#emc | Logs for 2005-10-08

[00:05:11] <alex_joni> evening
[00:12:10] <ValarQ> g'deve
[00:12:26] <alex_joni> hey captain
[00:12:45] <ValarQ> how it going civilian?
[00:13:02] <alex_joni> * alex_joni is tired
[00:13:06] <alex_joni> long day ..
[00:13:11] <ValarQ> same here
[00:13:17] <alex_joni> 2 customers + 10h drive home
[00:13:23] <ValarQ> that bed sure looks comfortable now
[00:13:38] <alex_joni> it sure feels like that
[00:13:39] <ValarQ> it's calling for me...
[00:15:15] <alex_joni> right
[00:15:24] <alex_joni> ValarQ: you were located in sweden, right?
[00:15:30] <ValarQ> alex_joni: yeah
[00:15:40] <alex_joni> * alex_joni is going to sweden on monday
[00:15:45] <ValarQ> alex_joni: oh
[00:15:52] <alex_joni> ;)
[00:15:53] <alex_joni> Lund
[00:16:18] <ValarQ> skåneland :)
[00:16:30] <alex_joni> wot's that?
[00:17:24] <ValarQ> thats eh, an alternative name for the, eh state
[00:17:41] <alex_joni> don't think I want to know what that means :D
[00:17:50] <alex_joni> where r u located in sweden?
[00:18:01] <ValarQ> well, i don't know a good english name for landskap
[00:18:09] <ValarQ> alex_joni: i'm located near Kalmar
[00:18:19] <ValarQ> alex_joni: not that far from Lund actually
[00:19:57] <ValarQ> well, pretty far
[00:20:25] <alex_joni> heh
[00:20:27] <ValarQ> i don't wan't to walk it...
[00:20:35] <alex_joni> lol... no cars around there?
[00:20:51] <ValarQ> sure
[00:21:11] <ValarQ> but i'm from Småland
[00:21:26] <alex_joni> ok... :-?
[00:21:28] <ValarQ> and we are known to be stin... eh very economical ;)
[00:21:39] <alex_joni> scottish like?
[00:22:09] <ValarQ> dunno, i don't know any scottish people
[00:22:23] <ValarQ> not outside of irc anyway
[00:23:21] <alex_joni> they are famous for beeing .. "economical", as you put it
[00:23:28] <ValarQ> ok :)
[00:23:48] <ValarQ> why are you going to skåneland?
[00:25:25] <ValarQ> oh well, i'm bushed, g'dnite folks
[00:25:44] <ValarQ> * ValarQ snores like a little pig
[00:26:40] <alex_joni> night
[00:26:48] <alex_joni> ValarQ: going to a meeting to the Lund university
[00:49:24] <anonimasu> :/
[00:49:27] <alex_joni> * alex_joni goes to bed too
[00:49:36] <alex_joni> hey anders
[00:49:44] <anonimasu> hey what's up?
[00:49:55] <alex_joni> tired
[00:50:12] <alex_joni> been mostly away from home lately
[00:50:35] <anonimasu> I know the feeling :/
[00:50:39] <alex_joni> how about you?
[00:50:45] <alex_joni> didn't see you much lately
[00:51:38] <alex_joni> darn... falling asleep
[00:51:43] <alex_joni> talk to you tomorrow
[00:51:45] <anonimasu> yeah
[00:51:46] <alex_joni> or sunday
[00:51:48] <alex_joni> :/
[00:51:49] <anonimasu> yep
[00:52:17] <alex_joni> 18h / day is too much ;)
[00:52:35] <alex_joni> nah.. 17
[00:52:49] <alex_joni> ok.. night
[01:58:48] <Jacky^> night
[02:32:34] <icee> last -msg
[02:32:36] <icee> er
[03:18:46] <Jymmm> boo
[04:16:07] <Luminous> HOLA
[04:16:11] <Luminous> HOLA
[04:16:16] <Luminous> wat ups
[11:43:10] <alex_joni> morning
[11:43:28] <ValarQ> mornin
[11:43:32] <anonimasu> Hey alex..
[11:43:40] <anonimasu> anyone of you good at electronics?
[11:43:44] <alex_joni> so you guys are here :)
[11:43:49] <alex_joni> * alex_joni is a bit
[11:43:56] <alex_joni> what's your problem?
[11:44:10] <anonimasu> I am trying to convert a 0-5v analog signal to a 5-0v one
[11:44:17] <anonimasu> with a lm741cp
[11:44:35] <alex_joni> you need to have +/-5V supply for that to work
[11:44:55] <alex_joni> at lest I didn't manage to make it otherwise
[11:45:01] <alex_joni> invert it, then bias it
[11:45:14] <anonimasu> could you draw a schematic?
