#garfield Logs
Mar 06 2021
#garfield Calendar
03:13 AM polprog: rue_mohr: what are stabilzing amplifiers
06:58 AM aandrew: yeah I went to bed at 4am on thursday (well friday morning), I was surprisingly not too out of sorts despite waking up at 8am on Friday, but did crash around 8pm and didn't move until 6am
10:57 AM rue_bed: oh yea
10:57 AM rue_bed: I want to make an unstable op-amp setup and then stabalize it
10:58 AM rue_bed: I have some things to try that I'v read
10:59 AM Tom_L: so you start out bad and make it better. start out good and make it fabulous!!
11:00 AM rue_bed: I"m always having problems with op-amp things being unstable
11:00 AM rue_bed: so I was looking up how to fix things
11:00 AM rue_bed: and there are some odd things I want to try
11:02 AM rue_bed: arg, got about 5 tones going in my ears right now
11:02 AM rue_bed: I used to only be able to hear it if I focused
11:05 AM rue_bed: 9am
11:05 AM rue_bed: ugh
11:06 AM rue_bed: ok might as well get up then
11:08 AM rue_bed: so, jester moved to prince rupert
11:08 AM rue_bed: but
11:08 AM rue_bed: I have a pile of his stuff
11:08 AM rue_bed: ugh
11:12 AM Tom_L: how far is that?
11:21 AM aandrew: rue_bed: just get a nice super high impedance opamp and put it on a breadboard
01:32 PM rue_mohr: https://www.youtube.com/watch?v=l665eovBlEk 8-| oh my
01:33 PM rue_mohr: just lead, and sulfuric acid, no big deal..
01:34 PM rue_mohr: cool tab crafting tho
01:43 PM rue_mohr: interesting plastic welding too
01:43 PM rue_mohr: that might be acrylic
02:06 PM polprog: i found a book on numerical methods today
02:06 PM polprog: it features a part on FFT
02:09 PM polprog: there's a Cooley, Lewis, Welch FFT algorhitm in fortran
02:09 PM polprog: https://i.ibb.co/nkJzk95/IMG-20210306-205109.jpg
02:21 PM aandrew: oh ffs
02:22 PM aandrew: adafruit trinkets don't work with usb3 ports, the bootloader (software usb) fails to be detected. solution is to use a usb-2 port or put a usb-2 hub in the way
02:22 PM aandrew: unfortunately I don't have one of those in the car
02:41 PM rue_mohr: usb isn't backwards compat?
02:41 PM rue_mohr: polprog, interesting
02:41 PM rue_mohr: was cooleys the fastest?
02:42 PM rue_mohr: my fft uses an optimized lookup table
02:43 PM rue_mohr: only the values used in the calculations are in the table
02:43 PM rue_mohr: I think you will find that most tables include a set of values at she highest resolution they could deal with
02:43 PM rue_mohr: and when you get down to it, only a few of them are ever used
02:44 PM rue_mohr: I didn't overlap the cos/sin into one table
02:47 PM rue_mohr: polprog, I think cooleys contribution was the way the loop was itterated
02:47 PM rue_mohr: but you have to keep in mind they were doing it with a language that had no binary operators
02:48 PM polprog: aandrew: i had issues with usb3 on my laptop recently (it wouldnt detect a usb3.0 hdd) but it worked over a dumb usb2.0 extender
02:48 PM rue_mohr: so the cooley-tukey is a fantastic dance around the technology limitations
02:48 PM polprog: hmm
02:49 PM rue_mohr: nonally the lack of binary operators, but there being a limit to a single, 1D data array
02:49 PM rue_mohr: which is why they interlaced the values
02:50 PM rue_mohr: any modern code you see interlacing the values is doing it cause its a copy of that old code, that was just regurgitated cause the person didn't understand what it was doing
02:50 PM polprog: oh, i didnt know that
03:19 PM aandrew: rue_mohr: it is, but I guess there's a timing issue in the v-usb stack that breaks usb3 detection
03:19 PM aandrew: worked perfectly fine with a usb 3.0 hub in usb 2.0 mode
03:19 PM aandrew: (i.e. the upstream cable was just a 2.0hs not 3.0ss cable)
03:21 PM aandrew: I don't pretend to understand fft
03:32 PM polprog: i know the maths behind it, but i couldnt implement that in an optimal way in a program for my life
03:32 PM polprog: i did write an implmentation in C++ two semesters ago though, so maybe that would be a good starting point
03:32 PM polprog: i should throw it on STM32 and test the speed
03:37 PM rue_shop2: the hp encoders are apparently sine output
03:37 PM polprog: what encoders?
