#garfield Logs

Mar 28 2020

12:33 AM rue_mohr: li-ion
12:42 AM rue_mohr: ok, I made a heat deetector for the bathroom tap
12:42 AM rue_mohr: turns on a light when the pipe gets warm
12:46 AM rue_mohr: hmm but I wonder
12:46 AM rue_mohr: its having a bit of trouble with the low temp diff
01:18 AM rue_shop1: ugh, the gain of a TL431 SUCKS
01:28 AM rue_shop1: polprog!! oh you gonna love this!
01:38 AM rue_mohr: I found my chart of transistors as varactors
01:39 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1150607.jpg
05:34 AM rue_mohr: polprog, cant sleep or awake again
05:44 AM polprog: morning rue_mohr
05:44 AM polprog: so youve been using the 4 pin photointerruptor right?
05:49 AM rue_mohr: .. did you see the photos?
05:50 AM rue_mohr: I @'d you...
05:50 AM rue_mohr: :/
05:51 AM rue_mohr: https://twitter.com/RueNahcMohr/status/1243755562006794240
05:51 AM rue_mohr: odd
05:51 AM rue_mohr: no
05:51 AM rue_mohr: sorry, not it
05:51 AM rue_mohr: wtf
05:52 AM rue_mohr: wtf
05:53 AM rue_mohr: dude, a huge chunk of twitter time is missing
05:54 AM rue_mohr: https://twitter.com/RueNahcMohr/status/1243708350719594496
05:54 AM rue_mohr: there is it
05:54 AM rue_mohr: oh It... huh
05:54 AM rue_mohr: strange I have to make sure I dont put an @ at the start of the text
05:57 AM rue_mohr: but do ask questions!!!
05:57 AM rue_mohr: I think I usually ran the output of that circuit into a 74xx14 anyhow
05:58 AM rue_mohr: I can walk you thru reverse engineering the sensor if you want
05:58 AM polprog: i did
05:58 AM polprog: so a 4 pin.. analogue one
05:59 AM rue_mohr: well
05:59 AM polprog: the mention worked btw
05:59 AM polprog: i had your post in my notifications
05:59 AM rue_mohr: good show, it made is dissapear from all my stuff
06:00 AM polprog: All my interruptors are of the 2+3 pin kind
06:00 AM polprog: so as you said, vcc, gnd, Y
06:00 AM polprog: ill check it out, ive got one with wires soldered on
06:00 AM polprog: gimme a sec
06:01 AM rue_mohr: haha, this time I'm about to fall asleep!
06:01 AM rue_mohr: but I'm cooking supper, so you have some time
06:04 AM polprog: haha
06:05 AM rue_mohr: ? :)
06:07 AM rue_mohr: ok, so I have an idea
06:08 AM rue_mohr: you take a signal, like a 40Khz ramp
06:08 AM rue_mohr: and feed it into a schmitt trigger
06:09 AM rue_mohr: this is for measuring stupid tiny voltage differences
06:09 AM rue_mohr: so, you take the ramp, and feed it directly to one trigger, but you offset it by your tiny voltage and feed that to another trigger
06:09 AM rue_mohr: you digitally compare the time difference between the two triggers
06:09 AM polprog: hmm
06:10 AM rue_mohr: ADC
06:10 AM polprog: hmmm.... hct14 based ADC? :P
06:10 AM polprog: i was thinking about that
06:10 AM rue_mohr: well
06:10 AM polprog: i cant get an output from this photointerruptor
06:10 AM rue_mohr: 74hc14 -> 7486 ->7400
06:10 AM polprog: pretty much
06:10 AM polprog: but 30 years too late :D
06:11 AM rue_mohr: trigger -> inversion/buffer (using xor gives you the same time delay) and then compared with an AND
06:11 AM rue_mohr: it will only give you one of the edges, which is all you technically want
06:11 AM rue_mohr: polprog, ok, do you have a sensitive led (like blue) and a 1k resistor?
06:11 AM polprog: i mean, i have the ir led energized, and im looking at the scope output from the Y pin
06:11 AM rue_mohr: oh, 5 pin model or 4?
