#garfield Logs
Dec 03 2020
#garfield Calendar
12:25 AM rue_mohr: I wonder if an hdmi stream has to be continious
12:49 AM rue_mohr: "not your fathers arduino"
12:49 AM rue_mohr: I....
12:49 AM rue_mohr: seriously? are we that far along now?
01:15 AM polprog: hahaha
08:21 AM aandrew: my dad's arduino was an 8085 trainer with a hexadcimal keypad and I think a 6-digit 7-seg display that he had to build
08:45 AM rue_mohr: mmmmmm :)
08:45 AM aandrew: yeah that was my first exposure to embedded
08:45 AM rue_mohr: i8080
08:45 AM aandrew: he'd done a semester in college and I guess it wasn't for him, I found it buried in junk and pulled it out and kind of took off
08:46 AM rue_mohr: its almost amazing that the PC market went 8086
08:46 AM aandrew: I remember looking up opcodes, computing jumps, writing it all down on paper and keying all that shit in manually
08:46 AM aandrew: it was intoxicating
08:46 AM rue_mohr: yep
08:46 AM rue_mohr: I spent a summer on it boostrapping my own monitor for the z80 laptop I did
08:47 AM aandrew: almost every embedded/electronics person I've run across in my career that I've had a real connection with has similar experiences / found similar experiences when they discovered it
08:47 AM aandrew: the guys who are competent but not passionate never made much of an impression with me professionally
08:47 AM aandrew: oh man
08:47 AM rue_mohr: did i ask if you play guitar?
08:48 AM aandrew: in grade 9 I took grade 11 electronics. the teacher had an entire LOFT full of TRS80 Model III cabinets in various states of function (the old computer lab for the school I guess)
08:48 AM rue_mohr: heh
08:49 AM aandrew: he let me do whatever so I combined pieces and made a fully decked out TRS80 out of it and took it home
08:49 AM aandrew: it was so... different from the x86 and C64 stuff I'd worked with before
08:49 AM aandrew: Froelich wrote a book about replacing the basic ROM with a new OS he'd designed (and the book was all about how he went about it including the listings to flash your own)
08:49 AM aandrew: very fun stuff, I remember the SMELL of that computer once it warmed up
08:50 AM aandrew: I don't think you did ask me if I played; I can play some rhythm but no lead
08:50 AM aandrew: haven't touched a guitar in probably 5y now, sadly
09:03 AM rue_mohr: yea funny thing tho
09:03 AM rue_mohr: its scarce to find a programmer who hasn't played guitar at some time
09:09 AM aandrew: interesting
09:09 AM polprog: ive played maybe once...
09:10 AM polprog: classes over for today
09:10 AM polprog: now just the mech homework left
09:11 AM polprog: how are you all?
09:22 AM aandrew: my finger joints all feel funny today
09:23 AM aandrew: not sore, but have a sensation that I can't ignore
09:23 AM aandrew: I was out in the cold yesterday putting up some christmas stuff though, could just be that
09:26 AM polprog: just when the cold weather was getting stronger this week i kept forgetting my gloves
09:51 AM rue_mohr: http://www.learningaboutelectronics.com/Articles/Triangle-wave-generator-circuit-with-an-LM741-op-amp.php
09:51 AM rue_mohr: couldn't get this one to work, but I really really dont think its a fake
10:00 AM aandrew: yeah it's kind of shitty: https://www.circuitlab.com/circuit/9n48eh5r537k/trianglegen/
10:06 AM aandrew: changing R3 (the one in series with the cap) up to 4.7k helps a lot
10:06 AM aandrew: much below that though it starts clipping badly
10:09 AM aandrew: 4.7k and 4.7n actually looks really nice
10:10 AM aandrew: it also takes about 1msec to start up
12:45 PM rue_mohr: ...
12:45 PM rue_mohr: heh
12:46 PM rue_mohr: huh
12:48 PM rue_mohr: I should set up some calibrated caps
12:50 PM rue_mohr: haha
12:50 PM rue_mohr: that lm741 has a bw of 1.5Mhz?