03:38 PM polprog: hmm it would be interesting to collect the fft algos (i have like 4 now) and test their speeds on stm32/m8
03:38 PM rue_shop2: mine will win
03:38 PM rue_shop2: :)
03:39 PM rue_shop2: by how much depends how you do the square-root :S
03:39 PM rue_shop2: I did a bad approx
04:02 PM polprog: :)
04:03 PM polprog: i have to do electrodynamics, english and german homework on monday
04:03 PM polprog: maybe ill do these today
04:03 PM polprog: and have a free sunday \o/
04:04 PM Tom_L: so why all the sudden doesn't this pc wake on mouse movement?
04:04 PM Tom_L: or kbd for that matter
04:04 PM Tom_L: i removed a logitech mouse driver to try
04:04 PM rue_mohr: is it windows
04:04 PM rue_mohr: did an update?
04:04 PM Tom_L: no i don't do updates
04:04 PM Tom_L: but i did realize i don't have a logitech mouse on this one
04:04 PM rue_mohr: 10 does its own
04:05 PM Tom_L: 7
04:05 PM Tom_L: i can't count past 7
04:05 PM rue_mohr: hm
04:05 PM Tom_L: it may have been that driver
04:06 PM Tom_L: the monitor didn't detect any video after it went to sleep on mouse or kbd
04:06 PM Tom_L: hope it ain't something on the MB going
04:08 PM Tom_L: your boss see the cap yet?
04:13 PM rue_mohr: he hasn't been at the shop much
05:22 PM Tom_L: ok so that wasn't the problem
05:22 PM Tom_L: any ideas?
05:29 PM Tom_L: ok let's try that
05:29 PM Tom_L: turned off all 'saver' modes
05:33 PM rue_shop1: yea
05:34 PM Tom_L: i was checking to see if the monitor itself had a timeout on it
05:34 PM Tom_L: it never did this until just recently
05:34 PM Tom_L: dunno what changed
05:35 PM Tom_L: kbd or mouse wouldn't revive it
05:35 PM Tom_L: maybe a bios battery?
05:35 PM rue_shop1: you mean it will turn on, just not with mouse or keyaord?
05:35 PM Tom_L: i looked there but didn't see any 'wakeup' options
05:36 PM Tom_L: the pc stays on, just no video
05:36 PM Tom_L: won't wake up after it goes to sleep
05:36 PM Tom_L: it's a wired mouse too
05:36 PM Tom_L: and kbd
05:36 PM rue_shop1: ah sleep of death
05:36 PM rue_shop1: dell?
05:37 PM Tom_L: no
05:37 PM Tom_L: i forget what MB it is, one i built
05:38 PM Tom_L: asrock q1900b-itx
05:38 PM rue_shop1: you dint' update thebios latley did you?
05:38 PM Tom_L: never
05:38 PM rue_shop1: huh
05:38 PM rue_shop1: I had a laptop that did it
05:39 PM rue_shop1: windows/bios problem
05:39 PM Tom_L: i just hate to leave the screen on all the time
05:39 PM rue_shop1: it takes about 43ms for the motor to settle
05:40 PM rue_shop1: just turn its power switch off
05:40 PM rue_shop1: better for it anyhow
05:40 PM Tom_L: yeah
05:40 PM Tom_L: i generally do that anyway
05:40 PM Tom_L: but if i'm in and out i leave it on
05:40 PM Tom_L: about all this one does is irc related
05:41 PM Tom_L: like summer out today
05:45 PM Tom_L: so what's goin on today?
05:46 PM rue_mohr: testing stepper mtoor
05:46 PM rue_mohr: takes 43ms after a step to finish settling
05:46 PM rue_mohr: looks like it changes diection 7 times
05:46 PM Tom_L: how you testing it?
