#garfield Logs
May 09 2020
#garfield Calendar
12:55 AM zhanx__ is now known as zhanx
01:01 AM zhanx: 3d printer bonus
01:01 AM zhanx: printer adapters for the buddies cpap machine
01:14 AM rue_mohr: cpap... Iv' heard of that before...
01:14 AM zhanx: its a sleep thing i guesss
01:16 AM rue_mohr: k
01:16 AM rue_mohr: I'm etching a pcb!
01:16 AM rue_mohr: or gonna
01:16 AM rue_mohr: a motor driver
01:17 AM rue_mohr: the only improvment I'd like to make is that it be run/coast instead of run/brake
01:17 AM rue_mohr: but for what I'm doing I dont think it matters
01:18 AM rue_mohr: I had a 1 evening project to "just do whatever and drive the motors"
01:18 AM rue_mohr: been working on it for about 3 weeks now
01:18 AM rue_mohr: cause motor divers that drop 3V are not my thing
01:18 AM rue_mohr: that said, this driver pushes over a watt idle
01:19 AM zhanx: last interview is monday at 11 am
01:19 AM rue_mohr: last one ever?
01:19 AM zhanx: well for this job
01:19 AM rue_mohr: more than 1 interview for the same job?
01:19 AM zhanx: down to me and one other person now
01:20 AM zhanx: 5 so far
01:20 AM rue_mohr: I wonder if their employees are disposable in the end
01:20 AM zhanx: not really they are super picky and want long term
01:20 AM rue_mohr: cool
01:21 AM rue_mohr: after this you will have good internet, right?
01:21 AM zhanx: have them now
01:21 AM rue_mohr: good show
01:21 AM zhanx: the wifi card in this pc just hates linux is all
01:21 AM rue_mohr: gee I'm tired
01:21 AM rue_mohr: use wired...
01:22 AM zhanx: don't feel like running the wire around stuff
01:23 AM rue_mohr: drat I'm showing signs of being really tired, I wonder if I should do this pcb tommroow
01:23 AM rue_mohr: I think I should
06:12 AM polprog: 15,99[06:34] 3,99rue_shop1:99,99 polprog, doc it for me eh?
06:12 AM polprog: the uln one? sure
06:13 AM polprog: i have to build a pendulum now for a lab
06:17 AM polprog: ill probably want to measure it up a bit as well
06:17 AM polprog: at least output voltage/power/efficienty in function of input voltage
06:19 AM polprog: we have lab classes done remotely.. this one is measuring g with a pendulum
06:20 AM polprog: using that super thin wire i hung two toroidal cores from a DIN rail
06:20 AM polprog: :D
06:20 AM polprog: i think i could ignore all the inductive effects due to the mass being a sortof inductor now :P
07:03 AM Tom_L: yes cpap is for sleep disorders
07:04 AM Tom_L: rue_mohr, thanks i got the script running 10k iterations
07:04 AM Tom_L: (testing a memory leak)
07:19 AM polprog: https://www.southpolestation.com/trivia/00s/southpolefoucault.html
07:22 AM Tom_L: you on the right?
07:22 AM polprog: haha, yes, in 20 years' time
11:59 AM rue_bed: morning
12:00 PM rue_bed: hmm, gravity with a pendulum
12:00 PM Tom_L: hey
12:00 PM rue_bed: hay
12:04 PM rue_bed: so, I have a board design to etch today
12:04 PM rue_bed: and I'd like to teach polprog about inductor saturation testing
12:05 PM rue_bed: need to put gas in the truck
12:05 PM rue_bed: price jumped from 0.994 to 0.999
12:06 PM rue_bed: so it
12:06 PM rue_bed: 'll snap back to 1.500 pretty fast
12:21 PM polprog: https://polprog.net/rozne1/ircjunk/dcdc/uln2003boost.jpg
12:22 PM polprog: i must have been sitting the wrong way, the drawing got crooked..
