocScrutinizer05what did you use to meter it?02:56
whitequarkit's written on the transformer labe02:56
DocScrutinizer05aaah, it's written "36V" there?02:56
whitequarkyes, and on the PCB too02:56
DocScrutinizer05then it's effective02:56
whitequarkso Vrms right?02:56
DocScrutinizer05err, basically02:57
whitequarkand when I rectify and filter 18V~rms, I get what, 18V= ?02:57
DocScrutinizer05well, what your DVM shows02:57
whitequarkwell, slightly less. assume an ideal rectifier02:57
DocScrutinizer05nah, you get 18V*sqrt(2) iirc02:57
whitequarkbut Vrms is what power I'd get if I plug that into a resistor02:58
DocScrutinizer05unless you have sufficient load02:58
whitequarkso if I rectify it and plug it to the same resistor, I should get same power02:58
whitequarkah, that's what you mean by sufficient load02:58
DocScrutinizer05yes, unless you have a buffer C02:58
whitequarkthere's a huge-ass cap, of course02:58
whitequark2200µF 50V02:59
DocScrutinizer05then it's more like 22V=02:59
whitequarkah I see02:59
whitequarkthat explains why the input on the spindle board is marked 24V03:00
DocScrutinizer05maybe even 2503:00
whitequarkconnected to rectifier output03:00
whitequarkok, so I need a 24V/50V power source03:00
DocScrutinizer05err, the 36V are rectified and buffered?03:00
whitequarkyep, the spindle is a DC motor03:01
DocScrutinizer05the latter particularly03:01
whitequarkyep, there are two smaller caps03:01
DocScrutinizer05you said that's what type of 3-pin transistor?03:01
DocScrutinizer05is it a transistor?03:01
whitequarkpower mosfet03:01
DocScrutinizer05yeah, makes sense03:02
DocScrutinizer05honestly, i'd probably buold it in a similar way03:02
DocScrutinizer05ne555 is just fine for a PWM03:02
whitequarkyeah, it's not a terribly designed board. just the fucking transformer *shakes fist*03:02
DocScrutinizer05do you have a good 24V power source03:03
whitequarkmy adjustable source can give 24V 3A03:03
whitequarkshould be more than enough for steppers... but not spindle03:04
DocScrutinizer05you could try the rest of board and spindle motor with any arbitrary ooops 12V source03:04
whitequarkspindle is 200W so 4A03:04
wpwrakDocScrutinizer05: (transformers have nothing that burns) rememeber that ICE fire ? ;-)03:04
DocScrutinizer05wpwrak: that been alu03:04
whitequarkwpwrak: he said "except really big ones"03:04
DocScrutinizer05that too03:04
whitequarkand those are likely quite big. well, surely bigger than mine03:04
wpwrakah, then you said "(except the very huge ones)". good :)03:04
DocScrutinizer05big ones are oil cooled03:05
DocScrutinizer05big ones are notorious to catch fire03:05
wpwrakwhitequark: (official vendors) how can you tell ? ;-)03:06
whitequarkwpwrak: properly looking laser engraving03:06
DocScrutinizer05whitequark: you can operate spindle with 12V, just to see if it all still works03:06
whitequarkplus usually if they're going to install counterfeit components, the rest of it is going to look like shit03:06
DocScrutinizer05don't turn it up to full power03:07
whitequarkDocScrutinizer05: or 24V03:07
DocScrutinizer05err the 7812 is meant to provide 12V}, no?03:07
whitequark7812 is just for the 555+irf72003:08
DocScrutinizer05sure you can attach 24V to the 36V~ branch03:08
whitequarkso yeah... actually I think I even have a spare 781203:08
whitequarkso could fix it right now03:08
DocScrutinizer05:nod: even better03:08
DocScrutinizer05how's the steppers operated?03:08
whitequarkseparate board. didn't look at it close yet, lemme unscrew it03:09
DocScrutinizer05I'm worried about your report of "sppindle shortly running at full speed on lowspeed setting"03:10
whitequarkyeah, same03:10
wpwrakDocScrutinizer05: (alu) the reports sounds as if before that came the oil from the transformers. but i guess it was all a jumbled mess ;-)03:10
DocScrutinizer05might be caused by 12V branch going offline, leaving the MOSFET at always-closed03:10
DocScrutinizer05wpwrak: yes, that's why I mentioned the oil03:11
DocScrutinizer05use of oil starts at maybe 10kW transformers03:11
DocScrutinizer05maybe even higher03:12
whitequarkok... toshiba tb6560ahq stepper drivers03:12
DocScrutinizer05I guess the motors are powered by 36V as well?03:12
whitequarka lot of what looks like optocouplers, but can't quickly google the part#03:12
whitequarka 74HC chip, and something that looks like a high-power linear voltage regulator03:13
wpwrak(counterfeit) don't count on it. sharism once got a nice patch of some fairly trivial chips. they were ordered as originals and looked credible enough. yet they were fakes. of course they only found out after making a batch of milkymist with them ...03:13
whitequarkno, that board only has one 24VDC input03:13
DocScrutinizer05yes, those definitely are optocouplers03:13
DocScrutinizer05ok, those steppers are not as powerful03:13
whitequarkit's not a linear regulator03:14
whitequarkit's diodes inc AP1501, 150KHz,3A PWM BUCK DC/DC CONVERTER03:14
wpwrakthere you are !03:14