05:49 PM Tom_itx: ok so that didn't fix it
05:49 PM Tom_itx: it locked up mid typing this time
05:49 PM rue_mohr: I made a stepper/encoder jig
05:50 PM rue_mohr: the machine locked while you were using it?
05:50 PM rue_mohr: bad caps
05:50 PM Tom_itx: had to reboot again
05:50 PM Tom_itx: shouldn't be that old
05:50 PM rue_mohr: remove side, observe bad caps
05:51 PM Tom_itx: swelled up?
05:51 PM Tom_itx: leaking..
05:52 PM rue_mohr: yup
05:54 PM Tom_itx: they're gonna be smt i bet
05:54 PM rue_mohr: no
05:54 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180799.jpg
05:54 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180800.jpg
05:54 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180801.jpg
05:54 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180802.jpg
05:54 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180803.jpg
05:54 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180804.jpg
05:54 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180805.jpg
05:54 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180807.jpg
05:54 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180808.jpg
05:55 PM rue_mohr: I started it last night when I got all energetic
05:56 PM Tom_itx: what's the disk?
05:56 PM rue_mohr: HP printer encoder
05:56 PM Tom_itx: that's big
05:56 PM rue_mohr: yup
05:56 PM rue_mohr: 1800 lines
05:56 PM Tom_itx: office printer?
05:57 PM rue_mohr: home inkjet
05:57 PM Tom_itx: wow
05:57 PM Tom_itx: never would have figured
05:57 PM rue_mohr: thats what they went to when the stopped putting encoders on the back of the motors like we used to play with
05:57 PM rue_mohr: and linear strips
05:59 PM Tom_itx: i've seen linear strips but no disk
06:05 PM rue_shop1: at about 2.5ms it was passing its target
06:06 PM Tom_L: caps all look fine
06:06 PM Tom_L: changed the bios battery while i was in there
06:06 PM Tom_L: reseated the ram etc
06:06 PM rue_shop1: the shaft took about 0.3ms to start moving after the coils were changed
06:10 PM Tom_L: now no video signal
06:10 PM Tom_L: maybe the psu is going
06:10 PM Tom_L: no hdd activity
06:16 PM Tom_L: ok try again. just blew it all out but it wasn't that bad. it's fanless
06:22 PM rue_shop1: hmm
06:22 PM rue_shop1: hopefull its not a bga
06:22 PM Tom_L: trying another psu
06:22 PM Tom_L: nothing
06:22 PM rue_shop1: :/
06:23 PM Tom_L: any ideas?
06:23 PM aandrew: rue_shop1: would you be interested in hosting your images on my server? We can even do a bit of URL magic so it's always ruemohr.org or cdn.ruemohr.org so it's not pointed off your domain
06:23 PM aandrew: it just really sucks that you (and Tom_L) post such low res images
06:24 PM aandrew: I'm happy to host it, I've got bandwidth to spare
06:24 PM Tom_L: i shrink mine
06:24 PM Tom_L: i got space but try to be kind to others
06:25 PM aandrew: MOAR BITS. MOAR PICKCELLS
06:26 PM aandrew: you guys do a lot of really cool shit it's a pity we can't see the flecks of rust or drill scars on it all
06:26 PM * polprog slaps aandrew with a 6000x4000 CR2 image
06:26 PM aandrew: bring it :-)
06:27 PM polprog: :P i usually scale mine to HD jpegs and thats enough :P
06:27 PM rue_mohr: lots of times there is no point in higher res
06:28 PM polprog: cdn.ruemohr.org sounds pretty amazing though
06:28 PM rue_mohr: I take the occasional thing that needs the detail and leave it higher
06:29 PM aandrew: rue_mohr: speaking as someone vicariously living thorugh what you're doing: you're not leaving nearly anything high enough res. :-)
06:29 PM rue_mohr: there is really nothing more to see tho :)
06:30 PM rue_mohr: if you have a question, but all means shoot it to me!
