#garfield Logs

Sep 01 2021

12:38 AM rue_mohr: I'm gonna try a reverse engineering thing on a board
01:20 AM rue_shop3: finding a bunch of 80C154 chips, turns out, its a take-off of 8051
02:20 AM polprog: hmm
02:20 AM polprog: i woke up and have a sore throat
02:21 AM polprog: if the NMI pin on that z80 board wasnt pulled down it would make a great candidate for the automatic detection program
02:22 AM polprog: i wrote a C program yesterday that tests every memory location but i think i have to rewrite it in assembly
02:22 AM polprog: breakfast time
03:11 AM rue_shop3: unlock the NMI
04:07 AM polprog: thats one way
04:07 AM polprog: id have to desolder the whole chip tho
04:10 AM Tom_L: morning
04:13 AM polprog: morning
04:58 AM rue_mohr: its not a trace you can just cut?
05:15 AM rue_mohr: polprog, I need to finish building one of my programmers
05:15 AM rue_mohr: and I dont care if they require personality modules
07:23 AM polprog: i think its connected to the plane
07:23 AM polprog: good idea with these programmers
10:57 AM rue_mohr: my UPS is transfering for no reason again
10:58 AM rue_mohr: its done about 50 transfers now today
10:58 AM rue_mohr: I have 156 days uptime
10:58 AM rue_mohr: :/
11:00 AM rue_mohr: I probably have to shut down and tend to it
11:01 AM rue_mohr: I think its got something going wrong internal with a connecttion
11:41 AM rue_mohr: maybe its the detection circuit itself failing
11:41 AM rue_mohr: how do I restore all the terminals I have open!
12:28 PM polprog: hmm, try hibernating
12:59 PM rue_mohr: it doesn't
01:01 PM * Tom_L feels rue_mohr will be lonely the rest of the week
01:03 PM rue_mohr: this is why I have more than 1 computer now
01:04 PM Tom_L: i will check back in later next week
01:04 PM rue_mohr: ?
01:05 PM Tom_L: but just in case, you _DO_ have my number :)
01:05 PM rue_mohr: I lost it
01:05 PM rue_mohr: I dont know if I kept track of the cell one...
01:05 PM rue_mohr: but your vacationing for a bit?
01:06 PM Tom_L: i never answer the land line anyway
01:06 PM rue_mohr: ok
01:06 PM rue_mohr: ugh, I wonder if I have antoher ups
01:06 PM rue_mohr: I'm down to terminals
01:06 PM Tom_L: why?
01:07 PM rue_mohr: 25 of them
01:07 PM rue_mohr: I have to shut down and check the ups
01:07 PM rue_mohr: and I didn't install a bypass switch
01:07 PM Tom_L: expecting a catastrophy?
01:08 PM rue_mohr: I'm not sure if this thing will boot ok
01:08 PM rue_mohr: the ups keeps switching to battery, and nothing is going on
01:08 PM * Tom_L sees another project in the works for rue_mohr
01:09 PM rue_mohr: I think the votlage detection is failing, cap?