12:32 PM polprog: rue_bed: ^
12:33 PM rue_mohr: heh
12:33 PM rue_mohr: you can put the capacitor between the output and +
12:33 PM polprog: hmm.. yeah
12:33 PM rue_mohr: then you dont need a capacitor rated for the full voltage
12:33 PM rue_mohr: meaning you can use a smaller or higher capacity capacitor
12:34 PM rue_mohr: :)
12:34 PM polprog: i think the standard voltages ar 16, 25, 50... so not much use
12:34 PM polprog: unledd you wanna swap a 16V for a 25
12:34 PM polprog: er
12:34 PM polprog: the other way around
12:34 PM polprog: the PCB design uses a 25V rated cap but the output unloaded (loaded with just the led) is 32-ish x_x
12:35 PM polprog: 330uF
12:35 PM rue_mohr: I'm kinda surprised nobody mentioned it on twitter
12:35 PM polprog: did i post the done design on twitter? i think i only posted the rasterboard build
12:35 PM rue_mohr: all my 24V converters use a 16V cap to +
12:35 PM aandrew: most people aren't that observant :-)
12:35 PM rue_mohr: :(
12:35 PM rue_mohr: oh well
12:36 PM polprog: most people dont make their inductors from coils found on the ground outside
12:36 PM rue_mohr: polprog, I saw the photo
12:36 PM rue_mohr: :)
12:36 PM * polprog only uses locally sourced, naturally occuring electronic components from the nearby forests
12:37 PM Tom_L: non gmo?
12:37 PM polprog: rue_mohr: also did you watch my video about the industrial modem? i ran a direct connection there (re: Miga's twitter modems)
12:37 PM polprog: Tom_L: yes, fair trade, vegan, lactose^Wlead free
12:37 PM rue_mohr: free range :)
12:37 PM polprog: :D
12:38 PM rue_mohr: I think twitter doesn't show all of the posts eh?
12:38 PM polprog: it was quite a long time ago
12:38 PM rue_mohr: I'v gone thru people and found things it didn't show me
12:39 PM rue_mohr: still
12:40 PM polprog: i think i posted it before you started following me
12:40 PM polprog: actually, maybe even before i found this solitude :P
12:40 PM rue_mohr: I cant even get back to the start of my own
12:41 PM polprog: me neither
12:41 PM polprog: ill characterize the efficiency vs input voltage later
12:42 PM polprog: gotta put the pendulum data into excel
12:42 PM polprog: id like to have this done on monday..
12:43 PM polprog: are you using Letter or A4 paper in your file?
12:44 PM rue_mohr: 8.5x11
12:44 PM polprog: ok, youll have to rescale that scan then :P
12:44 PM rue_mohr: :)
01:39 PM rue_shop1: Tom_L, so, the stubby pens dont work in the holders I have
01:39 PM rue_shop1: need to make up a new one
01:43 PM Tom_L: but the pens are good?
01:43 PM rue_shop1: I didn't test the ink, I'm sure its fine
01:43 PM rue_shop1: oh, hmm these pens might be too fat
01:45 PM rue_mohr: I wonder if 0.2mm matters
01:47 PM rue_shop1: oh my, this is complicated
01:48 PM rue_shop1: the bit where the cap clips on is were it needs to be 11.5mm, but with the cap off, its 9.5mm
01:49 PM rue_shop1: and where a flange needs to go, its already jumped to 11.7mm
02:36 PM Tom_L: rue_shop1, you have a pi?
02:36 PM rue_mohr: yuop, remember I used it to take images that posted directly to the site?
02:36 PM Tom_L: no
02:37 PM Tom_L: pi4?
02:37 PM rue_mohr: hahah
02:37 PM rue_mohr: its like a pi 1
02:37 PM Tom_L: pi4 works best on lcnc and that's why i would be getting it to test
02:37 PM rue_mohr: I'm unlikley to just go out and buy a pi
02:37 PM rue_mohr: k
02:37 PM Tom_L: me either right now
02:42 PM rue_mohr: my understanding is that their not expensive, but I cant find the place that sells them for the good prices
02:42 PM rue_mohr: to canada
03:39 PM polprog: https://pasteall.org/pic/874f8d8221ae480fb7dbe55ac51e95a7
03:39 PM polprog: airflow controller found in an abandoned building
03:40 PM polprog: the scrappies cut it off from the mains cables and left it there.. has some gerabox mechanism on the mottom
03:40 PM polprog: but im curious why are there only 3 mosfets driving the motor
03:40 PM polprog: 3 wunding unipolar?
03:40 PM polprog: winding*
03:45 PM Tom_L: not 3phase ac is it?
03:45 PM Tom_L: like a vfd
03:46 PM polprog: no, it seems that the drains go to a cap and a..
03:46 PM polprog: good question
03:46 PM polprog: two diodes?
