#garfield Logs

Aug 01 2020

12:42 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1160758.jpg
12:48 AM rue_mohr: total distraction
04:56 AM polprog: nice memory
11:24 AM rue_mohr: can I drive it tho?
11:25 AM Tom_L: you ever see those in equipment?
11:26 AM rue_mohr: not even in RF stuff
11:26 AM Tom_L: i have
11:26 AM Tom_L: core memory?
11:26 AM Tom_L: yeah
11:29 AM Tom_L: https://upload.wikimedia.org/wikipedia/commons/d/da/KL_CoreMemory.jpg
11:33 AM rue_mohr: gee, like 5 new followers cause I did a 16 bit core module!?!?!
11:33 AM rue_mohr: people are crazy
11:43 AM Tom_L: fact
11:44 AM rue_mohr: quite hard to thread those
11:44 AM rue_mohr: that one on the wiki is a '4 wrie' which is harder
11:57 AM polprog: i got 4 new followers cause i posted a silly pitcher under another silly pitched
11:57 AM polprog: er*
11:57 AM polprog: twitter is weird
11:58 AM polprog: rue_mohr: mind putting these tapes aside?
12:20 PM rue_mohr: well, I dont want to get rid of them, I have the two drives too
12:20 PM rue_mohr: LVD scsi
12:20 PM rue_mohr: you want?
12:20 PM rue_mohr: I dont
01:06 PM polprog: sure
01:06 PM polprog: ill find something to send you back ;) i dont know what you need
01:19 PM Tom_L: i bet he needs breakfast
01:22 PM polprog: we can arrange that
02:57 PM rue_shop1: toms right and its 1:00
03:59 PM aandrew: did you lose your coffee cup again?
03:59 PM aandrew: rue_shop1: by the way I *loved* your play by play on the core memory construction on twitter yesterday
03:59 PM aandrew: that was hilarious
04:00 PM aandrew: "each step is twice as hard as the last step!"
04:56 PM rue_mohr: tea
04:56 PM rue_mohr: aandrew, funny thing LOTS of people responded to that core memory thing
04:56 PM rue_mohr: I didn't expect much interest
04:57 PM aandrew: it's unusual and interesting
04:57 PM aandrew: you also present it with humour which I think a lot of people respond to as well
04:57 PM aandrew: cool tech that's not dry and unapproachable
05:00 PM rue_mohr: there was a lot of "rue says wire goes thru here!" "core says, no..."
05:00 PM rue_mohr: :)
05:00 PM rue_mohr: its true, each step is twice as hard
05:01 PM rue_mohr: I turned around to slap a mosquito, and snagged the wire that still had the 12 remaining cores after the first row
05:01 PM rue_mohr: I heard them scatter across the shop.. :(
05:01 PM rue_mohr: found 2
05:02 PM rue_mohr: luckily, the first bridge with the first 4 cores was ok
05:17 PM polprog: still making the core memory module?
05:17 PM rue_mohr: na I need to figure out a driver for it
05:17 PM polprog: want a distraction/tool?
05:17 PM rue_mohr: I need to know what current it takes to flip it
05:17 PM rue_mohr: oh you know I'm a sucker for distractions
05:17 PM polprog: https://polprog.net/rozne1/ircjunk/various/transistor_pair_picker.jpg
05:18 PM rue_mohr: but I need to work out the reverse breakdown of an led
05:18 PM polprog: im.. stuck here for another week with no lab access :P
05:18 PM polprog: but i found a pencil and a piece of paper
05:18 PM rue_mohr: how much stuff do you have at home?
05:18 PM polprog: as in?
05:19 PM polprog: i mean my home lab
05:19 PM polprog: im in the UK now, with family
05:19 PM rue_mohr: oh, your stuck away from home
05:19 PM rue_mohr: with family, how terrible
05:19 PM polprog: its manageable
05:19 PM polprog: if only they shut off the tv when noone is watching
05:20 PM polprog: so i came up with that just a moment ago
05:36 PM rue_shop1: :)
05:36 PM polprog: got it working?
05:36 PM rue_shop1: 84V to reverse break down an led
05:36 PM polprog: haha
05:37 PM polprog: is it destructive?
05:37 PM rue_shop1: ...
05:37 PM rue_shop1: no, its ok
05:37 PM rue_shop1: I dont think my tester applies much current
05:38 PM rue_shop1: but I need to make a bond-wire-popper
05:39 PM rue_shop1: for those 8x8 arrays
05:39 PM rue_shop1: I need it to blow open, not short
05:39 PM polprog: hmm, what for?
05:39 PM rue_shop1: programming 8x8 LED arrays with data
05:39 PM rue_shop1: by opening the bond wires on the diodes I dont want connected
05:39 PM rue_shop1: OTP
05:40 PM polprog: hmm
05:40 PM polprog: what 8x8 arrays? usual plasticky ones or some older stuff?
05:40 PM rue_shop1: I need to do it without blowing other parts of the array
05:40 PM rue_shop1: https://www.aliexpress.com/item/32823415893.html
05:41 PM rue_shop1: since I'm kinda on obscure memory anyhow
05:41 PM polprog: i doubt it will be easy to blow out the bondwires without blowing out the leds
05:42 PM polprog: id say it would be easier to do the opposite
05:42 PM polprog: take a led array
05:42 PM rue_shop1: the problem is that the dies probably fail shorted
05:42 PM polprog: blow out some leds
05:42 PM polprog: then to read it place it under a camera and light up all of them
05:42 PM rue_shop1: wait.. that said
05:42 PM rue_shop1: hmm, what I need is to come up with some data to program
05:42 PM Tom_L: how much current do you think it takes for those cores?
