#garfield Logs

Nov 27 2024

01:58 AM VanUnamed_ is now known as VanUnamed
02:26 AM polprog: i updated some errors in the redox page
04:54 AM rue_mohr: redox?
04:54 AM rue_mohr: oh
04:16 PM polprog: that group buy company has something screwed up with their email
04:16 PM polprog: second time they dont get my reply with the gerbers
04:16 PM rue_mohr: 192.168.8.189
04:17 PM rue_mohr: osh?
04:17 PM polprog: i emailed the bossman of it, its a small business, he should send me the proforma invoice for the 8051
04:17 PM polprog: no, oshpark shipping to here is killer
04:17 PM rue_mohr: k
04:18 PM polprog: this is some small "startup" that has a newsletter/mailing list and pools up orders to some chinese manufacturer
04:18 PM rue_mohr: so, are your 8051 boards happening?
04:18 PM polprog: perhaps even JLCPCB
04:18 PM polprog: yes, i thought they would be earlier but i just sent the files today
04:18 PM rue_mohr: why not go to jlcpcb direct?
04:18 PM polprog: i wanted to save a few $ on group shipping
04:18 PM rue_mohr: huh
04:18 PM polprog: but i think if i have to ask everytime if they got the files ill just order from JCL directly
04:19 PM rue_mohr: I suppose because I use ground shipping its not an issue
04:19 PM polprog: using that group buy is neither faster nor better that ordering directly, the only upside is the postage costs spreads to all boyers
04:19 PM polprog: but i cant change the soldermask color or thickness or other stuff
04:19 PM polprog: JLC really kills it with their options
04:20 PM polprog: yeha i use ground shipping too unless i need the boards for yesterday
04:20 PM polprog: $8 for postage from China of all places is very good price
04:20 PM rue_mohr: jlc shipping is like $2 for me
04:25 PM polprog: hm i think i dont choose the cheapest option
04:25 PM polprog: the $8 is the best value for money for me
04:25 PM rue_mohr: hmm, I cant remmeber what they call it
04:25 PM rue_mohr: direct global shipping or something
04:27 PM polprog: I take the one called "europacket"
04:27 PM rue_mohr: ok
04:27 PM polprog: i wonder when my DAC pcb comes
04:28 PM rue_mohr: oh? what did you do?
04:32 PM polprog: i made a 2-dac breakout board, arduino compatible for MCP4922
04:33 PM rue_mohr: ah!
04:33 PM polprog: 12-bit, i put some LM4040 2.048V references as VREF
04:33 PM polprog: that will be the D/A part of my yig controller
04:33 PM rue_mohr: huh, not 2.5V?
04:33 PM polprog: 2048 scales nicely with dac step
04:33 PM rue_mohr: oh right
04:33 PM polprog: i need to come up with some clever way to make a 0-10V output stage having a single ended 5 or 12V supply
04:34 PM polprog: and it needs to be VERY quiet
04:34 PM rue_mohr: hmm
04:34 PM polprog: as in, i want no AC
04:34 PM polprog: so minimal use of switchers
04:34 PM polprog: though if i decoupled it allright, i could pull off a 12V to minus-something converter
04:35 PM polprog: https://ibb.co/5B3cdXQ
04:35 PM polprog: this is the board
04:40 PM rue_mohr: ooo a doodle area!
04:41 PM polprog: :D
04:41 PM polprog: kicad adding the bitmap to footprint converter is the best thing since sliced bread
04:41 PM polprog: i dont have to hack around scripts to add silly drawings to my PCBs
04:42 PM polprog: so this dingus will plug onto the arduino header onthe ch32v207
04:42 PM rue_mohr: ok
04:45 PM polprog: i will be testing the resolution of the photomask
04:45 PM polprog: the initial etch went fast, but it was overetched. my ferric was too strong
04:46 PM rue_mohr: ooo, didn't really think to use the copper layer for text and stuff
04:46 PM rue_mohr: it doesn't take long to etch
04:46 PM rue_mohr: using ferric
04:46 PM rue_mohr: did you warm it up,
04:46 PM rue_mohr: I think reccomended is like 40-50c
04:46 PM polprog: maybe im old fashioned (sic) but there was one board house I was using when i was starting PC design, they had a requirement to put some text on each layer
04:46 PM polprog: Yes, i had it at 50-ish
04:47 PM rue_mohr: huh
04:47 PM rue_mohr: I recall like 5 miutes of less
04:48 PM polprog: that sounds right
04:48 PM polprog: https://0x0.st/XRBL.jpg
04:49 PM polprog: im not sure if this is due to underexposed photomask, or too strong ferric
04:49 PM polprog: the edge is OK
04:49 PM rue_mohr: probably bad mask
04:49 PM polprog: but the overetch in the middle is bad
04:49 PM rue_mohr: yea solder wont take to that well
04:51 PM polprog: for this project i dont need solder
04:51 PM polprog: https://hackaday.io/project/19898-make-your-own-pcb-etchant/details
04:51 PM polprog: man, he's making his own FeCl3 in muriatic acid
04:52 PM polprog: i got FeCl3 hexahydrate from the distributor, it came as large lumps in a white jar
04:52 PM polprog: the hexahydrate lumps look exactly like curry chicken
04:53 PM polprog: i need to etch some structures for optics, i might tin them chemically for longevity
04:53 PM polprog: i found an unopened pack of chemical tinning bath agent
04:54 PM rue_mohr: the tin stuff is nasty, nice finish tho
04:54 PM rue_mohr: what are you masking with?
04:58 PM polprog: thats why i didnt use it back then, but i got some better chem equipment now
04:58 PM polprog: im experimenting with Positiv 20 UV curable mask
04:58 PM polprog: and im using my laserjet to print the transparencies on slide foil
04:59 PM polprog: the print quality seems OK down to .7 - .5 mm on the transparency, and i will be testing the resolution of the photomask in the coming days
05:01 PM rue_mohr: hmm
05:01 PM rue_mohr: just 1 photomask layer?
05:01 PM polprog: yes
05:01 PM rue_mohr: off to work
05:02 PM polprog: it's funny because you spray it, then bake at 75 deg C, then expose and develop in hydroxide
05:02 PM polprog: have a nice day rue!
05:02 PM polprog: i think ill be off to bed soon
05:02 PM polprog: ill keep you posted