#garfield Logs
Nov 21 2020
#garfield Calendar
12:31 AM rue_shop1: the other option of course, is to integrate a square wave before it goes into the transformer :)
12:37 AM rue_shop1: its working rather well
12:58 AM rue_shop1: ok, the signal looks like a mess unless you can see the 20us S&H window
02:46 AM rue_mohr: morning pokl
02:46 AM rue_mohr: morning polprog
02:49 AM polprog: morning rue :)
02:49 AM rue_mohr: so, right now,
02:49 AM rue_mohr: I'm not so sure why lvdt circuits are so complex
02:49 AM rue_mohr: all that sinewave junk?
02:50 AM polprog: breakfast and work
02:50 AM polprog: 4 hours :(
02:50 AM polprog: then mech, maybe, then ee
02:50 AM polprog: maybe :/
02:51 AM rue_mohr: this worked really good so far
02:52 AM rue_mohr: 0-5V over 0.2"
03:02 AM rue_bed: I think I can use the ldvt primary, trifillar wound, for power
03:02 AM rue_bed: and clamp the other windings to limit the ramp rate
03:42 AM polprog: sounds good
03:42 AM polprog: i have to take a look at the schematic :)
03:42 AM polprog: classes start
10:59 AM rue_bed: wow its saturday
11:09 AM TermMoon: wow
11:09 AM rue_mohr: https://twitter.com/TechAmazing/status/1329835186226421764
11:11 AM TermMoon: text only babe
11:12 AM rue_mohr: I'm bookmarking it for me, thats awesome
11:27 AM Tom_L: good morning
11:28 AM rue_mohr: mmm
11:28 AM Tom_L: sry but i wouldn't really wanna shake hands with him
12:31 PM aandrew: yep. it's saturday. I cut down all the cardboard and am going to make a dump run. son has some young artist awards he's gotta be a part of, don't think he'll win anything this year
12:32 PM aandrew: rue_mohr: I'm still not sure why you prefer triangle wave to sine
12:32 PM aandrew: I don't see the advantage
12:36 PM Tom_L: you grow cardboard?
12:49 PM rue_mohr: aandrew, the advantage is that the output of the lvdt is then a square wave, which is easier to process a static value from
12:51 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180082.jpg
12:51 PM rue_mohr: there is a great 20us window where its just a dc value
12:52 PM rue_mohr: I could grab it with an avr, or use a discrete s&h and take a few channels into a transmitter
12:54 PM rue_mohr: I wonder if a channel of a GAL can be used to make an RC oscillator that clocks itself with enough pins left over for a small state machine
12:55 PM rue_mohr: I can use a 555 for a lot of this, but doing the sample and hold timing is still something I'm not sure of a method on.
12:55 PM rue_mohr: my plan is to use a falling edge delay from the square wave
12:55 PM rue_mohr: er, rising
12:57 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/LVDTdrv.png
12:57 PM rue_mohr: the other part looks flatter, but thats just cause it hit the rail :)
01:23 PM polprog: hmm, nice
01:23 PM polprog: yeah you can do a gal RC osc
01:43 PM rue_mohr: I'm sure it would need a jumper from the osc output to the clk input, but whatever
03:05 PM aandrew: rue_mohr: ah ok, I see why you're doing that now, although that's just software laziness. :-)
03:19 PM rue_mohr: accept for hardwae
03:54 PM polprog: ah yeah if you do registered...
03:54 PM polprog: wait no, i think each olmc can be different mode
03:55 PM polprog: i made a ring osc outta 3 OLMCs then you can make a RC osc out of one
03:55 PM polprog: Q = /Y :)
03:55 PM rue_mohr: oh yea
03:55 PM rue_mohr: you did a ring osc didn't ya?
03:59 PM polprog: yep
03:59 PM polprog: oh crap. i just had an epiphany watching a video
04:00 PM polprog: you know how ADSL runs 8-24 MBps over phone line right>
04:00 PM polprog: ?