[11:45:20] <anonimasu> but I think my error might be that I lack -5v
[11:45:42] <anonimasu> I just have +5v and gnd
[11:45:48] <alex_joni> that's what my error was too
[11:45:54] <anonimasu> hm, nice!
[11:46:15] <alex_joni> anonimasu: http://www.facstaff.bucknell.edu/mastascu/eLessonsHTML/OpAmps/OpAmp2A01.gif
[11:46:21] <alex_joni> a simple inverting opamp
[11:46:26] <alex_joni> R1=R2
[11:46:46] <anonimasu> that's the hookup I have..
[11:46:56] <anonimasu> and a voltage divider on
[11:46:58] <anonimasu> +
[11:47:10] <alex_joni> but that will only make 0..-5 V
[11:47:16] <alex_joni> out of your 0-5V signal
[11:47:30] <alex_joni> given that you have the -5/5V supply on the opamp
[11:47:58] <anonimasu> hmm ok
[11:48:07] <anonimasu> how would I get it from 5-0v instead?
[11:48:30] <alex_joni> a bit harder..
[11:48:35] <alex_joni> not sure..
[11:48:38] <alex_joni> * alex_joni is thinking
[11:49:04] <anonimasu> ok
[11:51:38] <alex_joni> don't think you can
[11:51:44] <alex_joni> you need negative supply voltage
[11:51:48] <alex_joni> not much current though
[11:52:03] <alex_joni> * alex_joni wonders if you cannot generate that from 5V
[11:52:10] <anonimasu> yes with a max232
[11:52:10] <anonimasu> ;)
[11:52:23] <alex_joni> heh.. yeah
[11:53:35] <alex_joni> you might want to read this: http://www.du.edu/~etuttle/electron/elect21.htm
[11:54:35] <anonimasu> dosent help much since I have no idea what what I want to do is called
[11:55:00] <alex_joni> you want inverting and bias
[11:56:34] <alex_joni> http://www.techlib.com/electronics/splitsupply.htm
[11:59:02] <anonimasu> isnt that what I am doing with the voltage divider..
[11:59:33] <alex_joni> well.. you can't generate neg. voltages with avoltage divider
[11:59:50] <anonimasu> I dont want a negative voltage
[12:00:03] <alex_joni> but you need it...
[12:00:06] <anonimasu> I want the voltage off this sensor to go from 0.5v to 5-0v
[12:00:13] <alex_joni> right
[12:00:15] <anonimasu> I can generate +10/-10v easily :)
[12:00:25] <alex_joni> you can?
[12:00:32] <anonimasu> yes..
[12:00:37] <anonimasu> err 0 to 5v to 0 to 5v
[12:00:42] <anonimasu> off 5v
[12:00:57] <alex_joni> didn't get that
[12:01:08] <anonimasu> a max232cpe has a 0-10v voltage doubler and a +10v to a -10v voltage inverter
[12:01:17] <anonimasu> err
[12:01:26] <anonimasu> 0 to 5v -> 5 to 0 v
[12:01:53] <alex_joni> still don't get it
[12:02:02] <alex_joni> what works and what doesn't?
[12:02:40] <anonimasu> nothing right now :)=
[12:03:20] <alex_joni_> got disconnected
[12:03:29] <anonimasu> err nothing works right now
[12:03:42] <alex_joni_> ok
[12:03:48] <alex_joni_> let's take it step by step
[12:03:51] <anonimasu> ok
[12:03:54] <alex_joni_> what's the first thing you tried
[12:04:25] <anonimasu> I hooked up the opamp with a voltage divider in on pin 3
[12:04:37] <anonimasu> and input on pin 2
[12:04:50] <anonimasu> with a resistor, for the input line and another one for the gain..
[12:04:55] <alex_joni_> got a schem? or link?
[12:05:01] <anonimasu> no, not right now
[12:05:03] <anonimasu> I can get one
[12:05:05] <alex_joni_> ahh .. I see
[12:05:09] <alex_joni_> nm
[12:05:29] <alex_joni_> what value on the voltage divider?
[12:06:20] <anonimasu> 6.21k
[12:06:33] <alex_joni_> I mean Volts
[12:06:55] <anonimasu> 2.5v
[12:07:08] <alex_joni_> did you want to split the 5V in half?
[12:07:12] <alex_joni_> right
[12:07:30] <alex_joni_> so on V+ you have 2.5V and on V- the input signal
[12:07:41] <anonimasu> yes
[12:07:42] <alex_joni_> what
[12:07:51] <alex_joni_> what's the measured voltages on output?