03:46 PM polprog: where are the other two
03:46 PM Tom_L: i didn't click. just guessed
03:47 PM polprog: i should beep it out
03:52 PM polprog: might not be mosfets after all
03:52 PM polprog: but one side of soic is connected together 4 pins
04:01 PM rue_shop1: 3 phase motor
04:01 PM rue_shop1: dual fet packs
04:03 PM polprog: damn, youre right
04:03 PM polprog: pin 1's are common on all 3, and so are pin 3's
04:03 PM polprog: the motor will come in handy
04:04 PM polprog: maybe it has windings on the PCB
04:04 PM polprog: since it rotates around it
04:55 PM rue_shop1: :)
04:58 PM polprog: added a coax cable to the VHF ant
04:58 PM polprog: i have a sec before i hit the bed
04:58 PM polprog: you wanted to teach me your ways
05:04 PM rue_shop1: for which?
05:04 PM rue_shop1: I never remember where things were at
05:11 PM polprog: 19:04 < rue_bed> and I'd like to teach polprog about inductor saturation testing
05:13 PM rue_shop1: ooh
05:13 PM rue_shop1: that'll take some setup
05:13 PM rue_shop1: we need to make a really fine control pwm gen, and a FET coil driver!
05:21 PM polprog: hmm
05:21 PM polprog: gimme a moment
05:27 PM rue_shop1: heh
05:27 PM rue_shop1: I'd used my op-amp pwm circuit
05:27 PM rue_shop1: and an IRFZ44 or the like
05:28 PM polprog: which one is it?
05:28 PM rue_shop1: you also need a current sense resistor, like 0.1 ohms or so
05:28 PM rue_shop1: the op-amp pwm?
05:28 PM polprog: ill see if i have an IRF something
05:28 PM polprog: yeah
05:28 PM rue_shop1: I think its like one you made
05:28 PM polprog: like the relax?
05:28 PM rue_shop1: 1 op-amps, one generating a ramp and the other as a comparator
05:28 PM polprog: ill probably put a diode in one way to make it a sawtooth
05:28 PM polprog: ok
05:28 PM rue_shop1: dont worry about sawtooth
05:28 PM rue_shop1: the phase doesn't matter
05:29 PM polprog: i know
05:29 PM rue_shop1: :) kinda deep into my circuit assembly just now
05:30 PM polprog: yeah i just finished testing the vhf ant with sdr
05:30 PM polprog: pretty good directionality
05:30 PM polprog: i mean
05:30 PM polprog: it is directional
05:30 PM polprog: how directional is it i have no idea
05:32 PM polprog: got a .56ohm
05:34 PM polprog: .27
05:37 PM polprog: lol. parents are asleep
05:37 PM polprog: the scope floppy drive is sooo loud
05:37 PM polprog: it does a seek on boot
05:39 PM polprog: 3khz enough>
05:39 PM polprog: ?
05:47 PM aandrew: yanno... cisco switch ports work a lot better when you don't forget about a monitor session that you set up like 3mo ago on the fucking port
05:52 PM polprog: done, pwm at 3.53khz
06:09 PM polprog: fixed the shit Hama tripod
06:10 PM rue_mohr: polprog, you want the pwm to fast drive a fet
06:11 PM rue_mohr: polprog,
06:11 PM rue_mohr: heh, I forgot
06:11 PM rue_mohr: http://ruemohr.org/~ircjunk/circuits/measind/
06:12 PM rue_mohr: so my freq was
06:12 PM rue_mohr: 450Hz *ish
06:12 PM polprog: http://ruemohr.org/~ircjunk/circuits/measind/dscn4434.jpg
06:13 PM polprog: i dig that pot
06:13 PM polprog: ok, let me switch the cap to 470n
06:13 PM rue_mohr: :)
06:13 PM rue_mohr: http://ruemohr.org/~ircjunk/circuits/measind/dscn4438.jpg
06:13 PM polprog: 216 hz
06:13 PM rue_mohr: the idea, is to slowly increase the duty
06:13 PM rue_mohr: monitor the current, you will see a "knee"
06:14 PM rue_mohr: where it goes from a linear increase to an exponential one
06:14 PM rue_mohr: thats where the inductor saturated
06:14 PM polprog: ok, let me try
06:14 PM rue_mohr: but!!!