04:00 PM polprog: it splits that into channels between 25k and 1M or 2.2Mhz depending on version
04:01 PM polprog: do you know how much a single channel can transmit?
04:01 PM polprog: take a guess
04:05 PM polprog: ah nvm
04:05 PM polprog: i think the guy made a mistake
04:05 PM polprog: he said each channel is 56k but other sources say its 64k
04:09 PM rue_shop2: hmm, didn't studdy it much, I did make a 'DSL' detector for work, it looks for the high freq carrier
04:09 PM rue_shop2: so, only enough to make a filter for detection
04:17 PM rue_shop2: just tried to rotate my 2d drawing in 3d space
04:18 PM rue_shop2: :)
04:19 PM Tom_L: how'd that go?
04:20 PM Tom_L: ya know, all ya gotta do is give it a tiny bit of depth and you can
04:20 PM Tom_L: that's how i import those dxf files
04:30 PM rue_shop2: yea, I take the 2d files into openscad and extrude them
04:30 PM rue_shop2: iirc the new programs have different windows for modifying your 2d sketches and the 3d stuffs
04:31 PM rue_shop1: to test my new ideas, I need to make another spool with a trifillar primary
04:31 PM rue_shop1: I'd also like to add a few hundred more turns to the secondaries
06:11 PM polprog: hmm, i think i played with ajunk SHDSL modem but all i got was some beeps on the phone
06:11 PM polprog: SHDSL uses the whole spectrum iirc
06:11 PM polprog: it had a nice atmega inside too, i think
06:26 PM rue_shop1: ok
07:49 PM aandrew: yes it does
07:50 PM aandrew: I set up SDSL links all over town as one of the first businesses I set up
07:51 PM aandrew: bell wanted my left nut for real connectivity but I designed a satellite downlink + bonded 4x33k6 uplink to Waterloo here, and that started things off
07:51 PM aandrew: that's when I learned GVC didn't understand the PnP spec
07:52 PM aandrew: any one modem in the system - no problem
07:52 PM aandrew: 2+ modems: none detected
07:53 PM aandrew: I had read the spec quickly, learned that the PnP EEPROM stores settings and one of them is serial number, and if you don't wish to serilaize your devices you were supposed to make the serial number -1, not 1
07:53 PM aandrew: so I pulled them off, reprogrammed them, put them back in and we had our uplink
07:53 PM aandrew: after that we did buy a T1, and I learned Cisco iOS by being thrown in the deep end (getting the samned AS5248 to work)
07:54 PM aandrew: and selling SDSL links to businesses
07:54 PM aandrew: Megabit Modem 300S IIRC
07:55 PM aandrew: then later a little copper mountain SDSL head-end which I still have in my garage
07:55 PM aandrew: the trick with SDSL links was you had to order dry pairs from Bell; they charged you $x/km and to maximize your reach, you wanted your head end as close to the CO as possible
07:55 PM aandrew: friend of a friend had a comic book shop that was literally 500' away, so we took over one of his closets
07:56 PM aandrew: then Bell started playing fuck around and would not guarantee that the coils on the line would be cut
07:57 PM aandrew: luckily we knew most of the line techs and they were nice
08:26 PM rue_shop1: damn they needed 37 lamacoids at work and its taken me all freaking day
08:28 PM aandrew: hm?
08:28 PM Tom_L: you machining them?
08:29 PM aandrew: what do they look like?
08:30 PM Tom_L: dog tags
08:30 PM Tom_L: ?
08:35 PM rue_shop1: yea
08:35 PM rue_shop1: _37_
08:35 PM rue_shop1: I'll take a pic
08:36 PM rue_shop1: I'm trying to keep up with the machine just now
08:41 PM Tom_L: you doing the lettering or just the profile?
08:42 PM rue_shop1: lettering and profile
08:42 PM rue_shop1: and holes in some
08:43 PM Tom_L: what are they using em for?