[12:08:07] <alex_joni_> * alex_joni_ would figure close to 0
[12:08:22] <anonimasu> hm cant remember right now, I need to hook up the power supply
[12:08:33] <alex_joni_> ok.. do that
[12:08:35] <alex_joni_> :)
[12:10:22] <Jacky^> morning
[12:13:41] <anonimasu> alex_joni: I have a schematic now
[12:13:52] <alex_joni_> link me
[12:14:56] <anonimasu> http://www.bojn.net/~an0n/schematic1.gif
[12:15:45] <alex_joni_> out is 6 not 7
[12:16:02] <Jacky^> optoisolator ?
[12:16:05] <alex_joni_> problem with this schematic is:
[12:16:11] <anonimasu> my drawing sucks.
[12:16:12] <alex_joni_> 1. you biased the signal by 2.5V
[12:16:18] <alex_joni_> anonimasu: nevermind that
[12:16:24] <anonimasu> the main problem is that I have no clue ;)
[12:16:30] <alex_joni_> right :D
[12:16:39] <anonimasu> continue please ;)
[12:16:40] <Jacky^> anonimasu: what is ?
[12:17:08] <alex_joni_> I'm thinking (googling)
[12:17:25] <anonimasu> Jacky^: a opamp
[12:17:35] <Jacky^> to do ?
[12:17:58] <anonimasu> convert a 0v to 5v signal to a 5v to 0v signal
[12:18:29] <Jacky^> uhmm
[12:18:47] <Jacky^> i used some ls74 to do that ..
[12:19:09] <anonimasu> ls74?
[12:19:11] <Jacky^> 7434
[12:19:17] <Jacky^> or 7408
[12:19:31] <Jacky^> it depend on which conversion
[12:20:34] <anonimasu> *thinks*
[12:20:35] <Jacky^> 3 output for each
[12:20:39] <alex_joni_> Jacky^: got a link?
[12:20:42] <anonimasu> how advanced would a circuit like that be?
[12:20:53] <Jacky^> i used it for my optoswitches
[12:20:59] <Jacky^> maybe ive the link
[12:21:01] <Jacky^> a moment..
[12:21:07] <anonimasu> err how many components..
[12:21:08] <anonimasu> that is
[12:21:32] <anonimasu> my electronic retailer is offline
[12:21:52] <alex_joni_> alex_joni_ is now known as alex_joni
[12:22:06] <alex_joni> anonimasu: it would be nice to know what values you get out of that schematic
[12:22:13] <alex_joni> for 0V (output is...)
[12:22:20] <alex_joni> for 2.5V (output is...)
[12:22:23] <anonimasu> I ned to shower before testing it..
[12:22:28] <alex_joni> for 5V (output is...)
[12:22:29] <alex_joni> ok
[12:22:32] <Jacky^> http://www.roboitalia.com/modules.php?name=coppermine&file=displayimage&album=146&pos=3
[12:22:44] <Jacky^> that is the 7432
[12:23:10] <Jacky^> + 5 V in input = 0 in out
[12:23:17] <anonimasu> analog also?
[12:23:23] <alex_joni> Jacky^: we are talking analog here
[12:23:26] <Jacky^> ttl
[12:23:29] <alex_joni> not inveting a TTL signal
[12:23:32] <Jacky^> :\
[12:23:34] <alex_joni> inverting
[12:23:45] <Jacky^> sorry then ..
[12:23:52] <Jacky^> :(
[12:23:58] <anonimasu> :/
[12:26:20] <alex_joni> anonimasu: thought of a crazy way ;)
[12:26:22] <CIA-8> 03paul_c * 10emc2-auto/wiki/ (6 files in 4 dirs): "Auto update wiki from a cron job. Sat Oct 8 11:49:23 BST 2005 "
[12:26:36] <Jacky^> looking here: http://www.interq.or.jp/japan/se-inoue/e_link_to.htm
[12:27:05] <Jacky^> there are a lot of electrocis websites ..
[12:27:06] <alex_joni> Jacky^: what's that?
[12:27:37] <Jacky^> links to electronics sites ..
[12:27:42] <Jacky^> the best i found
[12:29:16] <Jacky^> http://www.uoguelph.ca/~antoon/gadgets/741/741.html
[12:31:59] <Jacky^> anonimasu: hope help you .. :(
[12:34:42] <alex_joni> anonimasu: gotta go :(
[12:34:46] <alex_joni> but this is what I would do
[12:35:09] <alex_joni> 1. get a proper +/-10V supply (either circuit or 9V battery :)
[12:35:23] <alex_joni> 2. invert the signal (input to V-, r1=r2, V+ to Gnd)
[12:35:43] <alex_joni> 3. sum the output with 5V and obtain the final result
[12:35:54] <alex_joni> you will need 2 opamps
[12:36:10] <alex_joni> or.. alternative approach :)
[12:36:24] <alex_joni> 1. get an ADS0808 convert the analog to digital 8 bit
[12:37:01] <alex_joni> 2. invert the signal in digital (subtract it from FFFF)
[12:37:21] <alex_joni> 3. use an R2R network (or an DAC) to generate the inverted analog signal
[12:37:25] <alex_joni> problem is resolution
[12:37:27] <alex_joni> ok.. later
[16:41:24] <alex_joni> hi dan_falck
[16:41:35] <dan_falck> hi alex
[16:41:51] <alex_joni> how've you been?
