#garfield Logs
Sep 27 2020
#garfield Calendar
12:25 AM rue_mohr: so, odd
12:31 AM rue_mohr: the 6502, using its internal gates for an RC osc, does NOT like to reset below about 10Hz
12:33 AM rue_mohr: polprog, you cant jukt like it, can you PLAY it?
12:34 AM polprog: i can, but you literally tweeted it just the second i woke up
12:34 AM rue_mohr: so whats the delay!
12:34 AM rue_mohr: :)
12:34 AM polprog: plays right on the phone
12:34 AM polprog: takes a bit to boot up the labpc
12:34 AM rue_mohr: k, your phone always works tho
12:34 AM rue_mohr: ugh, ok
12:37 AM polprog: Yep, i can play it on firefox on the debian box
12:37 AM rue_mohr: I dont get it
12:37 AM rue_mohr: the difference is that the tail isn't appended
12:37 AM rue_mohr: but the tail is in the same format as that video that works
12:37 AM polprog: ha, the first video doesnt play
12:38 AM rue_mohr: yea, so why does the tail stop the video from playing
12:41 AM polprog: ok, gotta eat breakfast and go to the market
12:41 AM rue_mohr: thanks
12:45 AM rue_mohr: I dont get it
12:46 AM rue_mohr: ok, joule theif!
12:50 AM rue_mohr: http://cs.yrex.com/ke3fl/htm/JouleThief/JouleThief.htm
01:37 AM rue_shop1: wow
01:37 AM rue_shop1: you get the transformer polarity right and that really goes
04:10 AM rue_mohr: polprog, that didn't take ya long
04:23 AM rue_mohr: polprog, thats an awefull lot of 7 segment displays
04:27 AM rue_mohr: keyboard/display interface
04:29 AM rue_mohr: FIFO for the keyboard, incase you cant respond to the user for a few key presses
04:30 AM rue_mohr: they did something funkey with the display
04:30 AM rue_mohr: that chip cant operate that much display
04:31 AM rue_mohr: the app note doesn't mention anything about expanding it
04:33 AM rue_mohr: or they just used it for keybaord
04:41 AM polprog: hmm
04:41 AM polprog: yeah, its a compleat z180 system
04:41 AM polprog: just add eprom
04:42 AM polprog: noone seems to have 29c040
04:42 AM rue_mohr: hmm, whats the php syntax for loop N times...
04:42 AM rue_mohr: oh, I do
04:42 AM rue_mohr: mail?
04:42 AM polprog: the guy that usually has the ICs only had one today
04:42 AM rue_mohr: I think I do
04:42 AM polprog: he has a stock of them but he didnt take much
04:42 AM rue_mohr: :/ it would only take like 6 eons to get to ya
04:43 AM polprog: dosfox needs 4 of them, so i figured i could buy 10 and just send him 4
04:43 AM rue_mohr: k
04:43 AM polprog: big eproms like that would come in handy. i still want to improve my sampler
04:44 AM polprog: 512k*8bit, at 8khz sampling rate would give me 64 seconds of sound
04:45 AM polprog: awesome
04:46 AM polprog: two would be enough
04:46 AM polprog: for 16 short samples
04:46 AM rue_mohr: what are you going to make it say?
04:46 AM polprog: dunno, maybe load some drum kit
04:47 AM polprog: or some atari speech samples
04:47 AM polprog: or fill one with a looped rave track, and make a noise machine
04:47 AM polprog: eprom+dac+speaker amp
04:47 AM polprog: press button, receive rave
04:48 AM rue_mohr: I wonder if you could store more/less/same as 1 bit analog
04:50 AM polprog: its easier to pump it out as 8 bits paralell
04:50 AM polprog: https://youtu.be/eKY8qpPmGnk skip to 2:56
04:50 AM polprog: that sample, looped
04:50 AM polprog: :D
04:50 AM rue_mohr: but all you need is a RC lowpass for 1 bit
04:51 AM polprog: hmm
04:51 AM rue_mohr: you have 1 tracks on 1 chip :)
04:51 AM polprog: 8 tracks on 1 chip :)
04:51 AM polprog: like a tape machine
04:52 AM rue_mohr: use a 8:1 selector to choose the track
04:52 AM rue_mohr: I dont know what the data storage is like
04:54 AM polprog: its a regular eprom, 512k x 8
04:54 AM polprog: i only have one so far
04:54 AM polprog: i still dont have the right counters though
05:23 AM rue_mohr: 6502
05:23 AM rue_mohr: 16 bits
05:23 AM rue_mohr: or a 6809, but they aren't as fast
05:23 AM rue_mohr: fpga
05:25 AM rue_mohr: ok, I got more code done for the jukebox
05:25 AM rue_mohr: need sleep!
