#garfield Logs

Feb 22 2021

04:46 AM polprog: Tom_L: yea, this is something similar
04:53 AM polprog: although i realized i didnt connect the attiny to the secondary uart :( i can still fix it
04:53 AM polprog: revision 1A here i come
08:54 AM polprog: there isnt all that much to run from that 12V, it's just the analog supply for the opamps and stuff. I have to sit to it and measure it all
08:55 AM polprog: worst case scenario it will just run off a DC jack, and buck the 12V down to 5
09:08 AM rue_mohr: usbc :)
09:10 AM rue_mohr: ok, yea it wont be too pickey on the 12V then, 9V -> 12.5 should be fine
09:10 AM rue_mohr: so I suggest a forward converter
09:10 AM rue_mohr: did you see the unregulated ones I made?
09:17 AM rue_mohr: armstrong oscillator paired up with a forward converter
09:28 AM polprog: hmm
09:30 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180746.jpg
09:30 AM rue_mohr: so yea
09:30 AM rue_mohr: 6 components, I was proud
09:31 AM rue_mohr: because its based on a forward converter, its just controlled by the turns ratio
09:31 AM polprog: eventually id probably use an IC but it's gonna be fun to try that
09:31 AM rue_mohr: that one could even be optimized due to the fact the feedback is the same polarity
09:31 AM rue_mohr: if your input is regulated, your find
09:31 AM rue_mohr: fine
09:35 AM rue_mohr: you want to make sure the primary needs enough turns that you can get the right ratio
09:35 AM rue_mohr: or close
09:39 AM rue_mohr: dont forget a big bypass cap, like 47-100uF
10:12 AM polprog: yeah..
10:13 AM polprog: what converter did i do last time
12:44 PM Tom_L: https://www.youtube.com/watch?v=ZIOn6w7gwWU&feature=youtu.be
05:39 PM aandrew: black tie and pocket square acquired. shoes have polish applied, 10m or so time to make 'em shine
05:39 PM aandrew: that's probably one of the vanishingly few things I miss about the "before covid" work days
05:39 PM aandrew: I used to fairly regularly shine my shoes
06:51 PM rue_mohr: tom I'v done that
06:52 PM rue_mohr: the precut method in nice tho
06:52 PM rue_mohr: I had a hard time starting mine
06:54 PM Tom_L: https://www.ebay.com/itm/1-1-2-C360-BRASS-HEX-BAR-12-long-New-Lathe-Bar-Stock-1-50-Hex-1-2-Hard/352364633527?hash=item520a919db7:g:PPEAAOSwTFhbCJvl
06:55 PM Tom_L: how many test caps do you want?
07:05 PM rue_mohr: $6/inch OUCH
07:05 PM rue_mohr: and thats too small
07:06 PM Tom_L: you think?
07:06 PM rue_mohr: 1.5"
07:06 PM Tom_L: oh yeah you're right
07:06 PM Tom_L: so 2" i should be looking for
07:06 PM Tom_L: that would give .250 wall
07:06 PM rue_mohr: 1/2" sidewalls is probably overkill
07:06 PM Tom_L: 1/4
07:06 PM rue_mohr: hahah math fail
07:06 PM rue_mohr: yes
07:07 PM rue_mohr: hah, atleast Ik now that 1.5-1.5 = 0
07:07 PM rue_mohr: hahaha
07:07 PM rue_mohr: oooh stressfull work day :)
07:09 PM Tom_L: https://www.ebay.com/itm/CHEAP-BRASS-C360-Solid-Hex-Bar-12-Long-2-12-6/264195334718?hash=item3d8344e23e:g:VZcAAOSwyutcZE2L
07:09 PM Tom_L: less than the 1.5"
07:09 PM Tom_L: doesn't sound right
07:11 PM Tom_L: the weight is right or close
07:13 PM rue_mohr: I forgot to do the tank hydro test on the weekend
07:15 PM rue_mohr: I have to rest my eyes for a min tho
07:15 PM * Tom_L sets a timer
07:21 PM rue_mohr: https://www.youtube.com/watch?v=f-YWsgAHR6A
07:21 PM rue_mohr: needs sound
07:22 PM Tom_L: none here
07:23 PM Tom_L: someone posted that in linuxcnc
07:23 PM Tom_L: my threads look better :)
07:25 PM Tom_L: several ways you can go wrong using the tap
07:25 PM Tom_L: alignment
07:25 PM Tom_L: but it _is_ doable
07:26 PM rue_mohr: yea, I was pondering doing something like that
07:27 PM Tom_L: has to be on center and parallel to the work with the rake set right
07:27 PM Tom_L: all things that can mess it up
07:28 PM Tom_L: several passes have to be repeatable
07:28 PM Tom_L: my bud's lathe has an indicator on the screw to engage it so you don't have to reverse out
07:28 PM Tom_L: reversing out will cause backlash too
07:29 PM rue_mohr: he backs off and reverses from what I saw
07:32 PM Tom_L: he puts out some good videos
08:18 PM rue_mohr: !!!