[16:41:56] <dan_falck> good
[16:42:02] <alex_joni> nice to hear that
[16:42:12] <dan_falck> I've been using my new milling machine
[16:42:18] <alex_joni> cool.. nice machine?
[16:42:27] <dan_falck> It doesn't have emc controlling it though
[16:42:36] <dan_falck> uses a Centroid control
[16:42:41] <alex_joni> well.. suppose that will come later ;)
[16:42:44] <dan_falck> yep
[16:42:55] <alex_joni> * alex_joni found a nice lathe
[16:43:07] <dan_falck> it does have a lot of nice features
[16:43:21] <dan_falck> how are you doing?
[16:43:36] <alex_joni> travelling a lot
[16:43:40] <alex_joni> but ok, otherwise
[16:47:15] <alex_joni> dan_falck: http://www.robcon.ro/emc/foo/Resize%20of%20HPIM9066.JPG
[16:49:05] <dan_falck> wow. that's very large
[16:49:14] <alex_joni> interested? it's for sale :D
[16:49:36] <dan_falck> it's a bit large for my little home shop
[16:49:40] <alex_joni> also pretty long too (I think up to 10-15m)
[16:49:45] <alex_joni> :)
[16:49:47] <dan_falck> wow
[16:50:01] <dan_falck> is it for working on sewer pipe or large pipeline?
[16:50:10] <alex_joni> no idea :D
[16:50:30] <dan_falck> I saw some like that being moved out of a place that did pipe work
[16:50:51] <dan_falck> they turned very slowly and howled with chatter
[16:51:12] <alex_joni> let me show you another nice machine
[16:51:16] <dan_falck> ok
[16:53:37] <alex_joni> uploading now (www.robcon.ro/emc/foo/big/ )
[16:54:14] <alex_joni> will probably take a while
[16:58:49] <dan_falck> so, alex, is this your home shop? ;)
[16:59:02] <alex_joni> nah.. a customer I worked with
[16:59:13] <dan_falck> looks like a truck could sit on the rotary table
[16:59:17] <alex_joni> darn, copied some files somewhere else
[16:59:25] <alex_joni> look under foo/ aswell
[16:59:30] <alex_joni> www.robcon.ro/emc/foo/
[17:02:01] <dan_falck> those are some big machines
[17:03:06] <alex_joni> pretty big :D
[17:04:00] <alex_joni> www.robcon.ro/emc/positioner/ <- that's what I usually do
[17:06:36] <dan_falck> nice
[17:08:25] <alex_joni> yup, I like it ;)
[17:08:50] <alex_joni> I always wondered if I could hook up an older robot to emc ;)
[17:08:56] <alex_joni> the old ones were DC-based
[17:09:22] <alex_joni> with encoders, so it would be easy to set them up using G340's
[17:12:02] <dan_falck> it's been good chatting alex, I need to go do breakfast.
[17:12:57] <alex_joni> enjoy
[17:15:11] <alex_joni> hey Jymmm
[17:15:44] <Jymmm> mornin
[17:16:02] <alex_joni> [18:40] <Jymmm> mornin
[17:16:04] <alex_joni> almost ;)
[17:16:16] <Jymmm> [08:41:02] <alex_joni> [18:40] <Jymmm> mornin
[17:16:44] <alex_joni> ok then ;)
[17:17:28] <Jymmm> oh man... I tried doing a 1" photo yesterday.... got 1/3rd done in 90 minutes and had to stop.
[17:17:43] <alex_joni> huh.. milling?
[17:17:53] <Jymmm> yeah
[17:18:00] <alex_joni> nice
[17:18:08] <Jymmm> not really =) lol
[17:18:43] <Jymmm> See, when I was looking at buying a laser engraver I learned quite a bit.
[17:19:30] <Jymmm> I took one of my hi-res photos in and had them laser engrave it. Turned out horrible
[17:20:09] <Jymmm> I had to test it out on my router at least and I thought the method would be different but it's not.
[17:20:28] <Jymmm> You don't use hi-res images - too much data in them.
[17:20:33] <alex_joni> right
[17:20:38] <alex_joni> need to downsample them
[17:20:49] <alex_joni> ideally convert them to BW
[17:20:51] <Jymmm> well, more than that...
[17:20:57] <Jymmm> they were B&W
[17:21:07] <alex_joni> B&W not grayscale I hope
[17:21:28] <Jymmm> well greyscale, b&W give you real crap
[17:21:51] <alex_joni> why's that?