whitequarklemme look the output V03:14
whitequarkwpwrak: that's not enough of them!03:15
whitequarkok... it steps down to 5V03:15
whitequarkthe fuck it needs 24V input for?!03:15
wpwrakin the end you may be able to just use a pc power supply ;-)03:15
whitequarkyes, I'm getting that feeling03:15
DocScrutinizer0524V since it been there03:16
DocScrutinizer05the motors need it03:17
whitequarklemme check where it gets the motor voltage03:17
wpwrakuse -12 V and +12 V ;-)03:17
whitequarkwpwrak: PC PSUs have negligible current on -12V03:17
DocScrutinizer05if it was 110V, the'd have used a SPSU with 110V input03:17
whitequarkalso this mosfet is connected in a way which requires a common ground... it doesn't have an isolated gate03:18
whitequarkso no luck with that scheme. but nice try03:18
wpwrakwell, if you make -12 V your ground and -5 V your "+5 V", you're kinda almost there ;-)03:19
DocScrutinizer05ooh, you mean because of PC PSU ground?03:19
whitequarkDocScrutinizer05: well, it's the gate-source voltage which turns it on03:19
whitequarkif the source is at -12V and the gate is at +12V...03:19
whitequarkactually, it's out of AMR03:19
DocScrutinizer05don't worry, what's PSU ground doesn't have to be steppercontrol GND03:19
whitequarkwhich is 20V03:19
DocScrutinizer05you might use 2 pcs 12V PC PSU in series03:20
whitequarkDocScrutinizer05: anyway, PC PSUs can supply like 300mA on -12V03:20
whitequarktwo PSUs would work, yes03:20
whitequarkit's kind of a shitty setup though03:20
whitequarkand doesn't give 50V too03:20
DocScrutinizer05make sure to power then both up properly before connecting secondary load03:20
whitequarkand I don't have two of them03:21
whitequarkand I can just use 24V output from my configurable supply03:21
DocScrutinizer05yes, I'd try that03:21
wpwrakwhat do the 50 V get mangled into ?03:22
DocScrutinizer05should even work for spindle, at low RPM03:22
whitequarkso... I think I should check whether the stepper board is dead first03:22
DocScrutinizer05spindle motor03:22
whitequarkwith configurable PSU03:22
whitequarkDocScrutinizer05: (refund) it would be hard to argue that 134V is within operating conditions03:23
whitequarksince the block is clearly labeled as 110V-120VAC03:23
DocScrutinizer05I wouldn't argue about that with them03:23
whitequarkah, gotcha03:23
whitequarkthat transformer is so massive, we're talking for an hour and it's still hot03:24
whitequarksuch a waste of metal03:24
whitequarkI could probably sell it for good $03:24
wpwrakwell, it took it about 2 ? 3 ? hours to overheat ...03:24
whitequarkno, I played with it for about 20 minutes this session03:25
DocScrutinizer05when it actually *over*heated then you'd see that from outside03:25
whitequarkand a few hours before that, but it got time to cool down03:25
wpwrakah. so you russians got a bit more careful after chernobyl :)03:26
DocScrutinizer05and that particular usage pattern makes it *very* unlikely it overheated in 20min, after working 3h before03:26
whitequarknever was this joke more appropriate03:26
wpwrakDocScrutinizer05: okay ... became the dominant heating element in whitequark's vicinity :)03:26
whitequarkooooh, THAT's why the room was so hot03:27
whitequarkthat actually may make perfect sense03:27
DocScrutinizer05[2014-01-25 20:53:43] <DocScrutinizer05> occasional manual control of temperature of whole thing can't hurt, until you got familiar with it03:27
whitequark(I'm not serious about the room, it was just the A/C heating it up. But it might have contribued to the problem)03:28
whitequark(manual control) I did control it, without disassembling the block. the metallic case was a bit warm.03:28
whitequarksince metal is a good heat conductor I decided the insides aren't particularly hotter03:28
DocScrutinizer05then it's highly unlikely it overheated03:29
DocScrutinizer05you usually also smell overheated trafo an hour before it becomes critical03:29
whitequarkthe metal transformer core is screwed to a metal pad which is screwed directly to the metal case with high contact area03:29
whitequarkah, no, there was definitely no smell, even seconds before breakdown03:30
whitequarkand I smelled it very strongly immediately after03:30
whitequarkso... what was it if not overheat?03:30
DocScrutinizer05crappy isolation of winding wire03:30
DocScrutinizer05the isolation should withstand the 5 times overvolatge at least before breakdown03:31
wpwrakvolatile components considered unnecessary unless proven otherwise ?03:31
whitequarkwpwrak: volatile?03:31
wpwrakstuff that escapes. under certain acceptable (unless proven otherwise) operating conditions :)03:32
DocScrutinizer05when they used cheap wire to do the transformer coils, and that cheap wire then gets mechanical damage during sloppy manufacturing, then the isolation may break while manufacturing and finally breaks down shorting one wind03:33
DocScrutinizer05or a few winds03:33
whitequarkbtw I can't get off the clamp of the transformer input wire off the terminal03:33