08:50 PM rue_shop1: done 21 nc files so far
08:50 PM rue_shop1: electrical room labels
08:50 PM Tom_L: what are you using for the txt?
08:52 PM aandrew: interesting
08:52 PM aandrew: didn't you have a machine that was punching those out into plastic cards?
08:53 PM rue_shop1: hah
08:53 PM rue_shop1: no the equipment labels need to be cut plastic
08:54 PM Tom_L: where you gettin the laminated plastic blanks?
08:59 PM aandrew: so... my concrete box failed
08:59 PM aandrew: not unexpected, but some unexpected failure modes
09:09 PM rue_shop1: Tom_L, sheets
09:10 PM rue_shop1: 24" x 48"
09:10 PM rue_shop1: the local guys who could do lamacoids were hopeless
09:12 PM Tom_L: really? why?
09:14 PM aandrew: rue_shop1: how are you making them?
09:14 PM aandrew: CNC?
09:14 PM rue_shop1: yup
09:14 PM aandrew: nice
09:14 PM rue_shop1: the guy at work was going to spend $20000 on a machine
09:14 PM aandrew: damn
09:14 PM rue_shop1: I was like "uh, no dude"
09:14 PM Tom_L: heh
09:15 PM aandrew: so you told him you could do it for $15k right?
09:15 PM Tom_L: we could build a fleet for that
09:15 PM rue_shop1: haha
09:15 PM rue_shop1: I pointed out that the $100 china machine could do them no problem
09:15 PM aandrew: which CNC is that one?
09:15 PM aandrew: I might have to franchise out here in Ontairo
09:31 PM rue_shop1: oh any of the sad looking ones from china with the 3d printed angle brackets and carriages
09:31 PM rue_shop1: the plastic is really easy to cut
09:32 PM Tom_L: you using an endmill or V point?
09:34 PM rue_shop1: square, I dont have a proper V
09:34 PM rue_shop1: I should get a flat-end V
09:34 PM rue_shop1: well, I'll make them get me one at work
09:34 PM rue_shop1: and a liscence for the software I'm using }:/
09:34 PM rue_shop1: cause the free version sucks
09:34 PM Tom_L: what is it?
09:35 PM Tom_L: how big are the tags?
09:46 PM rue_shop1: crap jogged the wrong way and lost a bit
09:46 PM Tom_L: what feed/speed are you using?
09:47 PM Tom_L: https://www.amazon.com/Engraving-3-175mm-Carbide-High-precision-Aluminum/dp/B00QNIXAOQ/ref=psdc_686957011_t2_B019K5G6AI
09:48 PM Tom_L: i've got similar to those
09:48 PM Tom_L: pack of 10 from china
09:48 PM Tom_L: you can find them with a larger tip diameter
09:50 PM Tom_L: https://www.ebay.com/itm/10-x-V-shape-Carbide-PCB-0-1mm-60-Degree-Engraving-Bits-CNC-Router-Tool-Set/174341847146?hash=item289795786a:g:nhEAAOSwpbxfBUxq
09:57 PM rue_shop1: most of them about about 1.5 x 4"
09:58 PM rue_shop1: I'm running at 300mm/min for the engrave and 200mm/m on the cut
09:58 PM rue_shop1: prolly about 6500 rpm
09:58 PM rue_shop1: 1.6mm bit
09:58 PM rue_shop1: engrave is 0.2mm deep
09:59 PM rue_shop1: cut is 2.2mm (lots of overcut
10:00 PM Tom_L: hmm bigger than i'd expected
10:01 PM Tom_L: need some pics :)
10:19 PM rue_shop1: I'm just in the race to get this out of my way
10:26 PM rue_shop1: ok, done the 25th nc file
10:26 PM rue_shop1: 2nd to last one cutting now
10:27 PM Tom_L: does the program center the txt for you?
10:37 PM rue_shop1: hah no
10:37 PM rue_shop1: I made a tempate with guides
10:43 PM rue_shop1: looks like only 3 redos