08:18 PM Tom_L: ???
08:19 PM Tom_L: ole tony
08:20 PM Tom_L: https://www.youtube.com/c/ThisOldTony/videos
08:24 PM rue_mohr: i'm awake
08:24 PM Tom_L: uh huh
08:25 PM Tom_L: i'm santa claus
08:33 PM rue_mohr: ugh
08:33 PM rue_mohr: ok, test pump
08:33 PM rue_mohr: tak
08:33 PM rue_mohr: tank
08:39 PM rue_shop1: ok
08:40 PM rue_shop1: need 2 plugs
08:42 PM rue_shop1: it has a plug in the top I can use for an air purge
08:45 PM rue_shop1: 150%, 200% or 300% swp?
08:45 PM rue_shop1: sop?
08:46 PM Tom_L: ?
08:47 PM rue_shop1: ??? there was like 10psi in there
08:48 PM rue_shop1: hydrostatic test for an air tank
09:12 PM rue_shop1: Hydrostatic Pressure = 1.3 x MAWP or Design Pressure x ( stress value at Test Temperature / stress value at design temprature ).
09:13 PM rue_shop1: https://letsfab.in/hydro-static-pressure-calculation/
09:14 PM Tom_L: so how far do you push it?
09:16 PM rue_shop1: 150psi
09:16 PM rue_shop1: * 1.3
09:17 PM rue_shop1: so 195
09:17 PM rue_shop1: oh its more complicated
09:17 PM rue_shop1: its 150 @
09:18 PM rue_shop1: 450*F
09:18 PM rue_shop1: so, whats the temp now
09:19 PM rue_shop1: its 7*C now
09:19 PM rue_shop1: 44.6*F
09:20 PM rue_shop1: Hydrostatic Pressure = 1.3 x MAWP or Design Pressure x ( stress value at Test Temperature / stress value at design temprature ).
09:20 PM rue_shop1: (or)
09:20 PM rue_shop1: ok, I'll go with 1.3
09:26 PM rue_shop1: windstorm
09:26 PM Tom_L: ?
09:34 PM rue_shop1: I might be 1 1/8" plug away from being able to do this...
09:37 PM rue_shop1: ok, all the hardware is off and the holes are plugged
09:40 PM rue_shop1: thats not half inch, thats 3/4
09:49 PM rue_shop1: rain
09:49 PM rue_shop1: bleckh
10:06 PM rue_shop1: ok, its at 200
10:07 PM rue_shop1: wait for a big
10:07 PM rue_shop1: bit
10:08 PM Tom_L: yeah, how long does it hold the pressure for a pass?
10:08 PM rue_shop1: https://letsfab.in/hydro-static-pressure-calculation/
10:09 PM rue_shop1: I'm guessing an hour...
10:09 PM Tom_L: i'm not gonna wait up :)
10:09 PM rue_shop1: np
10:09 PM rue_shop1: there is no bing bang sound happening
10:12 PM Tom_L: that's a good thing
10:12 PM rue_shop1: pressure was dropping a big, might be changing shape a bit
10:13 PM rue_shop1: dropping a bit
10:13 PM rue_shop1: I cant type anymore
10:16 PM rue_shop1: oh the valve I used in the bottom drain wasn't closed tight
10:20 PM rue_shop1: man, with that pump, I could hit 200 psi with my pinkey finger
10:20 PM Tom_L: :)
10:23 PM rue_mohr: images in a sec
10:24 PM rue_mohr: ok, image
10:24 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1180751.jpg
10:28 PM Tom_L: where does the 2nd hose go?
10:28 PM rue_mohr: tap
10:28 PM rue_mohr: rapid fill :)
10:29 PM Tom_L: k
10:29 PM Tom_L: practicing for the extinguishers?
10:31 PM rue_mohr: partly
10:31 PM rue_mohr: I'm doing a fire hose system on friday
10:31 PM rue_mohr: I need to know if everything works :)
10:32 PM rue_mohr: hmm, well the waiting part is boring
10:32 PM rue_mohr: possibly good its not exciting
11:06 PM rue_mohr: .
11:07 PM rue_mohr: 19:55:01 its at 200
11:14 PM rue_shop1: ok thats a pass
11:29 PM rue_mohr: I really wasn't sure if it would
11:29 PM rue_mohr: tommorow I need to drive the water out of it.