#linuxcnc | Logs for 2013-01-26

[02:03:45] <DJ9DJ> moin
[04:02:32] <roh> heho.
[04:02:41] <roh> i wonder if this would be a good platform for emc2 http://www.gizmosphere.org/why-gizmo/gizmoboard/
[04:03:01] <roh> seems nice and low power but still should have some gl punch and fast io
[06:10:52] <Valen> looks like it could be made to work
[06:10:57] <Valen> roh
[06:11:07] <Valen> but i do wonder if there's alot of point
[06:11:24] <Valen> if the GPIO is memory mapped it'd be neat but odds are its through some I/O card
[06:48:46] <Tecan> would putting a thermal fuse under a laser work well ?
[06:49:01] <Tecan> http://i.imgur.com/Mf4zP5E.jpg
[06:49:49] <Tecan> maybe some steel ontop of it
[06:50:47] <Tecan> should be a good if it shoots through the workpeice shut off machine
[06:51:11] <archivist> yes/no/maybe/does it need it/dunno
[06:51:32] <Tecan> put some on the motors and ps too
[06:51:45] <archivist> those thermal things are not fast
[06:52:00] <Valen> lasers cut metal
[06:52:03] <Valen> thats made of metal
[06:52:07] <Valen> this seems like a bad plan
[06:52:11] <Tecan> Valen not small ones
[06:52:28] <Valen> also the whole point of lasers as a rule is to pass through the material being cut
[06:52:29] <Tecan> my 40 has a hard time cutting acrylic
[06:55:19] <archivist> steel is also a poor heat conductor, so you will be burning through one part while the thermal cut out is 6" away as cool as a cucumber laughing
[06:57:41] <Valen> what are you really trying to prevent?
[07:01:57] <Valen> if its burning through the tray underneath, most people just put water in it
[07:20:50] <Loetmichel> Tecan: put a flat trough with blackened water under your workpiece, much safer
[07:21:30] <Tecan> flat through ?
[07:22:15] <Loetmichel> tub, tray, whatever you call it,. solething that can handle 5cm high of water witout dripping and is large enough for the working area
[07:23:01] <Tecan> ya but i want the machine to shut off not evaporate all the water also hv and water dont mix well on a desktop
[07:24:29] <Tecan> i see what your saying though if im going to laze right through something
[07:25:14] <Tecan> safer on the eyes and wont make the machine weigh a ton
[07:26:08] <archivist> the black trough of water becomes a safe heatsink
[07:26:34] <Tecan> activated charcoal
[07:38:30] <Loetmichel> will ignite
[07:39:41] <Loetmichel> Tecan: thats the way to go, even 20kW industrial lasercutter work this way.
[07:40:31] <Loetmichel> there is the water 50cm deep and pitch black and instant boiling about 30cm deep at full power but it works
[07:40:35] <Loetmichel> :-)
[07:42:04] <Tecan> ok so the bottom is black or whats in the water ?
[07:44:10] <Tecan> just so i dont make a mess here :)
[07:47:43] <Tecan> neat they use ruby lasers for tatoo removal
[07:47:56] <Tecan> The Ruby laser is most effective on tattoos with green, blue and black pigments. It is less effective on red, yellow and orange pigments
[07:48:34] <Tecan> wonder what it would take to become a tatoo removal guy
[07:49:21] <jdh> a laser
[07:49:25] <Tecan> lol
[07:49:56] <jdh> http://dx.com/p/tattoo-starter-kit-gun-supply-set-equipment-97087
[07:50:08] <jdh> for $50, you can become a tattoo guy
[07:50:24] <Tecan> yeah that might not look so well unless i could cnc the outline
[07:50:55] <jdh> touch offs could be a problem
[07:51:05] <Tecan> :)
[07:51:32] <jdh> "sorry about your testicles, I thought it was G54"
[08:17:03] <Tecan> http://www.dumpaday.com/wp-content/uploads/2013/01/funny-wifi-fbi-survelience-van.jpg
[09:18:30] <Jymmm> Heh http://dx.com/p/mini-aluminum-tattoo-machine-power-supply-110-240v-us-plug-97008?rt=1&p=2&m=2&r=3&k=1&t=1&s=97088&u=97008
[09:19:46] <Jymmm> cute lil variable dc PS
[09:21:05] <Loetmichel> jdh: thats the kind of tatoo guy where you get this: http://www.teamjimmyjoe.com/wp-content/uploads/2012/04/BadTattoosLegDog.jpg
[09:21:06] <Loetmichel> ;-)
[09:22:30] <Jymmm> wth?! lol
[09:24:09] <theos> the dog has 4 eyes! its a miracle... oh wait
[09:25:39] <Gabe_W> how do i aquire the *data_ptr_addr from hal shared memory? Is it essential to include hal_priv.h?