01:03 PM aandrew: I normally hate spice but circuitlab is one of those cloud (ugh) spice (ugh) services that I actually have paid for for the last 5y or so. very handy for little things and the ability to quickly share is also very helpful
01:03 PM aandrew: it also integrates nicely with electronics.stackexchange.com too
02:21 PM polprog: so we had opamp calculations today
02:22 PM polprog: ill have to be able to do that in 20 minutes to pass that bullshit in two weeks
03:09 PM rue_mohr: Zf/Zi
04:07 PM polprog: to some extent
04:08 PM polprog: but you have to manually plot the transmittance graph
04:08 PM polprog: Uout/Uin
04:08 PM polprog: not only that but i have to write out the transformations
04:08 PM polprog: which is pretty much 2 a4 pages
04:09 PM polprog: writing the shit takes about 15 minutes. and you have to scan and send that in
05:00 PM rue_mohr: huh
05:07 PM polprog: yeah
05:07 PM polprog: it's a mes
05:07 PM polprog: mess*
05:07 PM polprog: doesnt really have anything to do with actual electronics
05:53 PM aandrew: it sounds like the goal of the course is to teach you what to ignore/get zero on to maximize the mark
05:53 PM aandrew: oh, my 0.91" OLEDs arrived today, along with my coil forms
05:53 PM aandrew: the shipping from china is really fast lately
06:02 PM aandrew: https://www.aliexpress.com/snapshot/0.html <-- coil forms
06:06 PM aandrew: [X] 5x 0.91" OLED
06:06 PM aandrew: [ ] GY-SGP30 gas sensor
06:06 PM aandrew: [ ] 5-50mm telephoto 12mm lens
06:06 PM aandrew: [ ] 6-22mm telephoto 12mm lens
06:06 PM aandrew: [ ] 10x 2.1mm DC plug
06:06 PM aandrew: [ ] 4x 9pin usbc magjack
06:06 PM aandrew: [ ] 20x dual terminal block
06:06 PM aandrew: [X] 2x s167 drone parts kit w/ motors
06:06 PM aandrew: [X] 2x s167 drone parts kit no motors
06:07 PM aandrew: [X] 50x EE16 transformer core/forms
06:07 PM aandrew: [ ] 100x banana jack mounting posts
06:07 PM aandrew: [X] bootlace ferrules
06:07 PM aandrew: [X] 2x z axis leadscrew mount
06:07 PM aandrew: [X] 2x frsky d8 pwm rx
06:07 PM aandrew: ugh
06:07 PM aandrew: sorry
06:07 PM aandrew: that was not supposed to go here, sorry for the flood
06:07 PM aandrew: that's my current "what I'm waiting for" list though :-/
06:21 PM polprog: i dont know what the goal of the course is
06:21 PM polprog: today he said "Im not going to show you all of the stuff that is necesary"
06:21 PM polprog: (it's a lecture)
06:22 PM Tom_L: or 1/2 a lecture from the sounds of it
06:22 PM polprog: pretty much
06:22 PM polprog: im sure if you don't know half the stuff already then you are pretty lost
06:22 PM polprog: friends say they dont even know what to ask about
06:23 PM polprog: its a shitshow...
06:23 PM Tom_L: alot of edu is
06:28 PM polprog: hmm. my fpga led drivers are still on the slowboat
06:29 PM Tom_L: the container fell off the ship
06:29 PM Tom_L: the dolphins are having fun with it
06:29 PM aandrew: lol
06:30 PM polprog: they are intelligent enough to flash jtag
06:30 PM aandrew: the thought of dolphins coding VHDL makes me smile
06:31 PM polprog: hmm. i havent had time to play with the ics that came last month
06:31 PM polprog: hopefully winter break is soon
06:31 PM aandrew: ics?
06:31 PM polprog: christmas break
06:32 PM polprog: ICs, a couple 4000 series stuff
06:32 PM polprog: pll, flip flop, inverters, counter
06:32 PM polprog: a nice paralell adc
06:33 PM polprog: that would make a cool IO for the eeprom fsm, if i had an eprom fsm
06:33 PM polprog: its on paper now :/
06:33 PM polprog: uv eprom eraser should be here monday ^_^
06:36 PM aandrew: ohhh with the ICs that came last week, as in multiple integrated circuits that you ordered
06:36 PM aandrew: got it now
06:36 PM aandrew: I'm not blonde but that sure felt like it
06:36 PM polprog: :P
06:37 PM aandrew: I'm trying to think what I.C.S. is an acronym for
06:39 PM polprog: allright..