[17:21:54] <Jymmm> but there are filters you need to use plus alter the contrast.
[17:22:01] <alex_joni> right
[17:22:30] <Jymmm> you want it a 'fluid transition' between items in the photo, using a blur filter will do this
[17:23:12] <Jymmm> it takes some finese with gimp/psp/ps/imagemagick but not hard to leran once you get the concept.
[17:23:33] <Jymmm> I was just hoping that this SW would do all that for me
[17:23:43] <Jymmm> I now know better =)
[17:24:55] <alex_joni> right
[17:25:30] <alex_joni> nice
[17:25:32] <Jymmm> In the laser world, there is even a special program just for engraving photos out there, and for one w/o any PS knowledge/skill it's fine, but the same thign can be done in any program.
[17:27:01] <Jymmm> Right now, I'm havign a harder time finding an 1/8" to 1/4" collect adapter and hardwood 1/4" thick
[17:29:41] <Jymmm> damn.... mahogany 1/4" thick 24" sq == $23 USD
[17:29:59] <alex_joni> hmm..
[17:30:18] <Jymmm> actually, almost all species are int he $20 range
[17:30:29] <alex_joni> get some dark cherry
[17:30:59] <Jymmm> it's the thickness (or thinness) that I can't find locally
[17:32:00] <alex_joni> I see
[17:32:45] <Jymmm> hawt damn... not local, but...
[17:32:52] <Jymmm> http://www.constantines.com/index.asp?PageAction=VIEWCATS&Category=130
[17:32:55] <Jymmm> brb
[17:40:30] <Jymmm> back
[17:40:49] <Jymmm> hey, did you see the switches I found?
[17:42:55] <Jymmm> alex_joni: limit/home or maybe even a probe ---> http://oeiwcs.omron.com/webapp/commerce/command/ProductDisplay?prrfnbr=387&prmenbr=316
[17:43:09] <Jymmm> about $30 USD
[17:49:33] <alex_joni> nice plungers
[18:03:39] <Jymmm> seem like it - would be cheaper than making a probe
[18:04:50] <alex_joni> * alex_joni goes away
[18:04:52] <alex_joni> later guys
[18:04:57] <Jymmm> hasta
[18:05:15] <les> hi jymmm
[18:05:22] <Jymmm> hey les!
[18:05:50] <les> just taking a break from mounting some chain hooks on the tractor bucket
[18:06:18] <Jymmm> chrome plated hooks I suspect =)
[18:06:30] <Jymmm> bling bling
[18:06:50] <les> Also started drawing up a new vacuum shroud/mount bracket for the colomo...it came yesterday.
[18:07:04] <Jymmm> ah, very cool
[18:07:24] <les> the old one just used 3" nylon bristles
[18:07:42] <Jymmm> did it work?
[18:07:56] <Jymmm> brb
[18:07:59] <les> this time I will mount the brush frame on thompson bearings so it can conform better to the work
[18:08:10] <les> there was some leakage before
[18:08:45] <les> with a very long bit the bristles did not reach the work surface
[18:10:17] <les> anyway it LOOKS like the cooling fan of the spindle needs to run on 240/60....so two separate power lines
[18:10:57] <les> main motor is 240 /0-400 delta or 380/0-400 wye
[18:11:14] <les> 3 phase
[18:11:59] <les> have to call to confirm
[18:12:40] <Jymmm> back
[18:13:10] <Jymmm> eeeesh, sounds like a wiring nightmare
[18:13:21] <les> just another line
[18:13:38] <les> a tiny 240/60
[18:13:41] <Jymmm> ah, ok.
[18:13:54] <les> it's just a little muffin fan
[18:14:18] <les> I also ought to switch the limit switch circuits from 5 to 24
[18:14:38] <Jymmm> les oh, check these out... http://oeiwcs.omron.com/webapp/commerce/command/ProductDisplay?prrfnbr=387&prmenbr=316
[18:14:43] <Jymmm> about $30
[18:14:46] <les> there may be some interference from the 5 kw vfd
[18:14:55] <les> looking
[18:15:25] <Jymmm> you might need to look at the datasheet to get a better idea
[18:16:34] <les> the switches are nice...but limit and such should always be normally closed
[18:16:38] <les> need spdt
[18:17:23] <les> with NC if the switch fails the control will know it as soon as you power up
[18:17:25] <Jymmm> ah
[18:17:37] <les> usually
[18:17:54] <les> switches usually fail open
[18:18:35] <les> well...72 degrees, 40% rh, no wind, no clouds
[18:18:40] <les> back outside!
[18:18:45] <Jymmm> c-ya
[18:18:50] <les> bbiaw
[18:45:32] <dmess> hi all
[19:18:59] <Jymmm> The lights are on, but nobody's home =)
[22:00:24] <K`zan> Anyone know if the HobbyCNC stuff works with "standard CNC" utilities like EMC, TurboCNC, things like that? Since they don't say so I assume it doesn't.