[09:31:32] <Gabe_W> im writing a hal wrapper in cython, and im stuck on that aspecdt
[09:31:37] <Gabe_W> aspect*
[09:40:07] <micges> Gabe_W: try on #linuxcnc-devel channel
[09:40:37] <Gabe_W> Usually those that are on there, are on here :)
[09:41:13] <micges> true
[09:45:32] <JT-Shop> what is cython?
[09:46:20] <Jymmm> Cython is a language that makes writing C extensions for the Python language as easy as Python itself. It is based on the well-known Pyrex, but supports more ...
[09:46:45] <Gabe_W> its speeds python code a substantial amount
[09:47:04] <Gabe_W> i only write in it, if im doing complex number crunching or wrapping c code
[09:51:54] <JT-Shop> neat
[09:55:25] <Gabe_W> yeah this is WillenCMD for those that remember
[09:58:22] * archivist wonders if someone has managed to scan a barber colman manual :)
[09:58:38] <Gabe_W> lol, i should just mail it to you
[09:58:43] <Gabe_W> we have a dozen of them
[09:59:42] <archivist> not that I am restoring it at the moment as it is too damned cold out in the garage
[10:02:50] <archivist> andypugh, re last nights comment about cycloidal teeth, back in the dark ages even the originals were hand filed and not to any standard, to repair by filing is the right way
[10:03:33] <andypugh> It's the _traditional_ way I will grant you :-)
[10:06:47] <archivist> andypugh, I mean they were manufactured that way, nothing to do with tradition
[10:07:08] <archivist> before wheel cutting engines
[10:08:04] <andypugh> Well, then, the right way is to accurately measure all the teeth, work out what the average profile was, then make a special cutter to exactly reproduce what the original maker thought a gear tooth should look like :-)
[10:08:58] <archivist> spherical objects, use a file like the ye olde world
[10:10:41] <archivist> dunno if you have seen the characteristics of one done that way, look at the root of the teeth, will have an approx repeating pattern every 5/6 teeth from the filing jig
[10:12:05] <andypugh> I saw a guy making a gear with only a file on a programme about the Antithikera mechanism. It seemed to come out pretty well.
[10:13:00] <archivist> not seen that program yet
[10:33:40] <archivist> I was searching for broken and non working things on fleabay and found 330859591148
[10:35:49] <Jymmm> lol
[10:38:45] <archivist> I kept it in my watch list to see what happens
[11:21:03] <Tom_itx> 0 bids?
[11:21:17] <Tom_itx> not even his mom?
[11:21:30] <jdh> she knows better.
[12:11:59] <IchGuckLive> hi all b9
[12:35:43] <DJ9DJ> hu
[12:36:17] <IchGuckLive> O.O
[12:58:41] <Tom_itx> i wonder if a washer motor & control unit would make a good spindle motor
[13:00:48] <pcw_home> Any is going to try one on a lathe (and they wont spin very fast)
[13:00:53] <pcw_home> Andy
[13:01:29] <Tom_itx> about 1600 rpm
[13:02:21] <Tom_itx> i wonder how hard they are to hack into the signal
[13:02:33] <Tom_itx> it looks like it's got PWR GND and signal
[13:02:46] <Tom_itx> surely not just simple pwm
[13:02:50] <IchGuckLive> someone knows a good kombination for a stepper motor 400steps/Rotation gear and a rack
[13:02:52] <pcw_home> The controller?
[13:02:56] <Tom_itx> yes
[13:03:06] <pcw_home> serial?
