#garfield Logs

Jul 07 2021

01:21 PM polprog: yeah
01:28 PM polprog: i got some trimmers though
01:28 PM polprog: pf range
07:31 PM rue_mohr: what am I supposed to do?
07:31 PM Tom_L: what did you forget to do?
07:32 PM rue_mohr: I told someone I would chack avr interrupt reates
07:32 PM rue_mohr: they cant get more tha 400Hz
07:33 PM Tom_L: that seems kinda slow
07:41 PM rue_mohr: it is
07:41 PM rue_mohr: I'll see what i can get one to do
07:41 PM Tom_L: would it also depend on the interrupt priority?
07:44 PM rue_mohr: not if nothing else is going on
07:54 PM aandrew: how fast can the cpu save context, look up the vector and jump to it and then get back to normal? that could be limiting things on (limited) CPUs
07:54 PM aandrew: way back in the stone age I'd designed a PIC16C74A (then 77, then F877) three phase motor starter and it never got more than about 190 instructions between interrupts
07:56 PM aandrew: that was PIC though, and 8MHz
07:56 PM Tom_L: was that back when wheels were still square?
08:01 PM aandrew: indeed, back when the chip vendors thought they should double-dip by charging you for the compiler too, which is why I wrote it in asm
08:02 PM rue_mohr: did you here how I did a sine wave gen on an avr?
08:02 PM rue_mohr: I can get up to about 20khz irrc
08:02 PM aandrew: no, but I saw the ROM one you did not too long ago
08:02 PM aandrew: unless I'm mixing up your projects
08:02 PM aandrew: you're incredibly prolific
08:03 PM rue_mohr: I locked the avr into a loop loading values and pushing them to a port (8 bit DAC)
08:03 PM rue_mohr: to change the freq, I varied the avrs clock
08:03 PM aandrew: heh
08:03 PM rue_mohr: so it only took 2 cycles/sample
08:03 PM rue_mohr: I used the stall at the peak of the sinewave to do the jump, because the output didn't need an update
08:05 PM aandrew: that's a neat trick
08:05 PM rue_mohr: so 16MHz/512
08:06 PM rue_mohr: (256 samples)
08:06 PM rue_mohr: 31kHz
08:07 PM rue_mohr: I guess the best trick would be to get the watchdog to reset the loop for you just at the right time
08:23 PM rue_shop7: I get 530kHz
08:26 PM rue_shop7: 11 instructions
08:31 PM rue_shop7: but the crystal is quiet
08:42 PM rue_shop7: nup, even @16Mhz for sure, 540kHz
08:55 PM aandrew: hm, I figured out why I don't like my little ksger soldering iron
08:55 PM aandrew: the ones you can get for like $30 and use T12 tips
08:55 PM rue_mohr: ok
08:55 PM rue_mohr: why
08:55 PM aandrew: it's the handle -- the grip is too far away from the tip. my ancient metcal grip is 35mm from the tip; the ksger is almost 75mm
08:55 PM aandrew: I did find a ksger-compatible tip that was 42mm away, ordered one to see if that helps
08:56 PM aandrew: I wanted a cheap, small, "good enough" soldering iron for work away from home, the ksger is decent but could never figure out why I didn't like using it
08:56 PM aandrew: it dawned on me earlier this week
08:59 PM aandrew: I wonder if I can make an "extender" that slides on to the tip and gets me down to 30-35mm. I could make a stainless steel "collar" that was 15mm long, maybe 10-15mm dia, with a 5mm dia hole in the middle and then take a wood dowel that was about 20-25mm dia with a 10-15mm dia hole in the middle to make a grip extension
08:59 PM aandrew: the handle I have now won't work for that because the tip is secured with a little tube and a threaded collar which would get in the way
09:00 PM aandrew: but the new handle I ordered would work with that
09:01 PM aandrew: https://www.ebay.com/itm/KSGER-FX9501-Handle-T12-Soldering-Iron-ABS-DIY-Pen-For-STM32-OLED-Soldering/124185442097
09:01 PM aandrew: that one, but from ali
09:02 PM aandrew: in other news
09:02 PM aandrew: https://www.eevblog.com/forum/programming/constructing-short-c-strings-in-limited-or-constrained-situations/?topicseen
09:02 PM aandrew: I think it's kind of amusing that they're talking about not needing to use divide for printing numbers on amd64 arch
09:04 PM aandrew: lots of good info in that thread, nothing really *new*, but fun
09:20 PM rue_mohr: k
09:21 PM rue_mohr: did you see my code for printing decimal numbers?
09:22 PM rue_mohr: "my" I modified it from somewhere
10:01 PM aandrew: quite possibly
10:05 PM rue_mohr: hah, that link to the tip?
10:05 PM rue_mohr: I'v never seen the ad blocker get to 25 before
10:10 PM aandrew: hahaha
10:11 PM aandrew: https://www.aliexpress.com/item/4000116326529.html is what I actually ordered
10:11 PM aandrew: ublock origin shows 30 there
10:12 PM aandrew: and a youtube video easily hits several hundred
10:46 PM rue_mohr: :)
10:47 PM rue_mohr: what power supply does it need?