[22:01:15] <K`zan> And the only way you seem to be able to get a response from them is to buy one and then they will let you in their closed support forum. Sounds scammy to me, but I might be wrong...
[22:02:00] <cradek> yeah, that sounds like bad news.
[22:02:21] <cradek> emc provides step/dir outputs, it's a very standard interface for stepper drivers
[22:02:31] <cradek> (emc also has a few others)
[22:05:39] <K`zan> cradek: I gathered that much and I decided to go ahead and build my own cnc router out of what I can find. I got the machine for it and the steppers coming, all I need is a controller which I will eventually need anyway. Worst it can be is educational until I can save enough scratch for a real mill.
[22:06:01] <cradek> neat
[22:06:18] <cradek> I think building your own could be fun and definitely a learning experience
[22:07:00] <cradek> a lot of guys here seem to do that if they don't have something (a manual machine) to start with
[22:07:32] <K`zan> Maybe it will route PCBs and maybe it won't, but I will learn a LOT in the process that will pay off later. The big thing now is to resolve what controller I get.
[22:07:49] <cradek> do you want to build or buy that?
[22:08:19] <K`zan> Open to either, but I want one that works with standard CNC stuff.
[22:08:43] <K`zan> I can build, no problem (primary here is microcontoller apps).
[22:09:04] <cradek> you won't go wrong with step/dir then.
[22:09:35] <cradek> for any kind of performance you need choppers that run at a relatively high voltage
[22:09:52] <K`zan> The stepper I have coming are:
[22:09:55] <cradek> you need half stepping, microstepping is nice but not at all necessary.
[22:10:16] <K`zan> http://www.goldmine-elec-products.com/prodinfo.asp?number=G14781&variation=&aitem=3&mitem=6
[22:10:57] <K`zan> I wrote up a stepper controller using an AVR micro, works well enough on that stepper I stripped out of a windoz only scanner.
[22:11:04] <cradek> how small/light a machine are you making? Those are awfully small.
[22:11:17] <K`zan> Interesting. Hard part was figuring out and identifying the windings :).
[22:11:48] <cradek> what did you use to drive it? Just transistors switching 12v?
[22:12:00] <K`zan> Probably very small / light - idea is to do PCBs probably no bigger than 12x12"., if that.
[22:12:13] <K`zan> Used a ULN2803
[22:12:22] <cradek> just 12v, no ballast resistors?
[22:12:29] <K`zan> We use that in our anamatronics controller.
[22:12:43] <cradek> I assume that's just a low side transistor switch of some kind
[22:12:51] <K`zan> Yes, just 12V. Very ignorant of much here.
[22:13:09] <K`zan> Darlington setup, 8 of them in a DIP18
[22:13:58] <cradek> you will get little torque driving a stepper like that, but it sure is easy for a first shot
[22:14:52] <K`zan> That was my thought and the price was right too. NEI what kind of torqe that has, can't be much - no info I could find wading through google.
[22:15:37] <K`zan> By the time I replace those I will have a better idea of what I need. It seems to have more orless the same tech specs as the $50+ ones outside of torque.
[22:15:49] <cradek> any idea what you'll use for leadscrews?
[22:16:17] <K`zan> Heh, no idea what ballast resistors would be for, no floro lamps on it ;-).
[22:16:50] <cradek> the idea is to use 4-5x the voltage of the motor and burn the excess in big resistors in the steady state
[22:16:51] <K`zan> Whatever they have down at Home Depot to start with, will be coarse, of that I am sure.
[22:17:11] <K`zan> Ah, sorta like caps but difference more or less LOL
[22:17:16] <cradek> the coils of your motor are inductors
[22:17:22] <K`zan> Yes
[22:17:27] <cradek> so when you increase your voltage, the time constant goes down
[22:17:40] <icee> in resistors?
[22:17:41] <K`zan> Buffering it
[22:18:04] <cradek> the resistors keep the motor from burning up in the steady state (some coils on, not moving)
[22:18:07] <icee> the idea with a chopper drive is to turn transistors on and off-- modulating current like a dc-dc converter does
[22:18:26] <K`zan> PWM essentially ?!?
[22:18:40] <cradek> yes, a chopper does away with the ballast resistors and keeps the average current down to the rated value using the inductance of the motor
[22:18:55] <icee> kz: sure, sort of.
[22:19:08] <icee> You turn the high side transistor on until you reach the desired current, then turn it off
[22:19:29] <icee> then the current instead flows through the diodes you have (or the body diodes in the fets, or whatever, and decays)
[22:19:36] <icee> after a specified 'off time', you turn on again.