[13:03:12] <Tom_itx> could be, i dunno
[13:03:45] <pcw_home> maybe its just async 9600 baud or some such
[13:04:02] <Tom_itx> i'm gonna give it one more chance as it's life started out then i'll pull the electronics and scrap the rest
[13:04:03] <Connor> http://www.cnczone.com/forums/benchtop_machines/172411-mach_3_vs_linux_cnc.html
[13:04:06] <Connor> Ugg. :(
[13:04:09] <Connor> Stupid people.
[13:04:21] <Tom_itx> replacing bearings in it today
[13:04:28] <Tom_itx> the drum that is
[13:05:16] <pcw_home> 1600 RPM mus be spin cycle
[13:05:27] <Tom_itx> no, that's the motor rating
[13:05:33] <Tom_itx> large pulley on the drum
[13:05:41] <Tom_itx> probably 30:1 or more
[13:05:57] <Tom_itx> maybe not quite that much
[13:06:05] <pcw_home> Oh I thought this was one of those direct drive thingys
[13:06:10] <Tom_itx> about 14" pulley
[13:06:11] <Tom_itx> no
[13:06:20] <Tom_itx> and maybe a 1" or so one on the motor
[13:06:57] <Tom_itx> i wonder if it's 3phase or just a standard dc motor
[13:08:22] <pcw_home> how many wires?
[13:13:40] <Tom_itx> i'll have to check
[13:13:59] <andypugh> Tom_itx: The motor I want to experiment with is direct-drive
[13:14:20] <Tom_itx> one of those fisher packyl ones?
[13:14:35] <andypugh> It's a rather large brushless motor: https://picasaweb.google.com/lh/photo/IyoF5obSvIRdd9xn6yIL1NMTjNZETYmyPJy0liipFm0?feat=directlink
[13:14:41] <andypugh> Actually made by LG
[13:15:11] <andypugh> And fairly cheap: http://www.amazon.co.uk/LG-Electronics-Washing-Assembly-4417EA1002G/dp/B0098MM8CY
[13:15:18] <Tom_itx> very similar though
[13:17:27] <andypugh> I reckon if it can throw soggy socks around in a drum then it ought to make quite a lot of torque :-)
[13:24:51] <pcw_home> torque rating in soggy-socks?
[13:26:04] <Tom_itx> haha
[13:26:18] <pcw_home> have you measured the winding resistance? That will give you an idea of how much current it will take
[13:26:30] <Tom_itx> the manual says it's a 3 phase sync induction motor
[13:26:43] <Tom_itx> with a tach
[13:27:10] <pcw_home> Tom_itx: on yours?
[13:27:13] <Tom_itx> yes
[13:27:34] <pcw_home> so its a 3 phase BLDC servo motor
[13:27:53] <pcw_home> or PMSM for purists
[13:27:55] <Tom_L> http://adcxns1.whirlpool.com/Service/SrvTechAdm.nsf/2cd44500d572193285256a45004fd9d6/eab852a13fbc842085256aa200643dd6/$FILE/Duet%20Job%20Aid.pdf
[13:27:59] <Tom_L> P 9
[13:28:40] <Tom_itx> err 3.9
[13:29:54] <awallin> hm so did people DIY the rotors around those stators? with neodym magnets? any good?
[13:31:15] <Tom_itx> pcw_home, P5.4 says it's serial
[13:31:40] <pcw_home> and bidirectional
[13:31:44] <Tom_itx> yes
[13:32:05] <Tom_itx> like an 8bit word for speed and direction?
[13:32:59] <pcw_home> awallin not sure how much you would gain with rare earth magnets if the iron is close to saturation
[13:33:24] <andypugh> awallin: I got the rotor too, original LG part.
[13:33:42] <pcw_home> Hard to guess on a bidirectional one wire protocol
[13:34:03] <Tom_itx> it's probably not 5v either
[13:34:14] <Tom_itx> if it were i could hook my analizer on it
[13:34:50] <pcw_home> Is this a junk washer or just the parts?
[13:35:09] <andypugh> I am not sure what anyone is talking about any more.
[13:35:16] <Tom_itx> i'm still using it but it's on it's last leg
[13:35:25] <pcw_home> two washer motors at once
[13:35:38] <Tom_itx> andypugh i just linked the pdf to mine
[13:36:05] <Tom_itx> i'm gonna give the bearings one more go then i'll scrap it out
[13:37:22] <pcw_home> If you can spy on its communication you might be able to grok it and use its controller for a spindle control
[13:38:02] <pcw_home> (make sure its isolated from the line!)