01:10 PM Tom_L: i dunno, i got a 750 in the closet that's been sitting there a few years
01:11 PM rue_mohr: I have a 200Ah battery
01:11 PM rue_mohr: lasts 8 hours or more
01:11 PM Tom_L: batteries are shot in it
01:11 PM rue_mohr: about 12 iirc
01:11 PM rue_mohr: that happens
01:11 PM Tom_L: had network monitoring
01:17 PM rue_mohr: this one has usb
01:18 PM rue_mohr: ok, I suppose I can play with RAM while its down
02:11 PM polprog: so basically i have a software uart implementation
02:11 PM polprog: where i have states TX_START, TX_BITS, and TX_STOP
02:11 PM polprog: but TX_START and TX_STOP are very similar, they transmit a 1
02:13 PM polprog: the only difference is int he flow graph, TX_START always goes to TX_BITS, TX_STOP goes to TX_START if the buffer is not empty or IDLE when its empty
02:13 PM polprog: is there any way to code that without repeating the part that sends a 1 (loop)
03:06 PM ruenahcmohr: ugh
03:07 PM ruenahcmohr: that UPS had more than bad caps
03:07 PM ruenahcmohr: its got a power issue to one of its supplies
03:07 PM ruenahcmohr: its not been powered down in maybe 3 or 4 years, so I didn't know
03:10 PM ruenahcmohr: LOADPCT : 22.0 Percent
03:10 PM ruenahcmohr: so I'm using another ups at the moment
03:10 PM ruenahcmohr: but
03:11 PM ruenahcmohr: I dont think its a good oen
03:14 PM ruenahcmohr: On-battery Waveshape
03:14 PM ruenahcmohr: Stepped Sine Wave
03:14 PM ruenahcmohr: grrr
03:14 PM ruenahcmohr: I think the other is true sine
03:20 PM ruenahcmohr: oh nope, it was stepped too
03:29 PM ruenahcmohr: yea stepped sine wave
04:02 PM ruenahcmohr: ok, seeing as I have no uptime, I'm gonna check some new ram
04:02 PM ruenahcmohr: and a new kernel
04:02 PM ruenahcmohr: caution, meet wind.
04:16 PM polprog: so my little ir doodad can transmit uart frames, and a receiver IC connected directly to a usb-uart adapter can receive data
04:17 PM polprog: running at 1200 baud now, but i can do 2400 easily
04:17 PM polprog: now i should implement the RX part on the microcontroller, i gotta write a software uart receiver
04:17 PM polprog: or i could route the rx input to the uart rx but im gonna need a software receiver anyway
04:18 PM polprog: i will do that tomorrow tho
04:29 PM rue_mohr: ok, well, I have 12G now anyhow
04:29 PM rue_mohr: it didn't like the really big server modules I have
04:29 PM rue_mohr: oh well
04:30 PM rue_mohr: oh and I'm on the new kernel, nfs might work
04:44 PM Tom_L: what kernel?
05:06 PM aandrew: hey polprog - do you have any (ancient) voodoofx boards?
05:14 PM polprog: no, i only have some ATi Rage and S3 boards
05:24 PM polprog: gn
05:57 PM rue_shop3: Tom_L, 5.4.1 iirc
06:05 PM Tom_L: is that a new one?
06:05 PM Tom_L: i think it may be
06:06 PM Tom_L: the preempt-rt in bullseye is based on 5.10
06:14 PM rue_mohr: I do not use super-new versions
06:14 PM rue_mohr: I wait for the bugs to be found
06:14 PM rue_mohr: still trip across lots of them tho
06:14 PM rue_mohr: so,
06:14 PM rue_mohr: funny as hell
06:15 PM rue_mohr: I just found two UPS control baords that had controllers that looked like 8051
06:15 PM rue_mohr: I put them in one of the boards that I put 8051 basic on and they ran!
06:16 PM rue_mohr: ok, if I want to do a casting i should do it now
06:16 PM rue_mohr: but I'm exhausted
06:29 PM Tom_L: first time they've released a preempt-rt with a distribution
06:29 PM rue_mohr: should I do the casting?
06:29 PM rue_mohr: I should do the casting
06:29 PM Tom_L: 8051 seems to pop up everywhere
06:29 PM rue_mohr: can I do the casting?
06:29 PM Tom_L: you should
06:30 PM Tom_L: you can
06:30 PM rue_mohr: yea, I have lots
06:30 PM Tom_L: and you may
06:30 PM rue_mohr: if I dont fall asleep
06:30 PM Tom_L: i'm goin early tonight
06:30 PM rue_mohr: still not 100% yet
06:30 PM Tom_L: up at 11pm
06:30 PM Tom_L: gone by 12
06:30 PM rue_mohr: to the moon?
06:31 PM Tom_L: 16-18 hr
06:31 PM rue_mohr: to canada!
06:31 PM Tom_L: no that would take longer
06:31 PM rue_mohr: not if you fly
06:32 PM Tom_L: i'd probably need more papers for that too
06:32 PM rue_mohr: just tell them rue sent ya
06:32 PM Tom_L: they might lock me up!