06:14 PM rue_mohr: you need to also dump the energy your putting into the inductor
06:14 PM rue_mohr: http://ruemohr.org/~ircjunk/circuits/measind/dscn4441.jpg
06:15 PM rue_mohr: see the diode and load resistor?
06:15 PM rue_mohr: the big ceramic one on the top right
06:15 PM polprog: yeah
06:15 PM rue_mohr: the two 0.2 ohm resistors are my current sense
06:16 PM rue_mohr: http://ruemohr.org/~ircjunk/circuits/measind/measureind.gif
06:16 PM rue_mohr: I did draw it in
06:16 PM rue_mohr: :)
06:16 PM rue_mohr: shall I leave you to it for a bit?
06:16 PM polprog: if you want to
06:17 PM rue_mohr: the slope before the saturation will tell you the inductance
06:17 PM rue_mohr: the knee shows you the core saturation
06:17 PM rue_mohr: then you know just how hard you can push it
06:22 PM polprog: weird
06:22 PM polprog: overvoltage protection kicks in on the PSU
06:23 PM polprog: im getting 116V peaks on the scope x_X
06:29 PM polprog: added a 5.1V zener to vcc, running from 6V it seems to help
06:50 PM polprog: sense R is 1ohm
06:53 PM polprog: https://polprog.net/rozne1/ircjunk/various/PRINT_02.jpeg
06:53 PM polprog: https://polprog.net/rozne1/ircjunk/various/PRINT_03.jpeg
07:04 PM polprog: ah, no, sense is .22
07:44 PM polprog: short of 5 amps peak
08:00 PM aandrew: oof, mouth full of peanut butter
08:06 PM polprog: nighters
08:40 PM rue_mohr: oh !
08:40 PM rue_mohr: you need a stronger suppression load
08:41 PM rue_mohr: you need to zoom in more the fet is much smaller than mine, its saturating before you can see it happening
09:59 PM rue_mohr: so tom I had an amusing thought
09:59 PM rue_mohr: the aluminum mold
09:59 PM rue_mohr: it *might* still work if it was aluminum
09:59 PM Tom_L: oh?
10:00 PM rue_mohr: I dont think enough heat would transfer while casting to screw it up
10:00 PM rue_mohr: it was a thought
10:00 PM Tom_L: didn't you have to preheat the mold some?
10:00 PM Tom_L: the aluminum would probably warp more
10:00 PM rue_mohr: it was debatable if that'd helped or not
10:01 PM rue_mohr: maybe
10:01 PM rue_mohr: I would say the design would be well in the "danger zone"
10:03 PM Tom_L: i'm tempting myself to get a rpi
10:03 PM Tom_L: talk me out of it
10:03 PM rue_mohr: how much are they worth$ ?
10:04 PM zhanx: 35 dollars
10:04 PM Tom_L: kit with the heatsink case i want is about 115
10:04 PM rue_mohr: so, we have an $80 discrepency
10:05 PM rue_mohr: Tom_L, how much does a month of tv cost up there?
10:05 PM Tom_L: if you just get the board it's a bit more than what z said
10:05 PM Tom_L: https://www.amazon.com/gp/product/B07XTQL6YZ/
10:05 PM Tom_L: https://www.amazon.com/Metal-Raspberry-Heatsink-Thermal-Adhesive/dp/B07VMD25SK
10:05 PM Tom_L: no fan needed
10:05 PM rue_mohr: ok
10:06 PM rue_mohr: and how much is a month of tv?
10:06 PM Tom_L: more
10:06 PM zhanx: 10 bucks to me
10:06 PM rue_mohr: hmm, and how much is in your play budget, you know, the money you dont plan to spend, but likley will anyhow?
10:07 PM Tom_L: mine is in spurts. go thru a dry spell then get something
10:07 PM rue_mohr: hmm
10:07 PM zhanx: right now zero
10:07 PM rue_mohr: zhanx, you holding in ok?
10:07 PM zhanx: sure
10:08 PM zhanx: define ok
10:08 PM rue_mohr: how long till your done with the bridge solution
10:08 PM zhanx: never
10:08 PM rue_mohr: something go wrong?
10:08 PM zhanx: life
10:08 PM rue_mohr: hmm
10:08 PM zhanx: don't worry about
10:09 PM zhanx: last interview for new job is monday
10:09 PM zhanx: then things will get easier
10:09 PM rue_mohr: you live one hell of a rollercoaster you know.