[13:38:45] <Tom_itx> that was the hope
[13:38:50] <pcw_home> I would expect its isolated but thats just a guess
[13:40:19] <pcw_home> andypugh: have you measured the line-line resistance on your motor?
[13:40:50] <awallin> so would washing-machine motors make good motors for positioning purposes? (rotary table? direct drive of ballscrew, etc)
[13:41:40] <Tom_itx> certainly worth a try before scrapping them
[13:41:47] <pcw_home> Possibly, though the have more rotational inertia than purpose built servo motors
[13:42:11] <pcw_home> just add an encoder and you have a AC servo
[13:57:07] <tjb1> https://www.dropbox.com/s/3aurjmtbnvcvv8r/2013-01-26%2014.40.48.jpg
[14:01:09] <ReadError> you not get black clips?
[14:02:30] <tjb1> not yet, im gonna go to wally here soon
[14:27:52] <andypugh> pcw_home: 8.4 Ohms
[14:28:48] <pcw_home> Yeah so it must be something like 1 HP (2.2 KW peak maybe)
[14:30:04] <pcw_home> 10A RMS would be way to much power dissipation
[14:32:05] <andypugh> I doubt it is intended to make much power at low rpm.
[14:32:40] <andypugh> It might be completely useless, but it looks like fun to find out,
[14:41:10] <pcw_home> so about 3.5A RMS is ~ 1 HP and maybe 100W of heat
[14:42:01] <pcw_home> which should be OK (maybe mount stator on Alu plate?)
[14:57:20] <andypugh> It's pretty big, 100W sounds like it would stay quite cool.
[14:57:33] <andypugh> There are air-stirrers in the rotor too.
[15:02:42] <pcw_home> Yeah just dont put 30A through it for very long
[15:03:37] <pcw_home> on the other hand its is mostly open so you would smell the insulation/notice the smoke...
[15:04:38] <pcw_home> you will need to keep magnetic swarf out
[15:06:52] <andypugh> Yes, some sort of cover is probably in-order :-)
[15:07:15] <pcw_home> I should say dont put 10A though it (nominally 2.2KW) for very long
[15:07:25] <andypugh> I reflashed the 7i73 today. It still works :-)
[15:07:46] <pcw_home> 10A might be a good peak current setting though
[15:08:12] <andypugh> I would probably start even lower than that, and run a thermocouple.
[15:09:38] <pcw_home> Thats good, I still need to flash a different version to make sure its really writing but Im pretty sure it is (since it was writing in the wrong places before)
[15:11:19] <pcw_home> So if you dont have enough torque at low speeds can you help by using the rotor as a handwheel?
[15:15:20] <andypugh> I guess you could, but part of the motivation was to not have to hand-crank the spindle :-)
[15:22:30] <pcw_home> is this going to be tested on the lathe you did the hex cutting with?
[15:23:28] <ReadError> tjb1
[15:23:30] <ReadError> get some hairspray
[15:23:45] <ReadError> i got some called 'samy'
[15:23:48] <ReadError> in a blue bottle
[15:23:49] <ReadError> works good
[15:23:51] <ReadError> aerosole
[15:28:21] <andypugh> pcw_home: Tested. yes. Probbaly not used though
[15:30:14] <pcw_home> Does sounds interesting for a low speed high torque orientable spindle
[15:32:57] <andypugh> Not even such low speed, 1400rpm is the washing machine speed. It might run faster with a different controller.
[15:33:30] <tjb1> already back ReadError
[15:33:36] <tjb1> Had to get massive binder clips
[15:34:54] <Gabe_W> tjbl your still here huh?
[15:35:30] <tjb1> Im always here
[15:35:44] <Gabe_W> but your never there
[15:35:53] <pcw_home> Well I mean low speed compared to normal 2 or 4 pole BLDC motors
[15:36:06] <tjb1> Never where
[15:38:22] <tjb1> Gabe_W: I am everywhere
[15:38:56] <pcw_home> turn over a stone, I am there...
[15:39:09] <tjtr33> andypugh, maybe of use http://www.thebackshed.com/Windmill/Contents.asp they work a lot with those washing machine motors ( tho they use 'em as gnr8rs )
[15:41:02] <tjtr33> i thought the low speed cogging info might be of interest
[15:42:25] <andypugh> Cogging would be a definite drawback if using it in trapezoidal mode, I think it would show in the surface finish.
