#garfield Logs

Oct 27 2021

12:30 AM rue_shop3: ok, I got the startup shot of the oscillator I wanted
04:37 AM Tom_itx is now known as Tom_L
10:08 AM rue_mohr: morning
10:09 AM rue_mohr: the oscillator workes like I thought it did
05:16 PM aandrew: wow
05:16 PM aandrew: I have an unopened box from Digikey containing a 1206 resistor kit. The date code is 2005!
05:20 PM aandrew: 60 different values: 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82 in decades 1, 10, 100, 1k, 10k and 100k
05:20 PM aandrew: that'd be 72 values though, so a few must be skipped
05:22 PM aandrew: ah, decades 1,10,100,1k,10k and only 1M in 100k
05:22 PM aandrew: that's 60
05:26 PM aandrew: that sounds like E12
05:28 PM rue_mohr: :)
05:29 PM aandrew: still trying to find the right set of values for my resistor book without going overboard or creating problems in future when I get some inbetween value
05:29 PM aandrew: 1% is just too many values
05:30 PM rue_mohr: hmm, I'm not sure what was in my china kit
05:39 PM aandrew: wtf
05:39 PM aandrew: 47.0k is not in E92?
05:40 PM aandrew: it's 1%, not 0.5%
05:40 PM aandrew: nope, it's E192
05:43 PM aandrew: ugh this is sad
05:43 PM aandrew: so many 1% values are E192
05:44 PM aandrew: 12, 22, 33, 47, 56...
05:45 PM aandrew: it loks like E24+E92 seems to be the sweet spot
05:45 PM rue_mohr: :)
06:05 PM Tom_L: driver is mostly wired
06:54 PM aandrew: heh
06:54 PM aandrew: https://docs.google.com/spreadsheets/d/1hk5XsZqNqLzDbesFZj9OMrD5GbhzRIgs0_S0Dcg-X_s/edit?usp=sharing
06:55 PM aandrew: I have 99 unique resistor values in my collection
06:55 PM aandrew: not including high current/shunt resitors which I didn't pull in
07:29 PM aandrew: woo
07:29 PM aandrew: figured it out
07:30 PM rue_mohr: ?
07:30 PM aandrew: the 35mm film binder sheets I am going to use have seven rows per page
07:30 PM rue_mohr: sorting them?
07:30 PM aandrew: that's 7 decades per "row" in the spreadsheet
07:30 PM rue_mohr: you know I use a 35mm eh?
07:30 PM aandrew: so the entire page has 1x to 100kx for a particular value like 51
07:31 PM aandrew: if I don't have any in a row (no green in the row in the spreadsheet) then I just don't populate it in the binder
07:31 PM aandrew: but if I get one, I insert the page in the right place and I don't lose sorting order
07:31 PM rue_mohr: huh
07:31 PM rue_mohr: parpendicular index, cute
07:31 PM aandrew: basically instead of each page being a set of values that is "long", it is "wide" instead
07:31 PM aandrew: yeah
07:31 PM aandrew: I'm REALLY happy with that
07:31 PM aandrew: it preserves sort order and doesn't leave huge gaps
08:23 PM aandrew: so 100 unique values and with the spread I have that's 65 pages, but I still need to separate/organize that by physical size
08:24 PM aandrew: I need to order more of these damn sleeves. amazon pricing is insanely stupid, Henry's (where I got these) is like $15 for 25
08:26 PM aandrew: then lather, rinse, repeat for caps and stnadard footprint inductors/ferrites
08:30 PM rue_shop3: I'm doing an etchant test on the UV nail polish
08:31 PM aandrew: yeah you and tara are going wild with that
08:35 PM rue_mohr: I suggested it to her, I got all the supplies and didn't give it a try yet
08:35 PM rue_mohr: she's doing an amazing amount of work to try and get it going
08:44 PM aandrew: yes, it seems like an unbelivable amount of work to get going, I wonder if a regular photo resist method wouldn't work a lot better
08:44 PM aandrew: we used to spray the bare boards with the photosensitive chemical, expose and develop in electronics class
08:45 PM aandrew: IIRC it was very straightforward and the biggest issue we had was dust contamination
08:45 PM aandrew: sure seems a fuckload easier than what I see you guys tweeting about, and with better results
08:45 PM aandrew: IIRC it was a bottle of the photoresist spray, a bottle of developer and (distilled/deionized?) water
08:46 PM aandrew: that was a bunch of kids mostly goofing off in school too, not someone actually trying to do something
08:48 PM aandrew: https://www.amazon.ca/MG-Chemicals-Positive-Developer-Bottle/dp/B005T8QLCY is the developer
08:49 PM aandrew: looks like the photoresist spray has gone away, but this film is everywhere and cheap: https://www.amazon.ca/Portable-Resolution-Photosensitive-Production-Photoresist/dp/B07LB2CBQL
08:50 PM aandrew: https://www.youtube.com/watch?v=VkQroiEJBMs looks like the process we used
08:52 PM aandrew: yeah it seems like everyone has dropped the photoresist spray and either uses dry film or pre-senstized boards
10:51 PM rue_mohr: yea, but its chemical hell and $$$$
10:53 PM rue_mohr: if there is a way to make UV resin or uv nail polish work, it would be awesome
10:55 PM Tom_L: i may still have some UV paint
10:55 PM Tom_L: that white lettering on the blue case was UV
10:56 PM aandrew: rue_mohr: compared to you playing with nail polish, acetone and a lot of mechanical friction?