06:34 PM Tom_L: not sure i would fly anywhere right now
06:34 PM Tom_L: seems the numbers are on the rise again
06:34 PM rue_mohr: yea
06:34 PM rue_mohr: yep
06:35 PM rue_mohr: I got hit by somethingt
06:35 PM rue_mohr: thats why I been home
06:35 PM Tom_L: yeah i saw you didn't feel good
06:35 PM Tom_L: get a test?
06:36 PM rue_mohr: tommorow morning
06:36 PM rue_mohr: 2 day wait
06:36 PM rue_mohr: !
06:36 PM Tom_L: better test
06:36 PM Tom_L: i've done some 15 min ones but they're not as accurate
06:37 PM Tom_L: they'll swab your brain :)
06:37 PM rue_mohr: waiting to get in, not for results
06:37 PM Tom_L: really?
06:37 PM rue_mohr: yea
06:37 PM Tom_L: free test?
06:37 PM rue_mohr: that questions been going around
06:37 PM rue_mohr: yea
06:38 PM Tom_L: you can walk in about anywhere here and get tested
06:38 PM rue_mohr: i think they are getting a spike they weren't preppared for
06:41 PM aandrew: we had a guy from MA up in Toronto last week, no border issues
06:41 PM aandrew: actaully PCR and lateral flow tests are inaccurate in different ways
06:41 PM aandrew: (I know a bit about this)
06:41 PM rue_mohr: why coulnd't a processor be made from a DMA in a state machine?
06:42 PM aandrew: PCR tests can give false positives if they keep running the PCR cycles. Seems the "right" number of cycles is around 30-36
06:42 PM Tom_L: mine wasn't out of concern... a do not pass go unless you do test
06:42 PM rue_mohr: can a DMA load itself?
06:42 PM aandrew: the lower the cycle count = the more "severe" the infection
06:42 PM rue_mohr: no
06:42 PM aandrew: lateral flow testing tends to fail toward a false negative (poor sample collection, not enough fluid to let the assay do its job, etc.)
06:43 PM rue_mohr: but if you had two dma on a bug
06:43 PM rue_mohr: bus
06:43 PM aandrew: you generally have no control over the PCR cycle test since it takes a day or three and is done in a lab, and they often dont' tell you how many cycles they stopped at
06:43 PM aandrew: but lateral flow is cheap and fast and any idiot can do it, but you have to make sure you collect the sample properly
06:44 PM aandrew: I bought a 5-pack of lateral flow tests for $85, you can get one-offs at a lot of drug stores OTC in the US
06:44 PM aandrew: about $30
06:44 PM rue_mohr: one DMA could load a config for a transfer from ram to another dma
06:47 PM aandrew: rue_mohr: which architecture?
06:50 PM rue_mohr: x86, but with no cpu
06:50 PM rue_mohr: just two DMA
06:50 PM rue_mohr: I'm not sure how it would start
06:51 PM rue_mohr: but I think once it was going, it could sustain
07:07 PM Tom_L: so how do you kick start it?
07:35 PM aandrew: interesting...
07:35 PM aandrew: you'd have to poke it's setup registers with something then kick DRQ#, maybe a state machine from an eprom with an address counter driven by a yup
07:36 PM aandrew: but why
07:45 PM Tom_L: because rue
08:07 PM rue_mohr: hah
08:46 PM Tom_L: trying to find an irc clinet for android that will let me use libera
08:47 PM Tom_L: connected on one but it said i wasn't registered
09:16 PM rue_mohr: hmm
09:16 PM rue_mohr: they must have made a web portal
09:23 PM Tom_L: dunno if it will follow me or not
09:28 PM aandrew: Tom_L: not sure if it's available on android but "palaver" is pretty decent
09:28 PM aandrew: OSS too I think
09:29 PM aandrew: oof, lexan sheets got expensive
09:29 PM aandrew: amazon was actually cheaper than fastenal, homedepot/lowes/rona, but still pricey
09:58 PM aandrew: hm
09:58 PM aandrew: rue_mohr: around?
