#garfield Logs

Mar 21 2020

01:14 AM rue_mohr: Tom_L,
01:20 AM rue_mohr: do you think there is a way to set up a global wire
01:20 AM rue_mohr: I want one for clocking all my modules
01:20 AM rue_mohr: without having to specify it as an input for each module
01:20 AM rue_mohr: https://www.edaboard.com/showthread.php?174172-How-to-define-global-variable-in-verilog
01:20 AM rue_mohr: I wonder, I think I have to go back to flashing leds for a bit
04:56 AM polprog: rue_mohr: ive measured the trasnsitor, its either OL or 2Mohm
04:56 AM polprog: its connected the way it showed 2Mohm
04:56 AM polprog: also, dont worry. I am chaotic as well
04:57 AM polprog: thanks for being my shoutbox yesterday. I actually got an email back with probably the grade but i done wanna read it before breakfast
05:30 AM polprog: nope.. it's definitely the right way in
05:31 AM polprog: the current issue is that if i have my bench lamp on it just goes crazy, showing all time high
05:32 AM polprog: when it's off completely it shows all time low
05:32 AM polprog: so i'd have to put something to cash shadow over the thing
05:32 AM polprog: and fix the VCC noise
05:33 AM polprog: i wonder if i could run it off 9/12V and use a 7805 for the stm32
05:33 AM polprog: or should i try throwing more caps at it
10:40 AM rue_bed: make that 22k resistor in my circuit smaller, and it'll reduce the sensitivity
10:50 AM rue_bed: polprog, actually, it occurs to me, that the fastest circuits should be among those optocoupler ones I as playing with
10:50 AM rue_bed: I had the most awesome electronic lab book in my dream
10:50 AM rue_bed: nothing tech couldn't do, but nobodys done it
10:51 AM rue_bed: basically a tablet, but with great software
11:12 AM polprog: hmm
11:13 AM polprog: if someone made an A4 sized tablet with proper stylus support
11:14 AM polprog: you could just use it as a PDF notepad.
11:14 AM polprog: the issue is that with the circuit i posted, even though it's a darlinton pair, i need a 1M resistor to get a signal that crosses 2v5 at some point
11:15 AM polprog: so this means the current, even thru the BC547 is in the order of microamps
11:15 AM polprog: so loading the phototransistor more wont help
11:15 AM polprog: i tried your circuit in some configurations
11:17 AM rue_bed: in my dream I was able to take pictures and paste them into the pages, then erase and modify them
11:17 AM polprog: hmm
11:17 AM rue_bed: as well as zooming and sylus writing
11:18 AM polprog: the pencil and a file of a4 sheets is pretty good for me
11:18 AM rue_bed: you need to reduce your gain of the darlington, thats what the 22k is for
11:18 AM polprog: hmm
11:18 AM polprog: i havent thought about it like that
11:18 AM polprog: i should continue reading taoe
11:18 AM rue_bed: you adjust the 22k and it'll change the sensitivity
11:18 AM polprog: ill reduce the gain later.. dinner time
11:18 AM rue_bed: but its not darlinton
11:19 AM polprog: also, replaced a battery in the scope
11:19 AM polprog: dinner, bbl
11:19 AM rue_bed: the phototransistor cant produce enough current to damage anthing
11:19 AM rue_bed: its been my leading opto-interrupter circuit
11:19 AM rue_bed: for a long time
11:20 AM rue_bed: and npn is fine
11:21 AM rue_bed: one thing I realized that I'v never tried employing in circuits to combat the slowdown due to capacitance, is inductors
12:16 PM Tom_L: rue_bed, i dunno
01:15 PM rue_mohr: well, my energy has been completely zapped out latley
01:15 PM rue_mohr: record amounts of sleep
01:15 PM rue_mohr: gonna go stand outside and try to motivate myself
01:15 PM rue_mohr: it would be a good idea to plant my potatoes
01:25 PM Tom_L: off work?