whitequarkit's the same type of terminal like e.g. 12V terminals in cars03:34
DocScrutinizer05often the contact wires are soldered to the thinner internal coil wide, and often those solder joints are sharp 03:34
whitequarkdo they have some hidden latches or something? no amount of forces disconnects it03:34
wpwrakwhat does it look like ?03:34
DocScrutinizer05yes, they have a latch03:34
whitequarklike this one: http://i571.photobucket.com/albums/ss160/4listing/BE_tem1/AU004-tem1-1.jpg03:35
DocScrutinizer05in the center03:35
whitequarkexcept it's on the power socket, like mains socket on a computer PSU03:35
DocScrutinizer05either a bumb that fits into hole, or even a real latch03:35
DocScrutinizer05usually bump though, that goes into the hole03:36
whitequarkah, I see it now. a bump.03:36
DocScrutinizer05apply force03:36
whitequarkalready applying it, with a makeshift lever out of hex key03:36
whitequarkseems like the connector would break first03:36
whitequarkaha, got it off03:37
whitequarkneeded more force03:37
whitequarkhmm, I could fit a small computer PSU in place of that enormous chunk of metal...03:38
whitequarkmaybe two03:38
DocScrutinizer05pro tip: the other side of the hole in the male end is usually open03:39
DocScrutinizer05a smal nail...03:39
whitequark... in the head of whoever made that transformer...03:39
DocScrutinizer05also those plugs always are with two almost closed "tubes", each long side one. You can insert a nail into the "tube" and slightly bend it open. Plug falls off like a dead fly from the wall03:41
whitequarkyep, that was my second option03:41
whitequarkok, in steady state it draws 4mA@24V and the LED on the board is glowing03:43
DocScrutinizer05ok, I got a shiny new camera. Let's see how it performs03:43
whitequarkwait, why exactly is there a LED in a completely black case?03:43
DocScrutinizer05just for you ;-)03:43
wpwrakit's the flashlight. now look for the camera.03:44
whitequarkok, with steppers connected the board tries to draw more than 2.5A of current without connected LPT03:48
whitequarkI guess this means it's fucked too.03:48
wpwrakwhat would be normal peak current ?03:50
DocScrutinizer05wpwrak: hey, that's darkest night: http://maemo.cloud-7.de/share-service/DSCF0137.JPG03:50
DocScrutinizer05well, as dark as it gets at night in a town, with cloudy sky03:50
whitequarkactually no, that was just some initialization or something, idk03:51
whitequarkit actually works03:51
whitequarkand I verified I can use my PSU to drive all three steppers at full speed03:51
wpwrakDocScrutinizer05: neat. lemme check the exif ...03:51
whitequarkit even has some current left, about 1A03:51
DocScrutinizer05good :-)03:52
wpwrakkewl. 1/2 of the problems solved03:52
wpwrakDocScrutinizer05: only 800 ISO, it says. maybe try to get a little higher. e.g., 3200. see how grainy it gets.03:53
DocScrutinizer05auto mode, I just pointed and shot03:55
wpwrakyeah, it says so :)03:56
wpwrakexcept that you may have manually selected "Night scene". or maybe it figured that out on its own as well :)03:56
DocScrutinizer05yes, auto mode03:57
wpwrakit's a bit grainy, which is surprising for only 800 ISO. has a very nice "painting" effect on the branches, though03:58
DocScrutinizer05it's a nice proof of the anti-shake03:58
DocScrutinizer051/8.5s "from the hip"03:59
DocScrutinizer05the orangy WB is actually kinda correct, it looks even more orange than in the photo, thanks to Na-lamps04:01
DocScrutinizer05same scene as seen by N900: http://maemo.cloud-7.de/share-service/20140126_002.jpg04:07
wpwrakah yes, there's a bit of a difference now ;-)04:08
DocScrutinizer05I think yes there is :-)04:09
whitequarkokay, no 7812's04:10
whitequarkbut I have an LM31704:10
DocScrutinizer05hmm, should work too, with correcz circuit04:10
DocScrutinizer05take care about note E in http://www.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=lm317&fileType=pdf04:13
wpwrakalas, i don't have any buildings with nice trees next door. but here's a view of the city: http://downloads.qi-hardware.com/people/werner/tmp/IMG_3253.JPG and then zooming into the lit area with the trees, some 100 m away: http://downloads.qi-hardware.com/people/werner/tmp/IMG_3257.JPG04:14
wpwrakfirst was with the camera sitting on a my monitor and with delayed shutter release. for the second i held the camera but used the monitor as support. exposure 1 second, a bit too long for my unsteady hands.04:15
wpwrakhmm. for night mode, i would have to get out a tripod. too much wind :-(04:21
wpwrakbeside the motion blur, it does look pretty good, though: http://downloads.qi-hardware.com/people/werner/tmp/IMG_3259.JPG04:24
wpwrakshould dial down the brightness a bit. that shop window in the middle looks like a gate to hell04:25
whitequarkok, figured out the lm317 circuit, now to think of a way to put it on the pcb...04:48
whitequarknone of the legs of lm317 are compatible with 7812's :(04:48