06:30 PM Tom_L: ok this really pisses me off
06:31 PM Tom_L: now the mb won't come up
06:31 PM Tom_L: good power on 5 & 12
06:31 PM rue_mohr: hmmm
06:31 PM rue_mohr: it kinda went down slow
06:31 PM Tom_L: tried 2 psu & 2 hdd
06:31 PM rue_mohr: is it warm or cold right now (the cpu)
06:31 PM Tom_L: kinda went down fast
06:31 PM Tom_L: cold
06:32 PM Tom_L: just cleaned it out
06:32 PM rue_mohr: hmmm
06:32 PM rue_mohr: its not turning on tho?
06:32 PM Tom_L: in a bit i'm gonna take it out of the box and try to boot it again
06:47 PM polprog: goodnight
06:47 PM rue_mohr: gnight
06:53 PM * Tom_L gives polprog a teddybear
07:03 PM Tom_L: all the voltages are on the psu
07:03 PM Tom_L: no bios no nuthin
07:04 PM Tom_L: no caps or chips look bad
07:04 PM Tom_L: looks very normal
07:04 PM Tom_L: no hdd activity
07:04 PM rue_mohr: so it just died then
07:05 PM Tom_L: i guess, i'm not gettin anything from it
07:05 PM rue_mohr: any beep codes?
07:05 PM Tom_L: nothing
07:05 PM rue_mohr: do you have a non-sound card speaker onit?
07:06 PM Tom_L: the cmos battery was dead so i changed that
07:06 PM Tom_L: i get nothing at all
07:06 PM rue_mohr: did you try a cmos reset then?
07:06 PM Tom_L: removing the battery won't do that?
07:06 PM rue_mohr: no
07:06 PM rue_mohr: there is a jumper
07:06 PM Tom_L: i'll have to look that up yeah
07:06 PM rue_mohr: they all work differnt
07:07 PM Tom_L: very odd
07:07 PM rue_mohr: based on the history I dont have a lot of optomism
07:07 PM Tom_L: likely so
07:07 PM Tom_L: went from working to nothing just like that
07:07 PM Tom_L: nothing physically changed
07:08 PM rue_mohr: maybe a silicon fail
07:08 PM Tom_L: could be
07:08 PM rue_mohr: is VSB ok?
07:08 PM rue_mohr: +5V
07:09 PM Tom_L: what is VSB?
07:09 PM Tom_L: i have 5v yes
07:09 PM rue_mohr: stand by votlage
07:09 PM Tom_L: 12 5 3 all
07:09 PM rue_mohr: vsb is always-on 5V
07:09 PM rue_mohr: k
07:09 PM rue_mohr: so the atx power circuit is working
07:09 PM Tom_L: tried 2 psu
07:09 PM rue_mohr: can you change the cpu on that one?
07:10 PM Tom_L: i dunno
07:10 PM Tom_L: it's all covered up
07:11 PM rue_mohr: hmm
07:11 PM rue_mohr: reset bios first
07:12 PM rue_mohr: I'v seen that cause machines to not start up
07:12 PM rue_mohr: if the atx power circuit is working, thats a whole bunch of stuff
07:12 PM Tom_L: trying to find it
07:16 PM Tom_L: does the cmos battery need to be in for that to work?
07:16 PM rue_mohr: usually needs to be out
07:16 PM rue_mohr: sometimes you have to turn the powr on for it to take effect
07:17 PM Tom_L: how does that happen with no power?
07:17 PM rue_mohr: I have seen all sorts of annoying conbinations
07:17 PM rue_mohr: sometimes its cleared if its invalid
07:17 PM rue_mohr: soemtimest eh jumpter tells things to clear ti on start
07:17 PM Tom_L: yeah battery out
07:17 PM Tom_L: done
07:18 PM rue_mohr: k...
07:18 PM rue_mohr: ?
07:18 PM Tom_L: try again
07:18 PM Tom_L: i unplugged everything.. one sec
07:21 PM Tom_L: nothing
07:21 PM rue_mohr: I think you had a silicon fail
07:22 PM Tom_L: still got an old old clunker i can put back in i guess
07:23 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/itx/EPIA-MII-45.jpg
07:23 PM Tom_L: hate to though
07:23 PM rue_mohr: I keep lots of extra hardware
07:23 PM Tom_L: i can't
07:23 PM rue_mohr: yea
07:24 PM Tom_L: not what i had in mind for tonight
07:25 PM Tom_L: cpu you think?