[22:20:51] <K`zan> So far, my thinking is that I should first off purchase a commercial controller assuming it is affordable. Once I know something I can build my own once I have a finer understanding of all that goes on.
[22:21:16] <cradek> unless you have parts already, a commercial controller will probably be cheaper.
[22:21:16] <icee> kz: not insane. I'm building my own controller, but I don't expect huge cost savings in doing so
[22:21:20] <K`zan> Screwing around with large forces can get expensive in the development phase :-)
[22:21:47] <K`zan> icee: Affordable depends on more than just rad $$$.
[22:22:07] <K`zan> S/RAD/RAW
[22:22:33] <icee> kz: yah, there's opportunity cost ;P
[22:23:43] <K`zan> :-) too true.
[22:24:45] <K`zan> Was/am considering two, not sure which is really better, The HobbyCNC one is cheap enough but no idea what it works with. Outfit seems not too interested (or afraid?) to give out much info.
[22:25:03] <K`zan> Option2 is that I may be too ignorant at this point to understand it :-(.
[22:25:35] <cradek> K`zan: sometimes you can figure out the output driver chip and examine the datasheet for it
[22:25:59] <cradek> the input is virtually always going to be step/dir
[22:27:24] <K`zan> http://xylotex.com/ is the other one under consideration, almost twice the price but is it worth it ?!?
[22:27:34] <K`zan> Or is the hobbycnc one even a contender ?!?
[22:27:37] <K`zan> Sigh...
[22:27:58] <cradek> I know the xylotex are relatively popular
[22:28:09] <cradek> but I'm suspicious that the heat sinking on them is improper
[22:28:20] <K`zan> cradek: You can see what I am putzing with: http://wrlabs.shacknet.nu/~vw/CNC/
[22:28:23] <cradek> also they seem easy to blow up (one overvoltage spike and it's dead)
[22:28:59] <K`zan> Yes, I have noticed some dissention about those. What are other good options ?
[22:29:04] <cradek> You don't have permission to access /~vw/CNC/MotorTestJig1.jpeg on this server.
[22:29:23] <K`zan> Bear in mind the last time I was involved in CNC was running an ancient Moog :-).
[22:29:32] <K`zan> lemme check.
[22:30:59] <K`zan> try it now
[22:31:10] <cradek> aha
[22:31:11] <K`zan> VERY basic
[22:31:32] <cradek> ok, you have a unipolar motor
[22:31:43] <K`zan> Yes Sir, 5 wire
[22:31:44] <cradek> you will get more torque from the same size motor if you run it bipolar
[22:31:59] <cradek> but that makes the driver much more complex
[22:32:25] <K`zan> Something I stripped out of a windoz only scanner, if it only worked under winditz, the only thing good about it was the stepper ;-)
[22:32:49] <K`zan> cradek: Yes, I knew even less than I do now (if you can imagine that :-) when I did that.
[22:32:58] <cradek> I wonder if sherline sells their driver box only
[22:33:08] <cradek> (their website is terrible)
[22:33:09] <K`zan> It is cute in that it waves a few flags on the gears :)
[22:33:13] <K`zan> Yes, it is.
[22:33:39] <cradek> oh that's new - it chides me about not using IE
[22:33:57] <cradek> and then it gives me a big black rectangle
[22:34:07] <K`zan> cradek: It was that bit of experimentation that lead me to be seriously considering a commercial offering for a controller.
[22:34:25] <K`zan> If the site has to have IE, then just flat (pardon) fuck 'em.
[22:34:33] <K`zan> ANY site :-).
[22:34:46] <cradek> http://www.sherline.com/8760pg.htm
[22:35:01] <K`zan> Becoming less and less fond of m$centric anything anymore.
[22:35:22] <cradek> me: choir; you: preaching
[22:35:56] <cradek> can't spot a price here though, it's somewhere else
[22:37:18] <K`zan> Yeah, that site is about a kunky as I have seen.
[22:37:44] <K`zan> Apparently have to keep downloading .PDFs until you find that item.
[22:37:58] <cradek> there's a price list somewhere there - I've seen it
[22:38:19] <K`zan> .htm is always a big red flag :-)
[22:38:25] <K`zan> searching...
[22:40:45] <K`zan> $600 for a controller, a box, power supply and cables - Hahahahahahahaha, righteo.
[22:40:51] <K`zan> NOT
[22:41:50] <K`zan> box, power supplies and cables I got :-).
[22:41:57] <cradek> ouch
[22:42:32] <K`zan> Sherline has always looked cheesy and too damned expensive to me...
[22:43:02] <cradek> I think their stuff is actually really good. I have several of their machines.
[22:43:12] <cradek> of course it's *small*
[22:43:14] <cradek> but that's the idea
[22:43:32] <K`zan> http://www.taigtools.com/index.html
[22:43:50] <cradek> the cadillac of stepper drivers is gecko, but they are more expensive
[22:43:56] <K`zan> Is what I am shooting for at this point, unless someone drops off a free Bridgeport clone.