whitequarkwell, nothing that couldn't be fixed with some good ol' wirewrapping05:04
whitequark... wow05:12
whitequarkit's been 3 hours since I last used the board05:12
whitequarkI've handled it for at least a hour, probed it, replaced a component on it05:12
whitequarkscrewed it back05:12
whitequarknow I plug in the fuse and the LED on the daughterboard lights up, meaning that enormous 2200µF cap still had some charge05:13
whitequarkI almost shat some bricks the moment I've seen it05:13
whitequarkcertainly wasn't expecting it.05:13
whitequarkanyway. it's assembled back and ready to be tested...05:13
whitequark555 doesn't appear to generate any waveforms05:22
whitequarkbut maybe my DVM simply cannot measure them05:22
whitequarkK1 is the socket for the 05:46
whitequark"spindle on" key05:46
whitequarkD3 leads directly from unfiltered Vsource (bypassing 7812) to NE555's !RESET input05:46
whitequarkI don't know why the fuck is it done that way, but the result is that NE555's likely fried05:47
whitequarkfortunately it is not exactly a rare ic05:47
whitequarkalso I would be very glad if someone explained me how the contraption of C7 C8 D1 D2 Pr1 works05:48
whitequarkPr1 is a potentiometer, marked RED BLACK YELLOW05:49
whitequark(from pin 1)05:49
whitequarkDocScrutinizer05: ok, put 25VDC on both input sockets. the SPINdle does not SPIN at all.05:52
whitequarkand with this motivating discovery I'm off to bed05:52
whitequarkactually no, I'm off to buy NE555 and 7812 and THEN I'm off to bed06:05
DocScrutinizer05well, let's hope the mosfet is ok06:06
whitequarkright, might also want to buy a spare mosfet06:06
whitequarkit's not going to drive me broke06:06
whitequarkthose mosfets are usually unkillable though06:07
whitequarkwow, russian clones of 7812 ( 1428) are still sold06:09
whitequarkI've been told that MTBF of those in field is ~1 month06:09
DocScrutinizer05did you probe the voltage on  that ne555?06:09
whitequarkand they fail by shorting input to ground06:09
whitequarkand imagine what that makes with an AA battery in a tight enclosure... yeah06:09
whitequark(voltage on ne555) it doesn't have anything on the output06:10
whitequarkappears to be floating06:10
DocScrutinizer05I meant VCC06:10
whitequarkor do you mean input voltage from my makeshift 7812?06:10
whitequarkit's 10.6V06:10
whitequarkwell within operating range06:10
DocScrutinizer05ne555 has OC out, no?06:10
whitequarkdoesn't appear so06:11
whitequarkit's push-pull06:11
DocScrutinizer05have you tried shorting the D-S of mosfet?06:13
whitequarkmm, no06:13
whitequarklemme try06:13
whitequarkthe spindle switches on and eats 1A@25V to 27V06:15
whitequarkI mean, it eats 1A in that range of voltages and just spins faster when voltage is higher.06:16
DocScrutinizer05sounds about correct06:16
whitequarkit's rated 200W though... so should eat 4A@50V?06:16
DocScrutinizer05what is DW1?06:19
DocScrutinizer05errr, with load yes06:19
whitequarkDW1? where?06:19
DocScrutinizer05on mosfet gate06:20
DocScrutinizer05next to C306:20
whitequarka glass diode-looking thing06:20
whitequarkwill try to read markings now06:21
whitequarkI mean, it has the same package as 1N4148 http://www.egyptuino.com/store/images/detailed/1/signal_diode.jpg06:21
whitequarkdunno what exactly it is yet06:21
whitequarkSTmicro something147406:22
DocScrutinizer05prolly it *is* a 1N414806:22
DocScrutinizer05that other thing realy is a 10R?06:23
DocScrutinizer05maybe nit's a Zener then06:23
whitequarkcolor coding on other thing doesn't make sense06:25
whitequarkbrown black black silver brown06:25
whitequarkit's either 1©1% or 180©1%06:26
whitequarkdepending on the order06:26
DocScrutinizer05you're talking about the thing at ne555 output?06:27
whitequarkblue body cylindrical resistor06:27
DocScrutinizer05according to layout/componentplacement it's 10R06:27
whitequarkyeah, guess that is incorrect06:28
whitequarklemme measure it, actually. mosfet is as good as floating06:28
DocScrutinizer05brown black black, solver06:28
whitequarkbut the color coding doesn't match06:29
DocScrutinizer05nuke the right brown06:29
whitequarksomething I'm not aware of? weird encoding scheme?06:29
DocScrutinizer05nah, maybe 1W06:29
whitequarkthe body looks like 1/4W06:30
DocScrutinizer05this stuff is not +really* standardized06:30
DocScrutinizer05could even be a coil/choke :-o06:30
whitequarkno, it's marked R206:31
DocScrutinizer05what the heck is this huge blob next to the powerswitch?06:31
whitequarkright down from K1? yes, it's for the steppers daughterboard06:32
DocScrutinizer05I still wonder how that shite works06:35
DocScrutinizer05what's the PWM in/output for?06:35
whitequarkyou can set SW1 to left/right with a jumper06:35
whitequarklike on PC motherboards06:35
whitequarkit's set to "down", next to Pr106:35
whitequarkI suppose this selects the potentiometer controlled mod06:35
DocScrutinizer05ooh I see06:36
whitequarkif you set it to "up" it would I guess get the PWM06:36
DocScrutinizer05via optocoupler06:36
