#robotics Logs

Apr 28 2019

12:03 AM rue_shop3: I need to get obsessed about something
12:07 AM rue_shop3: havn't burried my head in a good-ole obsession for a while
12:11 AM rue_shop3: cant get any perspective to work out what to focus on
12:11 AM zhanx: rue_shop3, what do you know about V- and caps
12:14 AM rue_shop3: ok, I COULD write the usb control stuff for my freq gen, then I could sweep filters
12:14 AM rue_shop3: if I shaved, my face would stop bothering me
12:15 AM rue_shop3: I could upgrade the printer beside me
12:15 AM rue_shop3: it would like me for that
12:15 AM rue_shop3: I'd like something I can watch when I'm done
12:15 AM zhanx: rue_shop3, I shaved today, it was looking like a beard
12:15 AM rue_shop3: Mattx, well?
12:16 AM rue_shop3: analog PID
12:16 AM rue_shop3: I could sit down and do that
12:17 AM Mattx: I was trying to put the pieces together, I think I got it
12:17 AM Mattx: makes more sense now
12:18 AM rue_shop3: zhanx, people on twitter saying I'm amazing is throwing me off...
12:19 AM zhanx: rue_shop3, some time next week I need to pick your brain on IMU recording and tolerance from user playback / repeating it
12:19 AM Mattx: and second question you may help with is this, they used passive filters to get rid of high frequencies, would you put active filters instead? why or why not?
12:19 AM rue_shop1: I'm the same me I always was
12:19 AM Mattx: not sure the difference either, I wouldn't know when to use which
12:19 AM rue_shop1: Mattx, I think they were balancing out gain
12:20 AM rue_shop1: the input stage is 500, thats a lot
12:21 AM Mattx: apart from gain no difference for filtering?
12:21 AM rue_shop3: its odd that its a 3 stage filter
12:21 AM Mattx: they could have used an active filter with no gain
12:21 AM rue_shop3: active filters will amplify noise
12:22 AM Mattx: sorry, even with no gain?
12:23 AM rue_shop3: yup, anything active introduces some noise
12:23 AM Mattx: oh, I see
12:23 AM rue_shop3: whats it for?
12:24 AM Mattx: the circuit? its an electrooculogram
12:24 AM zhanx: Mattx, you just trying to learn more?
12:25 AM rue_shop3: huh
12:25 AM Mattx: yep, I'm actually a software engineer, I'm learning electronics for fun
12:25 AM rue_shop3: for a computer interface or?
12:25 AM zhanx: Mattx, you are in the right place then
12:25 AM zhanx: rue_shop3, what did i tell you back in 08 etc
12:25 AM rue_shop3: your power is 50Hz there?
12:26 AM Mattx: rue_shop3, kind of. I'm building a REM detector
12:26 AM Mattx: it's 50Hz right
12:26 AM rue_shop3: ok, cuase you have 60Hz power like us, it needs an adjustment
12:27 AM Mattx: yeah, I noticed the notch filter is right at 50Hz
12:27 AM rue_shop3: analog circuits like that are actually not easy to build and come out properly tuned
12:29 AM Mattx: oh btw, regarding the last part of the circuit... what is the purpose of the voltage follower? I think it is to be able to draw more current but that would be pointless considering there's another opamp right before the voltage follower
12:29 AM Mattx: and there's this voltage divider connected to the v folower too
12:29 AM zhanx: the voltage follower goes to Aref to the chip
12:30 AM rue_shop3: the divider must be soemthing regarding startup state
12:30 AM rue_shop3: the follower will depend on what its being connected to
12:30 AM zhanx: i can kind of answer this
12:31 AM Mattx: https://cdn.makezine.com/uploads/2012/12/m29-eyeboard-circuit-diagram.jpg
12:31 AM Mattx: similar circuit there ^
12:31 AM Mattx: also with divider + follower at the end
12:31 AM rue_shop3: heh, wtf
12:31 AM zhanx: on my current project my boot code drops the voltage hard, so once its back up to spec i continue
12:31 AM rue_shop3: oh an avr
12:31 AM rue_shop3: looked like analog into usb adapter for a sec
12:32 AM * zhanx waits for rue_shop3 to program the avr via ISA
12:32 AM rue_shop3: :)
12:32 AM zhanx: what ever made you think of that anyways?
12:33 AM rue_shop3: the extermination of parallel ports
12:33 AM rue_shop3: which are pretty close to just an isa breakout
12:33 AM zhanx: cause well after that I saw an IBM project with an ISA slot and a ton of features you almost tapped into
12:34 AM rue_shop3: Mattx, the voltage follower on the canadian one is because its comming off the output of the passive filter
12:34 AM zhanx: rue_shop3, look at the input pin on the avr for it
12:35 AM Mattx: and that produces a voltage drop they're compensating?