10:56 PM rue_mohr: did you ever photomask-cure it?
10:56 PM Tom_L: me?
10:56 PM rue_mohr: yea
10:56 PM aandrew: two chemicals, or one chemical and dry film seems way less hassle than everything you two are going through
10:57 PM rue_mohr: aandrew, I also dont think the photo stuff ages well on the shelf
10:57 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/boards/USBTiny_Mkii/silkscreen/silk_batch_cure.jpg
10:57 PM rue_mohr: I have that speedball kit I STILL havn't tried
10:57 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/boards/USBTiny_Mkii/silkscreen/silk_batch.jpg
10:57 PM aandrew: it looks like positive photo developer is just NaOH
10:57 PM rue_mohr: hmm
10:58 PM rue_mohr: I hate it when they do that
10:58 PM rue_mohr: "its table salt, but we wont tell you " (I know NaOH isn't, but point)
10:58 PM aandrew: yep... MG Chemicals positive photoresist is 95% water, 5% NaOH. That's it
10:59 PM Tom_L: getting a following error on the A axis
10:59 PM Tom_L: haven't quite figured it out yet
10:59 PM aandrew: er not positive photoresist, positive developer
11:00 PM rue_mohr: back in 2002 a guy told me you couldn't get the photosensitive stuff in bottle form anymore
11:00 PM aandrew: the photoresist is significantly more complicated
11:00 PM aandrew: yeah I can't find it
11:00 PM aandrew: only the dry film
11:00 PM rue_mohr: he said to spin it
11:00 PM aandrew: I can't even find that, at least not unless I go to more professional sources, with respective pricing
11:01 PM rue_mohr: I dont want to buy specialty produts from anyone, markup is too high
11:01 PM Tom_L: go to a sign company and ask for a sample of UV paint. take a babyfood jar with you
11:01 PM Tom_L: i did.
11:01 PM Tom_L: it worked
11:01 PM rue_mohr: 3d printer resin
11:01 PM aandrew: rue_mohr: sure, but dry film is available everywhere and cheap, and it looks like the developer is also super cheap
11:01 PM rue_mohr: I have some uv solder mask and a bunch of UV nail polish
11:01 PM aandrew: looks like that might be way way easier and better results
11:02 PM rue_mohr: but its kinda thick and seems to be scattering the UV internally
11:02 PM Tom_L: does it cure?
11:02 PM rue_mohr: yes, but
11:02 PM Tom_L: mine are fishtank uv bulbs
11:02 PM rue_mohr: you cant get a sharp edge with a thick coat
11:02 PM Tom_L: put off alot of uv
11:02 PM Tom_L: you can smell it
11:02 PM rue_mohr: because it internally seems to scatter the UV
11:02 PM Tom_L: ozone
11:02 PM rue_mohr: and, cant clean it off
11:02 PM rue_mohr: acetone wont touch it
11:03 PM rue_mohr: so I had to scrape off the resist after the etch
11:04 PM rue_mohr: here tom
11:04 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210430.jpg
11:04 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210434.jpg
11:04 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210435.jpg
11:04 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210436.jpg
11:04 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210440.jpg
11:04 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210443.jpg
11:04 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210444.jpg
11:04 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210447.jpg
11:04 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1210448.jpg
11:07 PM Tom_L: power traces
11:10 PM rue_mohr: the focus on the uv laser was pretty wide
11:11 PM Tom_L: find some old fishtank uv flourescent bulbs
11:11 PM Tom_L: i got those free + shipping
11:11 PM Tom_L: they have to change em out every so often
11:12 PM Tom_L: or even in a walmart or box store they have them hanging around the entrance sometimes
11:12 PM rue_mohr: not the problem tho
11:12 PM rue_mohr: If the uv light scatters while its IN the layer of uv paint, the only solution is a thinner coat
11:13 PM rue_mohr: I tired to thin it down with acetone but it didn't work at all
11:13 PM rue_mohr: I have all sorts of flourescent lights
11:13 PM rue_mohr: but another twitter person tried a germicidal UV lamp and it didn't work, seem to be the wrong spectrum
11:14 PM rue_mohr: those leds work FAST
11:15 PM Tom_L: i dunno about the fishtank ones but that's what they're used for and mine work like a champ
11:58 PM rue_mohr: huh, I probably have pernicious anemia... dang