whitequarkand on the stepper board there's actually an unpopulated PWM output06:36
whitequarkDocScrutinizer05: I'm horrified to think what happens if you assert STOP06:38
whitequarkmy bet: EL817 explodes06:38
whitequarkit's rated at 60mA cont, 1A peak06:39
DocScrutinizer05a relais?06:39
whitequarkoh, relay06:40
DocScrutinizer05I think EL817 must also be some sort of optocoupler or relais06:40
whitequarkno. it's an optocoupler. BC817 with a LED pointing at base06:40
DocScrutinizer05it looks like it operates on spindle running or overloeded06:41
DocScrutinizer05R3/R4 = 1R?06:41
DocScrutinizer05then it will prolly start on 4A06:42
whitequarkno no06:42
whitequarkah you're right06:42
DocScrutinizer05so it signals overload06:42
whitequarkI thought it was plugged in reverse direction06:42
whitequarkthat makes sense06:43
whitequarkalso not connected to anything :]06:43
DocScrutinizer05sure, when PWN NC then STOP NC too06:43
whitequarkokay. can you explain how the contraption around Rp1 works?06:45
whitequarkI have absolutely no idea06:45
DocScrutinizer05err yeah06:46
DocScrutinizer05that's the R that defines how fast the C of NE55 charges and discharges. Funny enough the split charge and discharge on both sides of same poti06:47
DocScrutinizer05so the longer it's "on" the shorter it's "off"06:48
DocScrutinizer05D1 and D2 must be "antiparallel"06:48
whitequarkthey are06:48
DocScrutinizer05C is charging via D1 and discharging via D206:48
whitequarkooooo, I understand06:49
whitequarkso it's basically changing duty cycle with two diodes, one cap, one pot and one ne55506:49
whitequarkthat's cool06:49
whitequarkwithout changing freq that is06:49
whitequarkreally clever06:49
DocScrutinizer05and PWM abuses NE555 as a schmitt trigger basically06:52
DocScrutinizer05I'm lost WTF D3 is doing06:54
DocScrutinizer05flyback diode for 781206:54
DocScrutinizer05ok, eaten it06:56
DocScrutinizer05C8 is the freq06:57
whitequarkmhm, can't seem to easily find dual 24V/48V power supply in .RU07:07
whitequarkcertainly not at these currents07:07
whitequarkDocScrutinizer05: how hard it is, would you think, to make a mains 24V/48V switchmode supply myself?07:08
whitequarkI don't really want another 3kg shitty transformer there which is likely to burn just as well!07:08
DocScrutinizer05I recommend to NOT try that07:08
whitequarkyou think so?07:09
DocScrutinizer05building SPSU is no witchcraft but annoyingly tricky07:09
whitequarkwell, I've built several. but for lower voltages.07:10
DocScrutinizer05starts with transformer and doesn't end at low-ESR Cs07:11
whitequarkokay, bad idea, I agree07:11
whitequarkhow about this: make a 48V->24V buck converter and use a single 48V off the shelf supply?07:12
whitequarkor just buy it07:12
DocScrutinizer05how about using two 24V off-the-shelf supplies07:12
whitequarktoo much shit to bother about07:13
whitequarkreally don't like this as a permanent solution07:13
DocScrutinizer05what's the problem?07:13
whitequarkneed to carry two supplies, remember to plug them both in before enabling the device07:14
DocScrutinizer05nah, they fit in where the transformer been07:14
whitequarktwo? unlikely07:14
whitequarkwell, maybe07:15
whitequarkdo you have a specific PSU in mind?07:15
DocScrutinizer05laptop PSU?07:15
whitequarkwon't fit for sure. also, expensive07:15
whitequarkalso, not enough current, those I've seen were under 100W07:16
whitequarkand spindle alone needs 200W... steppers eat about 50W07:16
DocScrutinizer05Iseem to have seen them up to 3.5A07:16
whitequarkwith what voltage?07:16
DocScrutinizer05well, I have no particular PSU in mind. not really07:17
whitequarklet's say I don't know where or which PSU to get to satisfy my constraints07:17
whitequarknever seen anything that'd fit07:17
whitequarkalso, 250W @ 48V = 5.2A07:18
DocScrutinizer05alibaba probably right place to search for that kind of stuff07:18
DocScrutinizer05wait, aren't truck batteries 24V?07:19
DocScrutinizer05when the batteries are 24V, so are the chargers07:21
whitequarkstill need stepup to 48V07:21
whitequarkand for 200W what I can find is $100+07:21
whitequarkokay, I kinda can see why they used the transformer now...07:24
whitequarkremember, spindle needs 4A @ 48V07:25
whitequarkthought of scooter/bike chargers already07:26
whitequarknone have such enormous batteries07:26
whitequarkok, this actually looks not bad: http://www.ebay.com/itm/Logosol-LS-1148-Motion-Control-Device-DC-Power-Supply-48V-11A-24V-2-5A-600VA-/131101846353?pt=BI_Control_Systems_PLCs&hash=item1e86476b5107:27
whitequarkhm, unknown whether it works or not07:27
whitequark"Functionality/Degree of Testing: Unit powers on and indicates EMG. We do not have the necessary resources to further test this unit. Power cable is not included."07:27
whitequarkdo you not have a damn multimeter07:27
whitequarknot bad07:29
whitequarkbut, what about the battery charging circuit?07:29
DocScrutinizer05I doubt is has much of a charging unit07:31
DocScrutinizer05but dunno for sure07:31