06:39 PM polprog: gotta go to sleep
06:39 PM polprog: were handing in out planet simulator project
06:40 PM polprog: our*
06:40 PM polprog: https://polprog.net/rozne1/ircjunk/mercury.png
06:40 PM polprog: this was a test run a couple days ago
06:41 PM polprog: apparently they added more planets, ill have to check and patch it up
06:41 PM polprog: its nice, small codebase, dead simple
06:41 PM polprog: goodnight :)
07:07 PM rue_mohr: crap
07:07 PM rue_mohr: i did one of the practise quizes and failed at 68%
07:08 PM rue_mohr: then it said the class average was 38%
07:08 PM Tom_L: heh
07:14 PM aandrew: it really sounds like this course is going to be marked on the curve
07:14 PM aandrew: and your classmates are going to lynch you if you don't fall in line
07:16 PM aandrew: oof clearpath contract just got moved up, I am starting on Tuesday
07:17 PM aandrew: what I really want to do is get that CNC set up
07:17 PM aandrew: but home depot hasn't delivered that shelving yet
07:18 PM aandrew: I did get two canadian tire shelves for cheap: https://www.canadiantire.ca/en/pdp/mastercraft-5-shelf-storage-rack-36-x-16-x-72-in-0686447p.html
07:19 PM aandrew: good standard shelving (I actually prefer princess auto https://www.princessauto.com/en/5-shelf-galvanized-steel-shelving-unit/product/PA0008533846 but I don't buy unless it's 50% off)
07:19 PM aandrew: I wouldn't put a CNC on those though, although I do have my 3D printer on one (but the shelf is lashed together with another and there's a lot of weight holding them both down)
08:25 PM aandrew: learning about sound deadening
08:25 PM aandrew: interesting to note that foams are less good than solid (e.g. neoprene)
08:25 PM aandrew: "mass loaded vinyl" seems to be a good search term but it's pricey
08:25 PM aandrew: apparently works wonders under drywall though
08:36 PM rue_mohr: ok I better get back to it
08:46 PM aandrew: good luck
08:46 PM aandrew: lack of motivation day 1234
10:21 PM rue_mohr: ok I'm cooked
11:25 PM rue_mohr: aandrew, that triangle gen
11:25 PM rue_mohr: its.... not an integrator...
11:25 PM rue_mohr: I'm not quite sure but the slew rate is constant regardless of the cap
11:26 PM rue_mohr: that was odd...
11:26 PM rue_mohr: some master must be able to combine a schmidt and an integrator
11:29 PM rue_mohr: I'm not quite siure how he got it to behave like he did
11:30 PM aandrew: I don't pretend to understand it too much but it looks like it is an integrator
11:30 PM rue_mohr: yea
11:30 PM rue_mohr: I know
11:30 PM rue_mohr: I'm still confused
11:30 PM aandrew: if the voltage across the cap is lower than the input then the output is high and the cap charges linearly... then it crosses the threshold and the output swings low, and the cap slowly discharges
11:31 PM rue_mohr: it kept going into a square wave with slow slew rates
11:33 PM aandrew: that's why I said you need to tune the cap and its series resistor carefully
11:33 PM aandrew: if you don't you get a slow slew rate square wave with a flatter (but not flat) slope at the ends
11:37 PM aandrew: https://pastebin.com/FBX1EjJp the very finest in text field validation right there, I tell you hwhat
11:45 PM rue_mohr: hmm
11:46 PM rue_mohr: line[100];
11:46 PM rue_mohr: .....
11:47 PM rue_mohr: hmmm
11:47 PM rue_mohr: I'm sure its easy to add stack code after just 100 chars...
11:48 PM rue_mohr: http://www.learningaboutelectronics.com/Articles/Sine-wave-generator-circuit-with-a-555-timer.php
11:48 PM rue_mohr: :/
11:49 PM rue_mohr: didn't even adjust the duty to 50%
11:49 PM rue_mohr: which is about a 1.5k from 7 to 5
11:50 PM rue_mohr: http://www.learningaboutelectronics.com/Articles/Triangle-wave-generator-circuit.php
11:50 PM rue_mohr: yea, I need a media person