01:37 PM polprog: i managed to get something that gives me sensible output
01:50 PM polprog: https://polprog.net/rozne1/ircjunk/cradleservo/frontend4.png
01:51 PM polprog: https://polprog.net/rozne1/ircjunk/cradleservo/PRINT_12.png
01:52 PM polprog: the output signal is good in its amplitude
01:52 PM polprog: if i add a small shadowmaker it will be good to go into a scmitt trigger
01:52 PM polprog: sch*
02:20 PM polprog: awesome
02:20 PM polprog: its moving precisely now
03:29 PM rue_mohr: hmm
03:29 PM rue_mohr: I still say you need the pulldown
03:30 PM polprog: the pulldown makes it not work ;/
03:50 PM rue_mohr: use a higher resistance, like 100k
03:50 PM rue_mohr: you have to adjust that value for the ambient light and the detector gian
03:51 PM rue_mohr: if you add _something_ it will speed up the rise time
03:51 PM rue_mohr: if you have a 1M pot, go thru a range
03:54 PM polprog: hmm
03:54 PM polprog: speed up rise time you say
03:54 PM polprog: ill try a 1M resistor and divide it down with some 100ks
03:54 PM rue_mohr: dial it from about 1M down to about 50k, you will find a sweet spot
04:17 PM polprog: stepper driver works but the steps seem to be not in order again
04:29 PM rue_shop2: whats the stepper driver?
04:29 PM polprog: l293d
04:29 PM polprog: im exmining control wfms
04:29 PM polprog: it works if i drive it with my step funcion byt mu go_pos() function makes it move erratically
04:33 PM polprog: they seem in order
04:35 PM rue_mohr: hmm
04:38 PM polprog: they are in order
04:39 PM polprog: and in the test code (step right forever) it slowly goes right but sometiems will twitch back
04:41 PM rue_mohr: sounds like your coils are out of order
04:41 PM polprog: might be
04:41 PM rue_mohr: there is a seqence where that happens
04:41 PM rue_mohr: your running them unipolar?
04:41 PM polprog: there are two coils, 1-3 and 2-4
04:42 PM polprog: there is no common wire
04:42 PM rue_mohr: ah bipolar
04:42 PM rue_mohr: thats strange then
04:42 PM rue_mohr: bipolar cant be wrong
04:42 PM rue_mohr: 4 wire motor?
04:42 PM polprog: thats why i needed the 239. if this was unipolar id just whack an uln here
04:45 PM polprog: hmm. halfstepping seems to have helped?
04:45 PM rue_mohr: maybe your stepping it too fast and its hitting resonance
04:46 PM polprog: im stepping it slower than usual
04:46 PM rue_mohr: http://homepage.divms.uiowa.edu/~jones/step/
04:47 PM rue_mohr: http://homepage.divms.uiowa.edu/~jones/step/physics.html <-- figure 2.9
04:48 PM polprog: HA
04:48 PM polprog: i have it
04:48 PM polprog: i had a delay in the code
04:48 PM polprog: that made the stepper controller do 0000
04:48 PM rue_mohr: ok
04:48 PM polprog: now with halfstepping this is smooth as heck
04:57 PM polprog: hmm
04:57 PM polprog: its twitchy sometimes
04:59 PM polprog: huh
04:59 PM polprog: it must be bad connections
05:18 PM Tom_L: or noise from the stepper
05:34 PM polprog: seems to be the resonance
05:34 PM polprog: i changed the speed and it works without a hitch now
05:34 PM polprog: it even goes back to zero correctly
05:48 PM rue_shop1: polprog,
05:48 PM rue_shop1: the ground connection between your avr and your driver
05:48 PM rue_shop1: check it
05:48 PM polprog: i ran one actually and it improved...
05:48 PM polprog: so its good now
05:55 PM rue_shop1: :/
05:55 PM rue_shop1: that took me too long to work out
05:55 PM rue_shop1: it should have clicked when you said 0000
05:56 PM polprog: no, the zeros were due to a code bug
06:29 PM polprog: i cant get it any sensible to work with any resistance on the base
06:30 PM polprog: nighters
09:14 PM rue_mohr: odd
09:25 PM Tom_L: rue_mohr, how you feelin?