whitequarkthat's pretty nice07:35
DocScrutinizer05used and heavy07:41
whitequarkthe previous one wouldn't also fit into the case07:42
whitequarkwell, not that much of a problem07:42
whitequarkyep, looks about right07:50
DocScrutinizer05WTF? http://www.ebay.com/itm/111044654415 LED monster07:50
whitequark510 leds07:50
DocScrutinizer05err sure. 10bucks, shipping 50 bucks07:53
whitequark$47 to here07:53
whitequarkI can route it through US actually07:53
whitequarkwould be $807:53
whitequarkokay. let's first wait and see what the CNC vendor responds07:54
whitequarkif they just send me a new control block, awesome. otherwise I'm telling that this one burned07:55
wpwrakwhitequark: you mentioned that someone else had the same problem. did he mention whether/how he solved it ?12:05
apeletehello there12:31
apeleteI'm looking for a new soldering iron to replace a cheap 30W model I bought off ebay12:34
apeletesomething with a fine tip, to be used for electronic parts, I'm thinking about a 60W model maybe12:36
apeleteany advice ?12:36
wpwrakapelete: you should consider one with adjustable power. there are often situations where that is useful. that way, you can solder ic pins with low power, reducing risk of damage, and turn up the heat when doing things that have a lot of metal, e.g., connectors or ground planes12:38
apeletewpwrak: will be using it to solder a serial line on this: http://apelete.seketeli.net/gcw-zero-board.jpg12:40
apeletedoing this on the ben nanonote was painful, that's why I'm thinking about trying with a better iron this time12:40
wpwrakyeah, you want something decent12:41
wpwrakespecially if you don't expect this to be the only thing you'll ever do with the iron12:42
apeletewpwrak: would you mind pointing a specific model ? not sure about what is selling on ebay :-(12:44
wpwrakXytronic make good stations. maybe something like this one: http://www.howardelectronics.com/xytronic/lf3000.html12:47
wpwrakor if you want cheaper, this: http://www.howardelectronics.com/xytronic/lf389D.html12:48
wpwraki general, http://www.howardelectronics.com have decent products, so you can use their catalog as a guide12:53
wpwrakthey cover the medium to high range in terms of price. so you won't find the ultra-cheap stuff that may or may not work. and they also have things with very scary prices :)12:55
apeletewpwrak: do they ship to worldwide ?12:56
apeleteit looks great, I hope they do. I might go with the cheap LF-389D model13:00
wpwrakyou should be able to find some of these products also in europe13:01
wpwrakthey do ship worldwide. i bought my 988D from them many years ago. wasn't even too expensive (these things can be heavy, especially the bigger ones)13:09
apeletewpwrak: problem is, the input power in europe is 220-240V13:14
CYB3Rpcercuei: I wanted to ask about some constants in UBIBoot. My RAM chip bus width is 16bit, it has 4 banks, 13 bits for rows, 10 bits for cols.14:12
CYB3RI'll set it like this: SDRAM_BW16 1; SDRAM_BANK4 1; SDRAM_ROW 13; SDRAM_COL 10.14:13
CYB3RBut there is also SDRAM_BANK40, SDRAM_ROW0, SDRAM_COL0. What should it be?14:13
pcercueiI'm not sure, that code is not mine14:18
pcercueibut it looks like reset values14:18
pcercueiin board-a320.c, dmcr0 is calculated from SDRAM_BANK40, SDRAM_ROW0, SDRAM_COL014:19
pcercueiand REG_EMC_DMCR is first set to dmcr0, then to dmcr14:19
pcercueiI'm don't know why it does that but it's probably needed14:20
pcercueiso SDRAM_ROW0=11 and SDRAM_COL0=8 would be the minimal row/column number the SoC can handle14:21
pcercueiwhich would make sense14:21
CYB3RLooks like SDRAM_SMTH0 is SDRAM_SMTH - 114:21
pcercueiso just don't change those14:21
pcercueino, I think it's just a coincidence14:22
nicksydneywpwrak: nice view from that camera14:40
CYB3ROkay, I'll leave those values as they are.14:41
CYB3RSDRAM_TRWL should be the value of "WRITE recovery time" from my datasheet14:42
wpwrakapelete: they tend to have 220 V options14:52
apeletewpwrak: you mean the stations actually come with 110 to 220V power regulators built in ?14:58
apeletewpwrak: I found this http://www.rapidonline.com/Tools-Equipment/Xytronic-LF-389D-60W-Digital-Display-ESD-Safe-Soldering-Station-85-678014:59
apeleteit seems to be the same one but with 220V instead of 110V15:00
apeleteI asked if it comes with a EU plug, will buy one depending on the reply15:00
wpwrakapelete: looks good15:02
wpwrak(110 vs. 220 V) no, they're usually for one voltage only. but howard often have (or at least had) a 220 V version, too.15:03
apeletewpwrak: btw, what's the benefit of having a higher power iron (eg. 60W vs 45W or 30W) when one can set the temperature like on the Xytronic ?15:08
CYB3Rpcercuei: and what value should SDRAM_TREF be? My datasheet says: "Refresh period (8,192 rows)     (tREF)  max = 64 ms"15:46
wpwrakapelete: more power = can heat up quicker, can recover from a heat loss more rapidly, can maintain higher temperatures, can heat larger areas18:10