06:12 AM polprog: 5
06:12 AM polprog: the sharp one here: https://polprog.net/rozne1/ircjunk/cradleservo/photoint_pinout.png
06:13 AM polprog: oh,, i found a clear red led
06:14 AM polprog: there it is, light blue..
06:15 AM rue_mohr: ok
06:15 AM rue_mohr: why do you have to keep injecting light into these
06:15 AM rue_mohr: those digtal ones are failproof
06:15 AM rue_mohr: ok hold on
06:15 AM rue_mohr: polprog, ok, do you have a sensitive led (like blue) and a 1k resistor?
06:15 AM polprog: yesh
06:16 AM polprog: yeah*
06:16 AM rue_mohr: ok
06:16 AM rue_mohr: so, wire them up to a 5V supply to light up the led
06:16 AM rue_mohr: then put the 2 pin emitter terminals in series with them, make sure the led still lights
06:17 AM rue_mohr: ? did that make any sense?
06:17 AM polprog: moment
06:17 AM polprog: ok
06:17 AM rue_mohr: I'm really tired right now and its possible I'm just mashing the keyboard randomly
06:17 AM polprog: so, vcc -> IR LED -> blue led -> 1k ->gnd
06:18 AM rue_mohr: yup
06:18 AM rue_mohr: make sure the blue led lights up!
06:18 AM rue_mohr: (its a sanity check)
06:18 AM polprog: ok
06:18 AM rue_mohr: it look good?
06:19 AM rue_mohr: if thats working, give the detector its gnd and vcc
06:19 AM polprog: yeah, the led light up
06:19 AM polprog: ok
06:19 AM rue_mohr: put a 1k pullup on the Y (Q, whatever) pin, and tell me the voltage, should be V<0.5
06:20 AM polprog: oh, i didnt have a pullup, lol
06:20 AM polprog: ill see if this helps
06:20 AM rue_mohr: :)
06:20 AM polprog: ok.. with nothing in between i have +1v on the Y pin
06:21 AM rue_mohr: huh, not right
06:21 AM rue_mohr: should be WAY lower
06:21 AM polprog: putting stuff inside doesnt change it...
06:21 AM rue_mohr: maybe it needs more emitter but it should
06:21 AM polprog: wait
06:21 AM rue_mohr: are yu SURE the power isn't backwards to the detector
06:21 AM rue_mohr: its a logic device, reverse power would fry it
06:22 AM polprog: detector wasnt getting power. im running vcc to it thru a 1k because othrweise it shorted out my psu at 1.5V (i have 100mA limit set here)
06:22 AM rue_mohr: !
06:22 AM rue_mohr: maybe your power pins are backwards!
06:23 AM polprog: maybe
06:23 AM rue_mohr: that would be what it would do
06:23 AM polprog: ok
06:23 AM rue_mohr: but 100mA is enough to cook it too
06:23 AM polprog: now we have +5v out
06:23 AM polprog: yay
06:23 AM polprog: it werks!
06:23 AM rue_mohr: ? ok
06:23 AM rue_mohr: huh, they usually take 5V in directly
06:23 AM polprog: i have a logic signal output, it drops to 0 when i put something in
06:24 AM rue_mohr: :)
06:24 AM polprog: the power was wrong, i can remove the 1k now
06:24 AM rue_mohr: there is no sensitivity adjust, so, to see thru paper you can only adjust the emitter
06:24 AM rue_mohr: :)
06:25 AM rue_mohr: ok, so whatever you do with that interrupter
06:25 AM rue_mohr: make sure its part of taking over the world
06:25 AM polprog: by autonomous water robots. thats right
06:28 AM polprog: whats for supper
06:28 AM rue_mohr: done
06:28 AM rue_mohr: perogies and a wiener
06:28 AM polprog: approved
06:28 AM rue_mohr: .. and a bit too much salt...