09:25 PM rue_mohr: I'v had something for a while
09:26 PM rue_mohr: long before the virus was going around
09:26 PM rue_mohr: got no energy, its annoying
09:26 PM Tom_L: yeah now if i even sneeze somebody things it's virus
09:26 PM rue_mohr: rough throat, you should see the polen wafting off the trees here!
09:26 PM rue_mohr: yea
09:27 PM Tom_L: when we were in savannah, in the morning there was a yellow film on the cars
09:27 PM rue_mohr: clouds of polen
09:27 PM rue_mohr: yea, thats happening here now
09:27 PM Tom_L: it's real bad down there
09:28 PM rue_mohr: I was outside today when a branch fell off a tree and shook a cloud of it free, watched it drift over the house
09:28 PM rue_mohr: :S
09:28 PM Tom_L: what kind of trees?
09:28 PM Tom_L: pine?
09:28 PM rue_mohr: alder
09:29 PM rue_mohr: there like weeds around here
09:29 PM rue_mohr: I grew a bunch in the back yard to act as temporary fill
09:29 PM Tom_L: hmm
09:29 PM rue_mohr: they are about 8" dia now
09:29 PM rue_mohr: and starting to drop lots of 3/4" branches
09:30 PM Tom_L: the elm by my back door now is ~10' circumference
09:30 PM rue_mohr: cool
09:30 PM rue_mohr: a real tree
09:30 PM Tom_L: it was there when i moved in in 79
09:30 PM Tom_L: and a fair size then
09:31 PM rue_mohr: so, I went to a lot of effort to make a transformer, and blew the order of magnitude for its inductance
09:31 PM rue_mohr: 100uH instead of 1mH
09:31 PM rue_mohr: so, wrong core
09:32 PM rue_mohr: tried, remembered the numbers wrong
09:32 PM rue_mohr: its making me want to try again
09:38 PM rue_shop1: intesting, turns out the coiles I liked are 10mH
09:39 PM Tom_L: i'm at a loss when it comes to inductance and coils
09:41 PM rue_shop1: V=L*I/t
09:50 PM rue_mohr: an inductor is a capacitor for current
09:50 PM rue_mohr: when you apply voltage, the current slowly ramps up
09:51 PM rue_mohr: just like with a capacitor when you apply current, the voltage slowly ramps up
09:51 PM rue_mohr: the ramp being determined by the size of the thing
09:51 PM rue_mohr: small cap, fast ramp
09:51 PM rue_mohr: eh?
09:56 PM Tom_L: hmm
09:57 PM rue_mohr: in the case of a secondary winding, the voltage will track the drive winding on a per-turn basis
09:59 PM Tom_L: what determines the current capacity? the wire gauge?
09:59 PM rue_mohr: also the maternal the core is made out of
09:59 PM rue_mohr: materials can only take so much magnetizm
10:00 PM rue_mohr: then they 'saturate'
10:00 PM rue_mohr: its like the film breaking thru on a capacitor with too much voltage
10:01 PM rue_mohr: in the same way that a capcitor will create whatever current it needs during a short to try to maintain voltage, an inductor will create whatever voltage it can to maintain current during an open
10:04 PM rue_mohr: the 'capacity' of the inductor tho, in the mH sense, is a combination of the number of turns and the core material
10:04 PM rue_mohr: the maximum current being a wire guage and mateial combination
10:04 PM rue_mohr: damnit, I'm just tired
10:05 PM rue_mohr: constantly tired
10:07 PM Tom_L: seems like alot more to consider with inductors
10:09 PM rue_mohr: na
10:09 PM rue_mohr: a bit more if your making them
10:09 PM rue_mohr: when you just buy them, they ahve a uH and current rating
11:46 PM rue_mohr: zhanx, ?
11:46 PM zhanx: “If freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter.”
11:48 PM rue_mohr: excellent, your alive
11:49 PM rue_mohr: I went looking on the internet to buy "the encyclopedia of electronic circuits" volumes 1 & 2, accidently downloaded 4 & 5 and then found 2
11:49 PM rue_mohr: but bought 1 and 2
11:49 PM rue_mohr: amazo
11:49 PM rue_mohr: n
11:51 PM rue_mohr: seeing as my brain is being otherwise useless, I'm paging thru the pdfs