10:09 PM zhanx: yes i do
10:09 PM Tom_L: i thought you already had the interview
10:09 PM zhanx: one of 5
10:09 PM rue_mohr: 5 of 6
10:09 PM Tom_L: jees
10:09 PM rue_mohr: ?
10:09 PM zhanx: last one is monday for sure
10:09 PM zhanx: i did the drug test
10:10 PM rue_mohr: you didn't trip out too bad when they gave you drugs?
10:10 PM zhanx: they seem to vet well
10:10 PM zhanx: i palmed them
10:11 PM rue_mohr: oh I'm losing focus
10:11 PM rue_mohr: I need to design another pcb
10:11 PM zhanx: same here
10:11 PM zhanx: i think these tiny 9g servo's suck
10:11 PM zhanx: they will not repeat things
10:12 PM zhanx: you can't calibrate things if they fail to move half the time
10:14 PM rue_mohr: :/
10:14 PM rue_mohr: I was wondering that while playing with mine
10:14 PM rue_mohr: iirc the deadzone was kinda huge
10:14 PM rue_mohr: less than one that burned itself out cause it had negitive deadzone
10:15 PM rue_mohr: ruemohr.org/~ircjunk/projects/tiltnpanmirror/
10:15 PM Tom_L: rue_mohr, does the pi ship with an os?
10:15 PM zhanx: Tom_L, no
10:15 PM rue_mohr: http://ruemohr.org/~ircjunk/projects/tiltnpanmirror/p1160048.jpg
10:15 PM Tom_L: bootloader?
10:15 PM Tom_L: pi4
10:15 PM zhanx: kind of
10:15 PM rue_mohr: that was todays work
10:15 PM Tom_L: i was told they load an image from the sd
10:15 PM Tom_L: ?
10:15 PM rue_mohr: Tom_L, you download/configure an image on sd and shove it in
10:16 PM Tom_L: ok so you start with a cd image or such and configure the sd for it
10:16 PM Tom_L: ?
10:16 PM rue_mohr: you download an image
10:17 PM rue_mohr: dont recall where from
10:17 PM Tom_L: this would be a special one
10:17 PM rue_mohr: I barely remember doing it
10:18 PM rue_mohr: so, I built one of those drivers on protoboard and it took me a week+
10:18 PM rue_mohr: that one took me a day (lots of visitor stuff during to day too)
10:20 PM Tom_L: https://zaphod.unpythonic.net/pi/
10:20 PM Tom_L: lcnc image for it
10:21 PM Tom_L: experimental
10:22 PM zhanx: lcnc for pi?
10:22 PM Tom_L: yes
10:22 PM zhanx: getting it to help you
10:23 PM Tom_L: i don't even have one yet
10:23 PM zhanx: the newest full version
10:23 PM Tom_L: and that one is very experimental
10:23 PM Tom_L: not really for public consumption
10:23 PM zhanx: so.....
10:24 PM Tom_L: 2020-05-01 zip
10:24 PM Tom_L: last one
10:24 PM Tom_L: 1.1g
10:24 PM Tom_L: ~3g img file zipped
10:25 PM zhanx: yep
10:25 PM zhanx: Tom_L, i have a pi s
10:25 PM zhanx: so
10:25 PM zhanx: i can walk along with you on it
10:25 PM Tom_L: only works on the 4
10:26 PM Tom_L: but the performance on it is as good or better than the D525 i've got on my mill now
10:26 PM Tom_L: you have to run a slower servo thread
10:27 PM Tom_L: but with ethernet or spi that shouldn't be a problem
10:27 PM Tom_L: i have both
10:29 PM zhanx: we can do that when you get it
10:29 PM zhanx: but i have the hardware to help test with
10:35 PM Tom_L: ok, i'm somewhat undecided on it right now though
10:35 PM Tom_L: playing catchup after being off 2 months
10:40 PM Tom_L: they make a mesa board for it as well but i'm not using it
10:41 PM zhanx: well i have the pi for this new bot so i can test software but not gettig a mesa board
10:41 PM zhanx: but if needed i can remote in the pi on screen with you
10:42 PM zhanx: tons of options later
10:42 PM Tom_L: i have to get one first
10:42 PM Tom_L: more than i'd pay but: http://store.mesanet.com/index.php?route=product/search&search=7c80
10:43 PM Tom_L: full motion control for it
10:44 PM Tom_L: the 7c81 is alot cheaper