12:35 AM rue_shop3: no, a passive filter like that has a really high impenence output, they are stiffenign it up
12:36 AM rue_shop3: cute
12:36 AM rue_shop3: the canadian one, runs +-5V by grounding from the first 5V regulator
12:36 AM rue_shop3: I think everyone is copying and modifying with no idea what their doing
12:37 AM rue_shop3: INA118....
12:37 AM rue_shop3: that sounds familiar...
12:37 AM Mattx: instrumentation ampl
12:37 AM zhanx: i need a better wifi router, all this smart home stuff is killing it
12:38 AM rue_shop3: mine are INA101
12:38 AM rue_shop3: huh
12:38 AM rue_shop3: zhanx, no, wireless just sucks
12:38 AM Mattx: I don't have one at hand, I had to build my own with 3 opamps :(
12:39 AM zhanx: well i have all the lights, outlets, refrig, 3 freezers etc on it
12:39 AM Mattx: hope it behaves in the same way
12:39 AM zhanx: plus the computers
12:39 AM rue_shop3: my understanding is that they are touchy to build
12:39 AM zhanx: phones. tvs
12:40 AM rue_shop3: you should have seen my launghing when, at work, they loaded up the company wifi with 4 streaming webcams that pushed the data to a cloud and then complained the internet didn't work anymore
12:40 AM zhanx: rue_shop3, and my garden net is not even up yet
12:40 AM rue_shop3: everything about the internet connection had to be upgraded just to make it barely work
12:40 AM zhanx: I am thinking about hardwiring it this year to the greenhouse
12:42 AM rue_shop3: Mattx, interesting that nobody put electrostatic protection on their amplifier inputs
12:42 AM Mattx: what kind of protection?
12:42 AM rue_shop3: for static electric discharge
12:42 AM Mattx: <zhanx> the voltage follower goes to Aref to the chip
12:42 AM Mattx: not really, what are you looking at?
12:43 AM rue_shop3: all of them
12:43 AM Mattx: rue_shop3, but is it drawn in schematics? maybe they did but it's not in there
12:43 AM zhanx: Mattx, pin 21
12:43 AM rue_shop3: its kinda a rule that anything users can touch needs electrostatic protection
12:44 AM Mattx: zhanx, I think aref is connected to the regulator not the voltage follower
12:44 AM Mattx: the labeling is just misplaced
12:44 AM zhanx: Mattx, no look at pin one
12:44 AM Mattx: the v follower is the opamp below the label, it has nothing to do with the aref
12:45 AM zhanx: k
12:45 AM zhanx: looks to me like it is
12:45 AM zhanx: due to battery power
12:45 AM rue_shop3: hmm, whats the max gain of my scope...
12:45 AM zhanx: I know its usb but that still bounces
12:46 AM Mattx: didn't get the purpose of the voltage divider yet
12:46 AM zhanx: cause i don't know the draw on the circuit i can code it to compensate
12:46 AM Mattx: the one involving R8 and R9 in one of the circuits
12:47 AM Mattx: R16 and R7 in the other
12:47 AM Mattx: same value for the resistors (11M), I wonder if one copied the other
12:47 AM Jak_o_Shadows: Mattx/Rue, is this the sort of thing simulations can help with?
12:47 AM Jak_o_Shadows: spice or whatever?
12:48 AM Mattx: don't know spice, no idea
12:48 AM zhanx: Jak_o_Shadows, I think Tom_L does the spice stuff
12:48 AM rue_shop1: not when your hooking it up to a human
12:49 AM zhanx: or was it orlock
12:49 AM Jak_o_Shadows: But you'd get some idea of something.
12:49 AM Mattx: is it reliable to simulate circuits like this?
12:49 AM Mattx: maybe not the human connection haha
12:50 AM Mattx: but I can plug an artificial signal I guess
12:50 AM Jak_o_Shadows: I think it's ok? the only thing is how the physical construction changes thing
12:51 AM Mattx: we're talking about ltspice right?
12:51 AM Jak_o_Shadows: I am not mentioning anything in particular, it's not something i'm more than passing familiar with
12:51 AM Mattx: I see, spice is the simulator, ltspice is just one of the guis
12:58 AM Mattx: looks really promising
12:59 AM Mattx: have you used it for anything complex? experiences?
12:59 AM Mattx: any of you
12:59 AM zhanx: not me
01:00 AM zhanx: not like i shouldn't my current project is nice
01:02 AM Mattx: what're you doing?