05:36 AM Tom_L: naw
08:15 AM aandrew: morning
08:20 AM Tom_L: hi
08:47 AM polprog: oh nice. the home internet shat the bed
08:47 AM polprog: anyway, i made a toy vu meter
11:34 AM rue_bed: k
11:42 AM Tom_L: l
11:49 AM aandrew: I bought a little PoE IP camera (https://www.amazon.ca/gp/product/B07YCDW3N3), $50, has (manual) zoom lens, PoE, is pretty small and does ONVIF/direct streaming
11:49 AM aandrew: I ripped out the internal IR cut filter and of course everything is pink, I discovered that the shitty plastic protective lens cover also blocks some IR
11:50 AM aandrew: whenever the IR pass filters arrive will see how well this will work at capturing license plates
11:50 AM aandrew: it is actually quite nice quality video, the zoom lens is also decent (2.8-12mm)
12:17 PM polprog: nice
12:18 PM polprog: now i should buy 5 identical meters and make an analogue spectrum analyzer
12:19 PM rue_mohr: or go led?
12:19 PM rue_mohr: hmm
12:19 PM aandrew: haha
12:19 PM aandrew: analog spectrum analyzer would look pretty slick with those longer vertical meters
12:19 PM rue_mohr: only 5 tho?
12:20 PM rue_mohr: hmm
12:20 PM rue_mohr: wait
12:21 PM rue_mohr: whats dbu?
12:21 PM rue_mohr: not dbm?
12:29 PM rue_mohr: ok
12:30 PM rue_mohr: today is pillar rocks, power supply heatsink, groceries, order school books, and jukebox
12:30 PM rue_mohr: I have 12 hours
12:43 PM polprog: dbu is some weird audio unit, +4 dbu is smehing like 1khz sine 1.2vpp
12:43 PM polprog: i dont remember
12:43 PM polprog: and of there is zillion of standards, consumer dBu is different than proffesional dBu and so on
12:44 PM polprog: of course there*
12:45 PM polprog: hmm, i have 4 identical 0-3dB ones
12:45 PM polprog: that would be cool
12:45 PM polprog: id need to develop and etch 4 of these units with a bandpass in the front
12:46 PM polprog: this is basically a stereo sum that goes to the opamp rectifier, that then goes straight to the meter movement
12:47 PM polprog: pretty simple but takes a shitton of resistors to get a virtual ground at 2.5V to be able to run it from 5v
12:50 PM polprog: mmm, internet outage in my area
12:50 PM polprog: i gotta IRC from the phone >:(
12:51 PM Tom_L: got a good data plan?
12:54 PM polprog: yeah, its fine
12:54 PM polprog: i also have a nice bluetooth keyboard
12:54 PM polprog: :)
12:55 PM aandrew: dBu = dBuV - basically comparing against 1uV not 1mW
01:05 PM rue_mohr: ok
01:05 PM rue_mohr: uV...
01:05 PM rue_mohr: oh in deviation of 1.2V
01:09 PM aandrew: bleh
01:09 PM aandrew: I hate how image sensors and lenses are specified
01:09 PM aandrew: I htink I kind of got it now
01:10 PM aandrew: everything is in relation to 35mm which is "full frame". sensors are measured in some fraction of an inch, but it's goofy. Like 1/2.7" or 1/1.3" -- the smaller the denominator the bigger the sensor
01:11 PM aandrew: and the lenses are all specified in what kind of sensor area they're able to cover, so a 1/2.7" lens can work with a 1/3" sensor because the focal plane of the lens is larger than the sensor. If that's not the case then you get the black ring around the edges
01:12 PM aandrew: Then the 'mm' rating is a measure of captured image width. still not 100% sure how it relates but the smaller the mm the more widescreen the image
01:13 PM rue_mohr: I have a huge box of lenses
01:13 PM rue_mohr: I need to make a light table and sit down to understand it all
01:13 PM aandrew: then there's the f-stop rating or ratio, so f/1.4 or 1:1.4 is a measure of how much light the lens lets in. ratios closer to 1:1 let in more light and are generally physically bigger lenses
01:14 PM aandrew: yeah I have a small collection of mostly wide-angle-ish lenses (anywhere from 1.3mm to 6mm)
01:14 PM rue_mohr: [today is pillar rocks, power supply heatsink, groceries, order school books, and jukebox]
01:15 PM aandrew: and they're all M12 mount (12mm dia, 0.5mm pitch) and generally speaking in the 1/2.5" to 1/2.8" range, so for smaller sensors
01:15 PM aandrew: although a bunch of these are also identified as "MP" ratings which to me is ridiculous. the lens doesn't determine that
01:16 PM aandrew: like wtf is a 5MP lens, it's meaningless
01:16 PM rue_mohr: so, there should be 2 focus distances, right?