07:25 PM Tom_L: nothing _looks_ bad
07:25 PM rue_mohr: if the caps are ok, must be
07:25 PM Tom_L: i got a rpi
07:25 PM Tom_L: ;)
07:25 PM rue_mohr: that'll do irc
07:26 PM Tom_L: doubt that would do well on all the time for irc
07:26 PM Tom_L: odd i get no beeps etc
07:26 PM Tom_L: must really be dead
07:27 PM rue_mohr: bgas
07:27 PM rue_mohr: you got 3 on there I can see
07:27 PM rue_mohr: bgas dont last long
07:27 PM rue_mohr: a bit longer than caps
07:28 PM Tom_L: not this one :)
07:28 PM rue_mohr: on average
07:28 PM Tom_L: the board is still available
07:28 PM rue_mohr: hmm
07:29 PM Tom_L: how do you tell if the memory is ddr3 or ddr4?
07:29 PM rue_mohr: the key notch should give it away
07:30 PM Tom_L: i just looked at the box
07:30 PM rue_mohr: https://www.atpinc.com/upload/images/2020/04-22/38e598da6aea4fbcbb46fd9d231d49eb.jpg
07:30 PM Tom_L: these are short
07:31 PM rue_mohr: oh laptop memory
07:31 PM Tom_L: ~3"
07:31 PM rue_mohr: https://www.stechies.com/userfiles/images/DDR3vsDDR4jpg1559301648.jpg
07:31 PM rue_mohr: pin density?
07:31 PM Tom_L: this is ddr3
07:32 PM rue_mohr: grrr, darn analog encoders
07:38 PM Tom_L: ok that won't work
07:38 PM Tom_L: it's pata not sata
07:52 PM Tom_L: maybe i can use the rpi until i get a board
08:18 PM Tom_L: good i have an rpi :)
08:23 PM Tom_L: irc is dead anyway
08:27 PM rue_mohr: ...
08:27 PM rue_mohr: my scope can save channels to disk in CSV
08:27 PM Tom_L: nice
08:29 PM Tom_L: any newer MB and i wouldn't be able to use dos with it
08:30 PM Tom_L: i still use it for a few things on it
08:44 PM rue_shop1: hmm
08:59 PM Tom_L: why are you wanting to know stepper latency?
08:59 PM rue_mohr: because I want to make a step/direction DC servo
08:59 PM rue_mohr: and I need to know what performance I need
08:59 PM Tom_L: are you measuring the input against the output?
08:59 PM rue_mohr: yes
09:00 PM rue_mohr: the input is instant
09:00 PM rue_mohr: step command goes thru the tiny13 "instantly"
09:00 PM rue_mohr: the drivers also have no delay
09:00 PM rue_mohr: esp compared to the .3ms it takes for the shaft to start moving
09:01 PM Tom_L: drivers have _some_ delay due to ppg delay
09:02 PM rue_mohr: not compared to the 300us the mechanics take to start moving
09:02 PM Tom_L: yeah
09:05 PM Tom_L: i can say i've never had a mb die on me
09:05 PM Tom_L: well i can't say that...
09:06 PM Tom_L: now
09:11 PM rue_shop1: OMG it can print the CSV to the serial port without crashing too
09:11 PM rue_shop1: still slow, I need to make the parallel thing
09:15 PM Tom_L: the scope?
09:47 PM aandrew: Tom_L: irc is not dead
09:47 PM aandrew: bite your tongue
09:48 PM aandrew: rue_shop1: dump csv to serial would be handy
09:48 PM aandrew: you can suck that shit up with a simple program and spit out a png
09:51 PM Tom_L: O U C H Dammit!!!
10:31 PM rue_shop1: well
10:31 PM rue_shop1: the problem is that you can directly send the capture to serial
10:31 PM rue_shop1: you have to save it to file (which you can only do 1 channel)
10:31 PM rue_shop1: and then send the file to serial port
10:31 PM rue_shop1: at 19200 baud max
10:32 PM rue_shop1: I need to make a parallel -> 115200 baud thing
10:32 PM rue_shop1: stm32
10:33 PM Tom_Rpi: fpga
10:40 PM Tom_Rpi is now known as Tom_L
10:40 PM rue_shop1: hahah
10:40 PM rue_shop1: too expensive