10:59 PM aandrew: I'm not 100% sure, I haven't dove into it much. my base unit is a stupid little KSGER thing from amazon
11:04 PM rue_shop7: hmm
11:04 PM aandrew: 5 pin interface
11:04 PM rue_shop7: I got a hakko 936 controller, and added a case and transformer
11:04 PM aandrew: I'm sure it's out there, it's been cloned a million times over
11:05 PM rue_shop7: yea, I had to get a new controller, its a hakd 636
11:05 PM rue_shop7: there was a controller chip that went, the whole new controller was cheaper than the chip
11:07 PM aandrew: so far I've spent the last 2 hours talking to various chinese vendors trying to get information the sony IMX258 image sensor. I can buy them but I can't get a proper datasheet
11:07 PM aandrew: funny part is I'm not even lying to them about quantities
11:08 PM aandrew: can't deal with sony directly because for mobile sensors they want 1MM/y volume or they simply won't talk to you. their industrial sensors all have pixel pitches too high, I'm looking for 1.1um or smaller
11:09 PM rue_shop7: hmm
11:10 PM rue_shop7: whats the 'fine' for canceling a run with sony?
11:10 PM aandrew: no idea but Im pretty sure that if they haven't heard of you they know you won't hit 1MM/yr
11:11 PM rue_shop7: does it have to be sony?
11:11 PM aandrew: rue_shop7: speaking of adblockers: https://ibb.co/BKCJC0h
11:12 PM aandrew: rue_shop7: well it's tricky finding a good low light quality image sensor in the 8-15MP range with pixel sizes where I need 'em
11:12 PM rue_shop7: hmm
11:13 PM aandrew: sony's sensors are some of the best for low light
11:13 PM aandrew: and I'll be using a tiny TEC to cool it down to just above the dew point to minimize noise
11:14 PM rue_shop7: can you find a product to buy and scavenge them from?
11:14 PM aandrew: was looking at that too for prototyping
11:14 PM rue_shop7: maybe someone makes a minimal carrier board
11:14 PM rue_shop7: no a whole product
11:15 PM aandrew: well all these vendors are happy to make something for me so that's not the issue
11:15 PM rue_shop7: its the new thing with the way the economy is piling up over itself
11:15 PM rue_shop7: but they cant get you the sensor
11:16 PM aandrew: oh they can get me the sensor just fine
11:16 PM aandrew: just the datasheet is troublesome
11:16 PM aandrew: and really I don't need it, I just want it becuase I plan on tweaking things a bit
11:16 PM rue_shop7: dont call it a datashet
11:16 PM rue_shop7: what did those lcd documents call it
11:17 PM aandrew: and MOST of these fancy sensors have multiple bugfixes you apply by sending blobs over I2C to patch the ROM image in RAM
11:17 PM rue_shop7: submission proposal or something
11:17 PM aandrew: hm
11:18 PM rue_shop7: bascially you write a spec for what you want and they come back with proposals
11:18 PM rue_shop7: just, make your spec quite specific to the sensor you want
11:18 PM rue_shop7: the engineers do that anyhow
11:19 PM rue_shop7: "...and must say 'SONY' on the front"
11:19 PM rue_shop7: I hate that
11:19 PM aandrew: you sound like an alibaba expert
11:21 PM rue_shop7: no
11:21 PM rue_shop7: I'm the pro at turning thing upside down when they wont pry out from the front
11:23 PM rue_shop7: while cleaning the deck I found a pile of laptops that I dont think I'v even evaluated
11:24 PM aandrew: heh
11:25 PM aandrew: you seem to be trying hard to avoid becoming a hoarder :-)
11:26 PM rue_mohr: definitly
11:26 PM rue_mohr: I have 10 laser printers on the deck
11:26 PM rue_mohr: one of them may be basically new
11:27 PM aandrew: I'm trying to remmeber your place. isn't the deck your wraparound porch?
11:27 PM rue_mohr: no, just half the house on the side
11:27 PM rue_mohr: 300 square feet
11:28 PM rue_mohr: I'v designed a 3d printed clip that snaps into 1" panduit raceway cover
11:28 PM rue_mohr: for mounting modules
11:30 PM aandrew: right, but isn't it more or less open to the elements?
11:30 PM rue_mohr: no, its covered
11:30 PM rue_mohr: no sides
11:32 PM aandrew: right that's what I meant. I woudl have expected any electronics out there would be more or less toast in a matter of weeks
11:33 PM rue_mohr: nope, its ok
11:33 PM aandrew: nice, obv you know better than me about your own place
11:39 PM rue_mohr: the problem is, there are 10 laser printers on my deck
11:39 PM rue_mohr: and two large inverters, 5kw I think
11:40 PM rue_mohr: and 10 nortel POE switches
11:41 PM rue_mohr: and a kitchen sink
11:41 PM rue_mohr: and a network rack
11:41 PM rue_mohr: 6 monitors
11:42 PM rue_mohr: about 10 ups'
11:42 PM rue_mohr: an engine
11:42 PM rue_mohr: a box of wire, and a box of pipes
11:43 PM rue_mohr: a box of toner cartridges
11:43 PM rue_mohr: a box of printer fusors
11:44 PM rue_mohr: a roll of carpet
11:47 PM aandrew: heh I have a pile of nortel switches too
11:47 PM rue_mohr: did you know about the mid-sized cplds?
11:48 PM rue_mohr: I think they handle the low speed comms behind the main switch chips
11:49 PM aandrew: I haven't done much with CPLDs
11:50 PM rue_mohr: their just fpgas without the startup delay
11:52 PM rue_shop7: there is another printer in the middle of the shop floor
11:52 PM rue_shop7: laser