01:02 AM zhanx: autism helper thing for my wife's office
01:04 AM zhanx: Mattx, my wife is an office admin for a psychological clinic etc
01:05 AM Mattx: this EOG thing is interesting for computer interfaces based on eye movements, now that you mention clinics
02:01 AM Mattx: what kind of notch filter is this?
02:01 AM Mattx: http://onloop.net/hairyplotter/images/final_eog_ckt.png
02:02 AM Mattx: It's not a twin-t notch
02:13 AM Mattx: it's similar to a twin-t notch except it has an extra capacitor and it's not grounded, weird
05:13 AM Moistmelon is now known as Wetmelon
10:40 AM SomeT: anyone know of the best 2D robotics simulator?
10:40 AM SomeT: does not matter as to which OS or programming language
10:40 AM SomeT: a recently updated one is beneficial however
11:23 AM rue_bed: as long as your nt trying to use it for anything real-world, use anything
11:30 AM SomeT: could you please elaborate on anything?
11:30 AM SomeT: because technically I could use a game engine
11:30 AM SomeT: where this is not viable, different to a robot simulator perhaps?
11:41 AM rue_bed: well, its an important distinction.
11:41 AM rue_bed: if its a school project use a game engine, there will be better support
11:41 AM rue_bed: if its real world, dont simulate it, it wont work the same
12:08 PM SomeT: ah ok
12:58 PM deshipu: veverak: what does "fuk" mean in Czech?
12:59 PM SomeT: hello
01:41 PM veverak: deshipu: either short of fuck or in sentence "to je fuk" which is "it is unimportant", the fuk is the "unimportant
01:45 PM mrdata: like english,, fuck all
01:45 PM mrdata: nothing important
02:04 PM deshipu: veverak: how about in "Čury mury fuk"?
02:05 PM deshipu: I know "czary mary" in Polish, but "fuk"?
02:32 PM justan0theruser is now known as justanotheruser
03:47 PM durrf2 is now known as durrf
04:57 PM rue_shop3: I think I want to make a freq sweep filter profiler
05:03 PM Tom_L: what's that do?
05:24 PM rue_shop1: freq sweep a filter to profile it
05:25 PM Tom_L: we talked about those molds before didn't we?
05:25 PM Tom_L: did i make a drawing?
05:25 PM Tom_L: i can't remember but though maybe i did
07:29 PM rue_mohr: not for triggers
07:29 PM rue_mohr: we did a thing for the latches
07:41 PM Tom_L: oh
07:57 PM Tom_L: what PN is it?
07:57 PM Tom_L: A3
08:00 PM Tom_L: i wonder if i made some of those, i have a program for them
08:01 PM rue_mohr: you were playing with it I think
08:01 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/rue/Can_Holder/A3/A3_1.jpg
08:01 PM Tom_L: guess so
08:02 PM Tom_L: i must have sent you some
08:02 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/rue/Can_Holder/A3/A3_P2.jpg
08:02 PM Tom_L: hmm
08:03 PM rue_mohr: ? no, not that I recall...
08:03 PM rue_mohr: 3 cuts, wow
08:03 PM Tom_L: alot?
08:03 PM rue_mohr: I have to do passes about .2mm at a time
08:04 PM Tom_L: oh
08:04 PM Tom_L: i may have a bag of 'rue' parts.. lemme check
08:05 PM rue_mohr: heh
08:08 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/rue/bag_o_parts.jpg
08:15 PM rue_mohr: ! oh wow
08:16 PM rue_mohr: thats a lot of latches!
08:17 PM Tom_L: is that the little one?
08:17 PM rue_mohr: yea
08:17 PM Tom_L: i had it set up so i ran a few
08:17 PM Tom_L: didn't take that long
08:17 PM rue_mohr: :)
08:17 PM rue_mohr: the slotting takes us a while
08:18 PM rue_mohr: less thanks to that jig
08:18 PM Tom_L: oh i remember now, i was messin with the thin ness of the full cutout so i could just punch them out
08:18 PM Tom_L: slots go quick here
08:20 PM Tom_L: https://www.youtube.com/watch?v=lNJXA3Qv2i4
08:20 PM Tom_L: i could optimize the program some
08:20 PM zhanx: waiting in queue to start some webhosting
08:21 PM Tom_L: that wasn't the best setup for those but it works
08:23 PM Tom_L: i screwed a few of those up on P1 cause the plate wasn't flat
08:24 PM Tom_L: https://www.youtube.com/watch?v=LO2AvRVU0iE
08:24 PM Tom_L: that was before i got my good vise...
08:24 PM Tom_L: been a while
09:35 PM rue_shop1: ooo ultrasonic levitator...
10:41 PM rue_mohr: https://makezine.com/projects/micro-ultrasonic-levitator/