05:43 PM Tom_L: and how often do you refresh?
05:43 PM rue_shop1: I also need to work out the "flip current" of those cores in that memory
05:43 PM rue_shop1: Tom_L, you never refresh
05:43 PM rue_shop1: ever
05:43 PM rue_shop1: its non-volatile
05:43 PM rue_shop1: completely
05:43 PM Tom_L: i couldn't remember
05:43 PM Tom_L: i thought they did
05:43 PM rue_shop1: but you have to reset a bit to read it
05:43 PM rue_shop1: so if you read a 1 you have to re-write it after
05:43 PM Tom_L: maybe that was it
05:43 PM rue_shop1: :)
05:44 PM Tom_L: it's not like i messed with any last week
05:44 PM rue_shop1: I'm expecting maybe an amp?
05:44 PM rue_shop1: I have to make it a FAST pulse
05:44 PM polprog: noo. too much
05:44 PM polprog: id say 200mA max
05:44 PM rue_shop1: really?
05:44 PM rue_shop1: well this will be interesting
05:44 PM polprog: i think..
05:44 PM rue_shop1: so, what do I program into a 8x8 array?
05:45 PM polprog: in theory i just finished phys 2 where mangetism was a big thing but i dont remember
05:45 PM rue_shop1: 7 segment data?
05:45 PM polprog: a smiley?
05:45 PM rue_shop1: its 8, 8 bit words
05:45 PM rue_shop1: I could make a state machine
05:45 PM Tom_L: https://sites.google.com/site/wayneholder/_/rsrc/1280545101151/one-bit-ferrite-core-memory/Core%20Test.png
05:45 PM polprog: http://ruemohr.org/~ircjunk/rockers/images/ruesrock.jpg this ;)
05:45 PM Tom_L: there you go
05:46 PM rue_shop1: oh 754410
05:46 PM rue_shop1: polprog, would you like to add a rock?
05:46 PM rue_shop1: you have to find a rock, draw eyes on it, and take a picture
05:46 PM polprog: sure
05:46 PM rue_shop1: its proof your a do-er and not just a talk-er
05:47 PM polprog: didnt you have enough proof already :P?
05:47 PM polprog: allright.. ill be on the lookout for cool rocks
05:47 PM Tom_L: https://cdn.hackaday.io/images/3973181461143571760.png
05:47 PM Tom_L: somebody already did it
05:47 PM rue_shop1: totally, but its a badge :)
05:47 PM polprog: :)
05:48 PM rue_shop1: Tom_L, I know, but now that I build the array, I'd like to use it
05:48 PM rue_shop1: I want to know what the data is in it now
05:50 PM rue_shop1: hmm
05:51 PM rue_shop1: I could do a FSM that repeats 867-5309 on a seven segment display
05:51 PM Tom_L: https://lh3.googleusercontent.com/proxy/VEHGoUrMZYSw6ky8mmx-YtR0nTmyUo3Q0VOM8vhLWaQtLQs8FfV3NSFUKlsuXNPPTgsX5HNKYslty0R0NSAVSNfK26KOZki-E0qR4g
05:51 PM rue_shop1: yup
05:51 PM Tom_L: i've seen that sketch before
05:51 PM rue_shop1: I'm told to make the current thu each less than half what it takes to flip the core
05:52 PM rue_shop1: apparently there is a LOT of memory core documentation around
05:52 PM polprog: whats up with that song, the 867-5309 came up for the second time on irc today
05:52 PM Tom_L: who came up with it anyway? bell labs?
05:53 PM rue_shop1: its ooold
05:53 PM rue_shop1: heh
05:53 PM rue_shop1: polprog, maybe that means I should
05:53 PM Tom_L: polprog, you didn't call it the first time
05:53 PM polprog: Tom_L: there is no area code
05:54 PM polprog: should i try 1-800 ;P?
05:57 PM rue_shop1: ran out of 1-800, its 1-877 now
05:57 PM rue_shop1: ok, to make that would take 4 chips
05:58 PM polprog: nighters
05:58 PM rue_shop1: 3->8, data latch, 555, 7 segment decoder
06:13 PM rue_shop1: polprog, wait, stay up all night and play
06:15 PM Tom_L: got my new calipers today
06:16 PM Tom_L: had to give my kid his back after he gave em to me since he got a new job
06:16 PM rue_shop1: :)
06:17 PM Tom_L: rotary head.. monday
06:17 PM rue_shop1: didyou get some from china?
06:17 PM Tom_L: they are china but mitutoyo
06:17 PM rue_shop1: k
06:17 PM Tom_L: they're better than average but not super good mitutoyo
06:17 PM rue_shop1: I made sure to get mid-priced ones last time, and their ok
06:18 PM Tom_L: i got a cheap pair i leave in the garage
06:18 PM Tom_L: both are 8"
06:21 PM rue_shop1: ok, so, 74xx138 drives ative low
06:21 PM rue_shop1: is there one that drives high?
09:44 PM Tom_L: new calipers, new box: http://tom-itx.no-ip.biz:81/~webpage/cnc/calipers/mitutoyo.jpg
11:55 PM rue_mohr: wood?