wpwrakapelete: the main real-life benefit is the ability to heat larger areas. e.g., if you need to solder things on a large ground plane that ground plane will suck up a lot of heat. but with 60 W you'll already have some flexibility18:11
wpwrake.g., mine has 60 W and i rarely have troubles with it getting too cold. besides, reasonable layouts avoid situations where you'd be forced to solder directly on a ground plane18:12
whitequarkwpwrak: (similar problem) he's got a resistor and 555 blown out. I assumed the underlying problem was the same due to similar symptoms18:23
whitequarkand no, the forum thread just dies18:23
wpwrakhmm, pity. oh, and responses from .cn may take while due to CNY.18:26
apeletewpwrak: wow, never thought about those technical details about soldering, quite a knowledge you've got there18:26
wpwrakapelete: it's just what you notice as you solder a few things ;-)18:26
apeletewpwrak: well, let's hope having a better tools will help me get better results, I was terrible last time on the nanonote18:27
whitequarkwpwrak: ah, that's why the vendor doesn't respond... yeeeah18:27
whitequarkwhen exactly it is this year?18:28
wpwrakyeha, bad tools can make anything a nightmare. and often it's just so bad that you can't even get a clear picture of why you're having a problem18:28
wpwrakwhitequark: this week :) the new year started on the 24th, i think18:29
whitequarkok, then I will not start a ebay dispute when it suggests (at 28th)... give them the benefit of holidays18:29
whitequarkit's one week right?18:29
whitequarkwpwrak: what CAD do you use? librecad?18:53
wpwrakwhitequark: fped, and in very hackish ways :)19:26
wpwrakoh, for 2D. definitely fped.19:27
wpwrakit lacks some common 2D CAD operations but being parametric makes up for that19:28
wpwrakfor 3D, things get messy, though. i plan to have a look at FreeCAD again for that. fped can do 3D (with a little help), but it's rather non-intuitive19:28
wpwrakwhat you basically do is that you draw slices of the model. and then you give each a certain height. so it's kinda 2.5D. also, since you'll repeat some primitives a lot of times, the gui isn't very useful in this mode of operation.19:30
wpwrakthe killer feature is of course that it's parametric and that this is a "natural" part of the system19:39
whitequarkisn't it, um, slightly unfinished?19:40
wpwrakother cad systems often have several interfaces for the same task. then you can choose between "draw", "equation solver", etc.19:40
wpwrakwell, is anything ever finished ? :)19:40
whitequarklast time I tried to use it, I found it rather incomprehensible19:41
whitequarkmaybe should make another try19:41
wpwrakwhat did you expect to find but didn't ?19:42
wpwraksome limitations as CAD come from it being meant to design footprints. that's why i didn't include overly fancy geometric operations.19:42
whitequarkthat was an overall feeling. well, I guess I'll give it another try19:43
eintopfhey guys20:02
whitequarkDocScrutinizer05: actually, there IS a foss way to generate highly efficient toolpaths!20:38
DocScrutinizer05hey, nice20:40
whitequarkyep! I'm currently evaluating various foss CADs/CAMs20:41
whitequarkso far heekscad/heekscam looks the nicest20:41
DocScrutinizer05I find it a tad difficult to understand what exactly been the parameters that resulted in a picture like the one on the URL you posted, but hey...20:43
DocScrutinizer05you can guess what's the tool shape20:44
DocScrutinizer05and what's the rationale for the path, resulting from that20:44
whitequarkDocScrutinizer05: constant tool engagement angle20:46
whitequarkand least amount of tool entries20:46
whitequarkthis allows to maximize speed within the tool's operating range, and reduce wear20:46
whitequark(TEA = the percentage of tool's circumference which is cutting at any given time)20:46
whitequarkheekscad really doesn't want to install itself though20:54
rohwhitequark: heeks is nice. but needs some work/was crashy last time i checked.. and it seems development moved on21:19
whitequarkroh: yeah it appears so21:22
whitequarkI don't really see any OSS on the level of heeks21:22
whitequarkwell, there's openscad, but it's a very different kind of software21:23
whitequarkdo you know anything?21:23
rohnope.. i thought the developers moved on to freecad plugins or so21:24
whitequarkfreecad looks kinda nice too21:26
rohhavent used it or looked at it recently21:27
rohin the end basically all toolpathes i've used were composites of generated gcode and some manual editing21:30
whitequarkyeah, I understood so much from what I read about gcode21:30
whitequarkso far I'm searching for a good tool to make some of grunt work for me21:30
whitequarkfreecad does look like one, plus I guess heeks won't want to work on a crappy one21:31
whitequarkopenscam has a nice simulator21:31
rohi'd like to have some cam working on openscad data21:32
whitequarkit's despite its name not a cam :D21:32
rohlike parametric cam for parametric cad... best in one tool21:32
