#garfield Logs

Nov 04 2023

10:04 AM polprog: aandrew: im doing it to see how much i can push C
10:17 AM polprog: if i need it to be real fast ill probably write the core routines in inline asm for example
12:26 PM rue_mohr: hi
12:26 PM Tom_L: lo
12:26 PM rue_mohr: :]
12:26 PM Tom_L: :[
12:27 PM rue_mohr: see if I can avoid spending all day on this CPLD board
12:28 PM rue_mohr: I'm working on redoing the silkscreen
12:28 PM rue_mohr: turn off all the part refrences and add back whats needed
12:28 PM rue_mohr: but this one is crazy tight
12:29 PM rue_mohr: oh
12:29 PM rue_mohr: huh
12:29 PM rue_mohr: this might be easier to use upside down
12:29 PM rue_mohr: I didn't think of that...
12:29 PM rue_mohr: all the interface stuff is on the wrong side
12:30 PM rue_mohr: dont want to re-arrange it now...
12:38 PM rue_mohr: oh I better do a run test on the generator
12:39 PM aandrew: Tom_L: hallowe'en is over. your vampire emoji is dated now
12:40 PM aandrew: rue_mohr: I saw something really interesting on mastodon... making PCBs with photo resist and a resin printer. it's so obvious in hindsight I'm embarassed to not have thought of it
12:40 PM aandrew: basically photo resist treated PCB exposed for like 90s = perfection
12:40 PM rue_mohr: I thought of it a long time ago, but dont have one
12:41 PM rue_mohr: I think I asked a buddy with one if we could try it
12:41 PM aandrew: he also tried putting bare (untreated) PCB and using 1 layer of resin to "print" the trace patterns on the bare PCB and etch that, but it didn't work well at all, but he also did not actually clean his PCB
12:41 PM rue_mohr: he's been too busy
12:41 PM aandrew: I bet it would work better if he actually used clean copper
12:41 PM aandrew: I have one now
12:41 PM rue_mohr: er, wait, hu
12:41 PM aandrew: and it doesn't surprise me that you'd have thought of it ages ago
12:41 PM rue_mohr: oh
12:42 PM rue_mohr: oh I was going for the print a layer thing
12:42 PM rue_mohr: huh
12:42 PM rue_mohr: oh
12:42 PM rue_mohr: still have to deal with all the chemicals then, bleck
12:43 PM rue_mohr: cool tho
12:43 PM aandrew: "all" the chemicals? ammonium persulfate and isopropyl alcohol?
12:43 PM rue_mohr: the developer and wash etc etc
12:43 PM rue_mohr: for the pretreated boards
12:43 PM aandrew: there's also water washable resin (I have this) but it's not worth it, just use the regular iso cleaning one
12:43 PM aandrew: well developer is just sodium hydroxide
12:44 PM rue_mohr: then there is the $$$ of the pre-sensitized baords
12:44 PM rue_mohr: how much are those worth now?
12:44 PM rue_mohr: last prices I saw for plain clad were insane
12:46 PM aandrew: https://www.youtube.com/watch?v=RudStbSApdE&feature=youtu.be
12:46 PM aandrew: $14 for 30x500cm iron on foil
12:49 PM rue_mohr: hmm presensitized for $20/3"x5"
12:52 PM rue_mohr: he etched it backwards...
12:54 PM rue_mohr: 1.30/inch^2
12:59 PM rue_mohr: hah he used tiny vias
12:59 PM rue_mohr: huh
01:09 PM aandrew: 3x5 for $20 is pretty expensive
01:10 PM aandrew: I want to use the 3018 to route PCBs but it's a mess. I didn't bring it down with me in the car but I'm trying to find a (somewhat) economical way to ship a pallet or two down here. The prices I've been quoted so far are absolutely insane. $1500 for one 500lb pallet, door-to-door, and there'd be customs bullshit to deal with as well
01:14 PM aandrew: I also need to resume my switchable USB hub project. basically take any cheap USB hub that has individual port switches and replace the switches with mosfets, and have "some way" to switch them. Some way probably being a combination of a USB peripheral + wifi or ethernet, since chances are if I'm switching USB power on and off it's possible that the entire USB bus is fucked anyway
01:22 PM aandrew: there are a few "utility" projects I keep slacking off on which would help me considerably... a smarter USB hub, an rpi "power supply concentrator" which I can talk to and will "translate" my commands to the correct SCPI or modbus commands to my bench supplies, and a generic esp8266/32 wifi serial port with full flow control, 232/485 and a few independent switchable relay contacts
01:22 PM aandrew: there's lots of similar stuff online for these but they're all "almost right" but done so oddly that it's more hassle than benefit to try to modify them for my needs than just do my own
01:22 PM aandrew: ... which is probably how there are so many similar things online in the first place.
01:28 PM rue_mohr: what kinda protocol for the switch control?
01:44 PM rue_mohr: I wonder if I can do anything with the i2c eeprom that I put on that first CPLD baord
01:44 PM rue_mohr: er, second, the BGA was the frist
01:44 PM rue_mohr: this is the 3rd, hmmm, I should do something with one of them
07:40 PM aandrew: rue_mohr: probably just a simple web page + rest api, something like http://usbswitch.local/power/1/on, /3/off, 1/cycle etc
07:40 PM aandrew: that would make it compatible with mqtt as well which lets me avoid doing anything pretty
11:03 PM rue_mohr: yea that kinda what I mean, protocol
11:07 PM rue_mohr: wow, twitter likes are rolling in about 1/minute, the bot thing is getting crazy
11:10 PM aandrew: yeah twitter is pretty much useless these days
11:10 PM aandrew: $44B well spent, way to go moron, er I mean Elon
11:28 PM rue_mohr: I think he wants to kill it, I think it costs more to have alive then it would ever make
11:28 PM rue_mohr: but I think he needs 'the people' to kill it, so hes slowly adding salt till everyone is gone