09:59 PM aandrew: I'm going to build a pair of comparators feeding an SR flipflop to act as a mosfet trigger; bascially a motor controller needs to occasionally very quickly ramp down a motor and that's causing the bus to rise and trip out the system
09:59 PM aandrew: so a mosfet which connects a 500R 5W resistor across the supply to bleed the voltage away
10:00 PM aandrew: 48V nominal, so say 60V set the FF, 55V reset the FF, something like that
10:00 PM aandrew: pair of voltage dividers feeding the comparators, no problem
10:01 PM aandrew: dual/quad comparator, no problem, SR FF no problem (even can be done with NAND gates if I want) and then a logic gate mosfet good for a few amps
10:01 PM aandrew: do you have a slicker solution?
10:02 PM rue_mohr: I'm here
10:04 PM rue_mohr: hmm, I could see something with a tl431 and a SCR, such the scr falls out at the right point in the discharge
10:04 PM rue_mohr: or
10:04 PM rue_mohr: use a 555 for the comparator
10:04 PM rue_mohr: and latch
10:05 PM aandrew: how do you turn off the SCR at the bottom of the window? SCR won't want to turn off until zero
10:05 PM rue_mohr: you design the current to fall off at that voltage below its threshold
10:05 PM rue_mohr: but 555 and IGBT
10:05 PM aandrew: ah yeah I see
10:06 PM rue_mohr: the scr thing is a lot of fiddly design work
10:06 PM rue_mohr: I like the 555 idea better
10:06 PM aandrew: yeah, that's why I was leaning toward the ff
10:06 PM aandrew: simple, independent levels adn failsafe
10:18 PM spline: ramp down a motor - is that like how a brake works on a spindle?
10:18 PM aandrew: yep
10:19 PM rue_mohr: oh Tom_L casting
10:20 PM rue_mohr: it didn't come out awesome
10:20 PM rue_mohr: some sand dropped out and a strange thing happened with the shrinkage
10:20 PM spline: isn't it like a big capacitor that energizes then uses magnetism?
10:21 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1200811.jpg
10:21 PM spline: aluminum casting?
10:21 PM spline: oh yeah im reading above
10:21 PM spline: iirc, aluminum shrinks 12%?
10:22 PM rue_mohr: 12! well that would do it
10:22 PM spline: friend from my makerspace got into doing some aluminum. He said control arms make the best material to cut up
10:22 PM rue_mohr: I figured about 5 or 6
10:22 PM spline: its a number I have in my head. I'm not sure why
10:22 PM spline: I'd think its also dictated by the alloy, but that's assuming you're going pure from ingots
10:23 PM spline: if I had to guess, watching how its made when they show engine blocks being cast before all the machining (really cool)
10:28 PM spline: what's the part you made for?
10:29 PM spline: rue_mohr, you're right. 6% - copper is 5% https://www.haworthcastings.co.uk/news/shrinkage-in-sand-casting
10:36 PM rue_mohr: part of a cnc machine
10:42 PM spline: looks almost like the ways or part of a vise
10:42 PM rue_mohr: its the XY junction for the ways
10:43 PM spline: interesting: was researching more on the cooling and found this
10:43 PM spline: "There is a technique called melt casting where you have a chilled spinning wheel and you pour on top that. Because aluminum has good thermal conductivity it is possible to cast aluminum based metallic glasses onto an aluminum wheel. This is the super cheapo way to do it but it is possible and if you don’t mind melting down your wheel every time there is a stoppage it works. I have only seen this done at labs where they make their own wheels, hav
10:43 PM spline: e a machine shop on site and are using custom equipment. The main reason they did this was that they had lots of aluminum and would recast the wheel blanks from the wreckage which was a lot cheaper then sending out for a copper wheel from a manufacturer."
10:44 PM spline: rue_mohr, ah gotcha - just reminded me of the knee on a knee mill
10:44 PM rue_mohr: I'm using box ways, with the ways made from 4"x1/4" cold rolled steel bar
10:48 PM spline: box is where it grabs 100% of it vs a dovetail?
10:48 PM spline: (had to research)
10:59 PM rue_mohr: well
10:59 PM rue_mohr: [----
10:59 PM rue_mohr: its an edge grab
11:23 PM spline: im use to dovetails on all the machines I've used