06:28 AM rue_mohr: meh
06:34 AM polprog: lookslike it needs at most 100 ohms to see thru 2 layers of sticker paper
06:35 AM polprog: maybe i could try graph paper and double sided tape to fasten it
06:35 AM polprog: i think graph paper is also a bit more water resistant
06:41 AM polprog: https://polprog.net/rozne1/ircjunk/cradleservo/2mm10mmgrid-v2.svg
06:57 AM rue_mohr: ouch, I dont suggest less than 150 ohms
07:02 AM polprog: yeah, thats why i printed that on semitransparent graph paper
07:11 AM rue_mohr: gngiht
07:11 AM rue_mohr: haha its 5am
07:11 AM polprog: nite!
07:13 AM polprog: funnt, i found a red led that has thepolarity wrong... the 'anvil' is positive
07:23 AM Tom_L: woops
07:27 AM polprog: here's for rue when he wakes up: https://polprog.net/rozne1/ircjunk/cradleservo/graticule.png https://polprog.net/rozne1/ircjunk/cradleservo/photoint_trace.png thats at 1k for the emitter
07:32 AM polprog: https://polprog.net/rozne1/ircjunk/cradleservo/graphpaper.png
07:58 AM polprog: i misprinted the grid as portrait first.. so i have a 1mm potch here
07:58 AM polprog: that seems to be okay with the photointerruptor
07:58 AM polprog: ill have to print some even finer pitches and try
11:59 AM polprog: holy crap
11:59 AM polprog: it works
11:59 AM polprog: ive blown the crap out of one photointerruptor but now it works
11:59 AM polprog: and counts the steps flawlessly
12:19 PM polprog: https://twitter.com/polprogpl/status/1243946929324732416
12:24 PM Tom_L: cool
12:45 PM rue_mohr: polprog, yes, there are some red leds that are backwards
12:46 PM rue_mohr: hah, thats a lot of fine probe work
12:47 PM polprog: where :v
12:47 PM rue_mohr: the photo
12:47 PM rue_mohr: good show
12:47 PM polprog: the video from twitter or the ez-hooks?
12:47 PM rue_mohr: you need to make the speed proportional the the error now, with a trapazoidal velocity profile
12:48 PM rue_mohr: your links you left
12:48 PM polprog: ah
12:48 PM rue_mohr: https://polprog.net/rozne1/ircjunk/cradleservo/graticule.png
12:48 PM rue_mohr: that one
12:48 PM polprog: oh yeah. i like these hooks
12:48 PM rue_mohr: yep
12:50 PM polprog: i need to retry what's the max speed it can do now
12:50 PM rue_mohr: for a mechanical thing, it should be pretty high
12:50 PM polprog: i think delays smaller than something make the belt slip
12:51 PM rue_mohr: yup, you need to cap the velocity
12:51 PM rue_mohr: even if its a dc motor
12:51 PM polprog: but im worried since, iirc, the delay between steps is not 6000 nop loops... and i think it was slipping at 4000-ish
12:52 PM rue_mohr: it looks a long way off from having issues unless you dont ahve nearly enough drive voltage to the stepper
01:00 PM polprog: yeah i think i made an oops in my driver
01:00 PM polprog: i need to cut one wire and then ill be able to run the stepper off, say, 12V
01:02 PM polprog: but i wont be touching that today.. heatsink is bodning
01:02 PM polprog: thats 24h wait time
01:16 PM rue_mohr: https://m.media-amazon.com/images/S/aplus-media/sc/f9c1e10e-0afd-4b37-a5f7-1148c5578aa3.__CR0,0,300,300_PT0_SX300_V1___.jpg
01:16 PM rue_mohr: tom!!!
01:16 PM rue_mohr: THATS that line I'm after!
01:16 PM rue_mohr: I think thats the size too
01:17 PM rue_mohr: my sinuses are all stuffed up, am I gonna die?
02:19 PM Tom_L: gas syphon
02:19 PM Tom_L: we're all gonna die
02:19 PM Tom_L: sooner or later
02:39 PM rue_mohr: I'm not arguing that, I just need to hold off on it for about 9000 years
03:56 PM polprog: ive had runny nose for 3 or 4 years when i was 7, and look what happened to me now
04:14 PM rue_mohr: :)
10:26 PM Tom_L: never used to have allergies
11:09 PM rue_mohr: https://makezine.com/2020/03/27/make-these-projects-to-fight-covid-19-right-now/
11:09 PM rue_mohr: thats collected