[15:42:50] <andypugh> I would be wanting to use an encoder and sinusoidal commutation.
[16:35:13] <DJ9DJ> gn8
[17:51:35] <JT-Shop> how hard would it be to make and ignitor like this? http://ultimatespudgun.com/30kv-igniter-p-219.html
[18:04:53] <Tom_itx> what about a grill igniter>
[18:04:57] <Tom_itx> ?
[18:05:10] <JT-Shop> that's what I'm using now but it is not reliable
[18:05:28] <Tom_itx> what about a furnace spark igniter
[18:05:33] <Tom_itx> or stovetop
[18:05:42] <Tom_itx> they 'tick' until they light
[18:05:53] <JT-Shop> those are 120v
[18:06:22] <JT-Shop> mine uses a glow thingy, I don't think the wife will like it if I remove it
[18:07:00] <skunkworks> tazer?
[18:07:15] <Tom_itx> you want it for your cannons?
[18:07:23] <JT-Shop> tator gun
[18:07:48] <Tom_itx> i doubt you could make one any cheaper than that
[18:08:17] <skunkworks> JT-Shop: I found that adding mulible spark gaps down the center of the chamber really helps speed up the burn.....
[18:08:17] <JT-Shop> I'd bet your right
[18:08:48] <skunkworks> multiple
[18:09:02] <Tom_itx> find an old model T coil
[18:09:08] <JT-Shop> I read somewhere that having the igntor in the middle is the best for propagation of the flame
[18:09:20] <JT-Shop> to get the highest pressure
[18:09:35] <Tom_itx> or some old magneto setup
[18:09:55] <JT-Shop> I did a mod to mine today and cut a small bevel on the ID and it made the tators seal better with a tad of compression
[18:09:57] <Tom_itx> that probably wouldn't work so good for this though
[18:10:06] <skunkworks> I ran a fiberglass rod down the center of the combustion chamber with 3 or 4 spark gaps in series.
[18:10:23] <skunkworks> it was a substantial improvement...
[18:10:42] <JT-Shop> you using a push button grill ignitor?
[18:10:58] <skunkworks> suspended with a screw on each end which also ran the power in..
[18:11:06] <skunkworks> I did - yes - this was quite a few years ago)
[18:12:33] <skunkworks> I don't remember having much issue with it... But as I say - long time ago. I think I had to pull the spark gap assembly every so often to clean.. (I was using aquanet hair spray)
[18:13:10] <JT-Shop> we use white rain and if you spray it on the ignitor you have to clean it off
[18:13:42] <AR__> 8 threaded rods through aluminum extrusion column
[18:13:42] <skunkworks> also - green hickory nuts that just fit the barrel really work nice.... ;)
[18:13:43] <AR__> http://i.imgur.com/I0Qwxw5.jpg
[18:13:53] <AR__> quite sturdy!
[18:29:24] <JT-Shop> http://www.youtube.com/watch?v=8ux9o8DH6f4
[18:32:47] <skunkworks> JT-Shop: there you go :) - though - like I say - use multiple spark gaps down the center of the chamber....
[18:38:32] <skunkworks> although I might wrap the chamber with cloth... Just in case...
[18:44:48] <JT-Shop> I was thinking of 14ga steel wrap... just in case
[18:45:04] <skunkworks> canvas
[18:55:39] <JT-Shop> say goodnight Gracie
[18:57:01] <Jymmm> G'night Groucho
[18:57:23] <AR__> http://www.youtube.com/watch?v=UMJ3eCHZtGY
[18:57:26] <AR__> this one looks better
[19:21:32] <r00t4rd3d> http://imgur.com/a/IHRjO
[19:21:35] <r00t4rd3d> what it is?
[19:27:30] <Jymmm> it's a writer
[19:27:45] <Jymmm> 45's I believe
[19:57:33] <Jymmm> JT-Shop: 1991 Goldwing ENGINE GL1500 http://sfbay.craigslist.org/sby/mcy/3569798994.html
[21:33:29] <Tecan> yarrr
[23:11:20] <r00t4rd3d> http://i.imgur.com/OZebY.png