01:16 PM aandrew: I have no idea. :-) I thought you did some security system work, I was hoping you'd know
01:16 PM rue_mohr: inf |) Xmm
01:16 PM rue_mohr: oh god I made a cheat sheet
01:17 PM rue_mohr: its only about working out the view width tho
01:17 PM aandrew: well no, the mm rating, along with the sensor size, determines the actual image capture angle
01:17 PM rue_mohr: no, I mean the focus distance in mm for an actual glass component
01:18 PM aandrew: oh, I am not sure. I'm guessing that is encoded in to that mm as well
01:18 PM aandrew: i.e. a 220mm zoom can't focus properly on anything very close at all
01:18 PM aandrew: but an 8mm zoom can, although I doubt it can focus 8mm from the surface of the glass
01:20 PM rue_mohr: I need some kinda breakfast/lunch
01:22 PM aandrew: yeah Im gonna bbq some hot dogs momentarily
01:25 PM rue_mohr: funny, perl hilight mode works quite well on php
01:25 PM aandrew: https://www.ni.com/en-ca/support/documentation/supplemental/18/calculating-camera-sensor-resolution-and-lens-focal-length.html goes into it a bit
01:25 PM aandrew: focal length vs working distance
01:26 PM aandrew: and I also think I just figured out why the one camera has vignetting, I am pretty sure the lens I put in it last year was 1/2.5 and the sensor (just looekd it up) is 1/2.8
01:27 PM rue_mohr: which freaking tab has the javascript intermittently locking up firefox....
01:29 PM rue_mohr: arg, I think it just killed all my tabs
01:29 PM rue_mohr: I did kill -9
01:29 PM rue_mohr: crap
01:30 PM rue_mohr: arg
01:30 PM rue_mohr: ok, breathe
01:41 PM rue_mohr: hahahhaha
01:41 PM rue_mohr: they want me to buy $600 in books they will never actaully use in the course
01:49 PM Tom_L: some of the "books' we had to buy were just an access code
01:49 PM Tom_L: find them on ebay etc
01:55 PM rue_mohr: just asked one of the guys out of the course, says they dont even use them in the online course
01:55 PM rue_mohr: so OK!
01:56 PM Tom_L: it's completely online?
01:56 PM rue_mohr: yep
01:56 PM rue_mohr: oh wow, drying my shoes after yesterday would have been an awesome idea
01:56 PM Tom_L: i wouldn't get em either unless it has an access code you gotta buy
01:58 PM aandrew: chrome has a nice task manager to help with that
01:58 PM aandrew: I fucking hate when they want you to do that (buy shit you don't use)
01:59 PM aandrew: now when *I* buy shit I don't use it's one thing, but not when others make me do it :-)
02:06 PM Tom_L: it's a concious choice. there's a difference
02:48 PM polprog: hmm, so I have this 2716 eprom that is full of zeros
02:48 PM polprog: (programmed it all zeros long time ago)
02:49 PM polprog: and when i put it to the desk lamp it starts to fill with ones
02:49 PM polprog: ive gotta measure how random that fill is..
02:49 PM polprog: its also not very light sensitive, it really takes strong light to temporarily flip the bit. maybe i could undervolt it
02:50 PM polprog: whitequark did some research on undervolting eproms
02:50 PM polprog: ideally i would have it sensitive enough to strap a lens to it, and then you know what happens
02:51 PM polprog: i also realized i have some 27c1001, nice
02:51 PM polprog: but they are completely not sensitive to light.
02:58 PM aandrew: it's my understanding that whitequark's work was about recovering marginally programmed EPROMs through undervolting so that the threshold voltages were not so high
03:00 PM polprog: yeah, but it might he handy to read it
03:01 PM polprog: it was about recovering eproms where the programmed bits were "weak"
03:01 PM aandrew: yep
03:01 PM polprog: and i think they (?) found out that thr output drivers can oscillate for a while if the charge on the cell was weak.. iirc
03:02 PM polprog: and so undervolting lowered some rise times iirc, that helped stabilize the output drivers
03:02 PM polprog: i glanced thru the twitter thread
03:03 PM polprog: it was pretty amazing
04:38 PM aandrew: lol I have found 150mm M12 mount lenses
04:38 PM aandrew: that is insane
04:38 PM aandrew: these things are like 5" long
04:39 PM aandrew: I can not expect that they'd have good image quality, they must need a LOT of light
04:39 PM aandrew: 2 degree FOV
04:41 PM aandrew: ok this is silly now, 300mm lenses, 1 degree FOV
04:42 PM aandrew: 16mm diameter, 82mm long
06:09 PM zhanx_workshop: so hot out... ugh
06:13 PM Tom_L: wind picked up and cooled down alot here
11:09 PM rue_mohr: ok, $300 in groceries later
11:11 PM rue_mohr: so, I have about 150 cut stones
11:11 PM rue_mohr: I wont be able to cut more with the wet saw
11:11 PM rue_mohr: so I hope thats enough
11:19 PM rue_mohr: Tom_L,
11:19 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1170454.jpg <-- thats the wet saw
11:19 PM rue_mohr: I have to wrap it up to go back
11:36 PM Tom_L: 300 should last a while
11:36 PM Tom_L: ahh that's a big one
11:37 PM Tom_L: nice commercial saw
11:54 PM rue_shop1: it saved a lot of time
11:58 PM Tom_L: yeah those cut good
11:58 PM Tom_L: water reservoir?
11:59 PM Tom_L: looks like it
11:59 PM Tom_L: i see the hose going to the blade nwo
11:59 PM Tom_L: now