rohi know.21:32
rohand that simulator from openscam plays in there nicely21:32
whitequarklooking at freecad, it definitely looks like a nice tool21:35
whitequarkthe parametric bit seems to be "let's just add a python api and see how that works"21:38
paul_boddieI looked at the version of FreeCAD in Debian Sid the other day, but the Python stuff kept failing.22:00
paul_boddieUnfortunate when the export functions are written as Python extensions.22:00
whitequarkI'm following this tutorial: http://freecad-tutorial.blogspot.ru/2011/09/engine-1-piston-pin-and-pin-ring.html22:00
paul_boddieSo I started using OpenSCAD more seriously instead.22:01
whitequarkso far I'm liking it a lot, it seems both powerful and quite understandable22:01
whitequarkand I don't exactly like openscad's scripting approach22:01
whitequark[for me] textual programs work for abstract stuff like networks and algorithms, but not physical objects22:01
paul_boddieFreeCAD has some nice features, albeit confusingly presented.22:02
paul_boddieOne thing that shows the difference between the two is the thing known as filleting where you smooth off edges.22:02
paul_boddieIn FreeCAD there are two tools for that - you're not supposed to use "the wrong one", which I managed to avoid by chance - whereas in OpenSCAD it's an FAQ.22:03
paul_boddieI figured it out in OpenSCAD, anyway: you just cut a cylinder out of a block and then substract the remainder from whatever you want to fillet.22:04
paul_boddieBut yes, there's a lot of sitting and thinking (and using your fingers to visualise things, "old school") with OpenSCAD.22:05
paul_boddieAnd I'm not sure how well suited it is to producing models that can be machined using traditional tools, although wpwrak may have something to say about that.22:06
paul_boddie(Wow, Ubuntu One not exactly "mission critical" stuff: http://freecad-tutorial.blogspot.no/2011/09/engine-1-piston-pin-and-pin-ring.html#comment-1212081032)22:07
Action: paul_boddie took a risk there with the regex!22:08
wpwrakthe fillet ting in openscad means of course that you can't just "fillet" an edge but that you have to consider the whole geometry. this can get messy.22:10
wpwrakpaul_boddie: haven't tried to real-life machine from either. only a bit from heekscad and then a lot with fped22:11
paul_boddieI was doing a design the other day, and I was generally thinking in terms of how you'd machine it.22:15
paul_boddieBut I'm not sure if there are tools to try and convert the operations to actual machining operations.22:16
paul_boddieI think you'd have to declare such things explicitly, anyway, since CSG allows for some pretty strange stuff.22:17
paul_boddieAs in that filleting where the machine would happily cut out the cube, but then flip out upon being told to "negate" it to round off edges. :-)22:18
paul_boddieSpecify an antimatter cube to begin with...22:18
wpwrakah no, the cam part of the cad system should translate that ;-)22:18
wpwrakantimatter cube is a possibility. but you need pretty strong containment fields ...22:19
paul_boddieEasier to go the 3D printer route at that point. ;-)22:19
whitequark3D printing still requires a CAM, but apparently it's much simpler to do22:22
wpwrakdunno. both have their specialities.22:23
paul_boddieI guess that if you're just doing a layer-by-layer print then the STL file is good enough.22:24
whitequarkyou need to print supports and such22:25
paul_boddieI saw some 3D printing going on last weekend at a Maker Faire. It was quite the fashion.22:32
paul_boddieA lot of it seemed to involve mostly the same kind of MakerBot device or whatever it is called.22:32
whitequark(fashion) in what sense?22:34
paul_boddieMeaning that a lot of people was doing it. There was some other "maker" stuff going on, too, but 3D printing was all over the place.22:35
paul_boddieGrrr! qi-bot applies global search and replace without the "g" flag!22:36
paul_boddieThese people were showing a simple-looking printer: http://blog.polarworks.no/22:38
paul_boddieNot sure if it really cuts it, though.22:38
wpwrak3d printing is nice. very versatile, quiet, clean. cnc milling on the other hand is: precise, takes many materials, but shapes are limited (no overhangs with a 3 axis mill), noisy, and produces copious amounts of dust22:54
wpwrakso 3d printing is a bit more on the art side while cnc is more on the engineering side22:57
wpwraknow divide potential art critics by the number of potential engineers and you have the ratio :)22:57
roh3d printing is great for prototyping, but you should not expect proper measurements with devices below a few thousand euros23:16
rohfdm isnt great at keeping tolerances down23:16
rohthe powder and 'soup' style stuff is better on that.. but hey.. it has its usecases23:17
rohyep. in its different variants23:32
rohpower and liquid23:32
roheh powder23:32
rohform1 stuff looks really impressive23:32
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