[22:43:57] <cradek> however, you won't have to buy bigger ones later.
[22:44:15] <K`zan> cradek: I think I saw that one and was going to go back to it lemme check
[22:44:16] <cradek> but the gecko website is currently broken!
[22:44:36] <cradek> I think the taig is a good starting point
[22:44:44] <K`zan> I can just imagine what kind of mess the net would be with the UN running it :-).
[22:45:08] <cradek> I started with a maxnc, but the taig is probably a better mill to start with
[22:45:29] <cradek> if I could buy a maxnc without spindle motor or control box (but with their steppers mounted) I might be tempted to start with that.
[22:45:39] <cradek> their controllers suck, their spindle motors suck, their software sucks
[22:45:55] <cradek> but the basic mill itself is fine and inexpensive.
[22:46:50] <cradek> yeah, I think a maxnc will start at half this price
[22:46:55] <cradek> (but it's probably half as good)
[22:47:26] <cradek> for pcb only, maybe you could get by with the dremel model
[22:47:29] <cradek> (maxnc 5)
[22:47:58] <cradek> if you could talk them into giving it to you for $995 - drivers - software = $??
[22:50:06] <K`zan> Looking for a link to that now.
[22:50:34] <cradek> http://maxnc.com/page11.html
[22:50:36] <cradek> (sorry)
[22:51:18] <K`zan> Tnx! Np
[22:51:19] <cradek> my machine is about this size and I do 4x6" PCBs on it
[22:51:56] <K`zan> Not that much less expensive than the Taig with CNC updates.
[22:52:14] <cradek> I saw the taig starting at $2100 - did I miss something?
[22:52:19] <K`zan> Which would be a lot more capable.
[22:52:31] <cradek> yeah.
[22:53:04] <K`zan> IIRC it was about $1200, lemme check, been looking at an awful lot of stuff here over the past few days, being confused at this point isn't out of the question :-).
[22:54:01] <K`zan> Basic mill: http://www.taigtools.com/mmill.html $650 up
[22:54:35] <cradek> huh
[22:54:39] <cradek> yeah that's a much better machine.
[22:55:26] <K`zan> 2019CR-ER
[22:55:48] <K`zan> That is what the pennies are being dumped in the milk jug for :-).
[22:56:02] <cradek> wonder what NEMA23 bipolar motors will cost you
[22:56:34] <K`zan> Wonder what the gekko controller goes for, I'm sure someone will figure out they haven't paid the m$ tool use tax and fix it in time for me to make a decision.
[22:56:48] <K`zan> Why do people use m$ centric crap like that, sigh.
[22:56:57] <cradek> I think the geckos are $100-$150 per axis
[22:57:08] <cradek> I think they handle 70 volts (!!)
[22:57:13] <K`zan> Prices on the motors seem to be about $50-$55 from what I have seen,
[22:57:20] <K`zan> each
[22:57:28] <cradek> I understand they are the last drivers you will ever buy.
[22:57:50] <cradek> in fact, I've heard that even if you buy something else first, geckos are STILL the last drivers you will ever buy.
[22:58:23] <cradek> unfortunately that was too much cash for me, so I built my own though.
[22:58:25] <K`zan> THat may well make it worth it then. Still, assuming something like the hobbycnc would workd with standard CNC stuff, it might be worth it for the education in the process while the milk jug fills :-)
[22:58:34] <K`zan> LOL
[22:59:17] <cradek> I'm happy with the drivers I built, however, and I paid maybe $100 total for 3 axes
[22:59:48] <cradek> I have a *large* "junkbox" that contained most of the necessary parts.
[23:00:14] <K`zan> About the price of the hobbycnc
[23:00:26] <cradek> I better get back to work on my garage
[23:00:35] <K`zan> My junkbox in an apartment has been severely paired down :).
[23:00:43] <K`zan> Appreciate the chat / education MUCH.
[23:00:44] <cradek> in warm weather it morphs into a shop, but when the cold weather comes I have to convert it back to a garage
[23:00:55] <K`zan> I got to get in and finish the copy stand I am building too.
[23:01:03] <cradek> you're welcome
[23:01:06] <K`zan> Again, THANKS es catch ya later.
[23:02:03] <K`zan> Heh, make that a half hour later, Router Workshop is on PBS here :)
[23:04:04] <ValarQ> 'lo joni
[23:04:11] <alex_joni> 'lo
[23:04:53] <alex_joni> what's up doc?
[23:06:14] <ValarQ> who is the doctor?
[23:06:54] <alex_joni> no idea
[23:06:55] <alex_joni> :D
[23:07:56] <ValarQ> ok...