<wpwrak>
"well, when I want something dissolved, I dissolve it" :)
<whitequark>
hehe
<whitequark>
ok. I finished etching and H2O2 doesn't make a iota of difference
<whitequark>
except some cool visual effects
<wpwrak>
how strong is your peroxide ?
<whitequark>
3%
<whitequark>
I poured an entire 100ml bottle there
<wpwrak>
well, 3% isn't very strong. you poured mainly water. so if the reaction already had an oxidizer before, the difference should be minor
<whitequark>
yeah, you're right here
<wpwrak>
you could go to stronger peroxide, though. e.g., with HCl, 3$ is pretty tame. with 35% the copper is gone in a few seconds (while the acid happily boils and fumes)
<whitequark>
yeah, I think I'll place a second order at that reagent vendor, buy proper peroxide and those organic copper salts to test various activation methods
<wpwrak>
35% is great to refresh an old solution without adding a lot of water, though. a few ml in maybe 1-2 dl and it's good to go again
<whitequark>
wpwrak: by the way, defects from yesterday seem to be insufficient toner density
<whitequark>
because today they were at pretty much same places
<whitequark>
so it's a defect of photomaster. not a defect of exposition, since they;re not systematic
<wpwrak>
in this case, my acid is getting too diluted and i would need too much peroxide to reactivate it. so for the next board, i'll move about half of the acid to long-term storage. then the rest will be easier to maintain.
<wpwrak>
well, you see the broken traces ... :)
<whitequark>
btw, do you not use resist because it's hard to get through customs?
<DocScrutinizer05>
the copper around the pre-drilled holes looks terribly rotten
<whitequark>
DocScrutinizer05: on which board?
<wpwrak>
i just didn't like the complex process. i think materials should be available locally.
<wpwrak>
yes, the vias holes are crap. actually, that's not a problem of the etching but of the drilling - i was too lazy to change bits, so i just did them with the endmill, which is too large for that
<wpwrak>
bit since they're all very trivial anyway, ...
<wpwrak>
ah, his board :)
<whitequark>
DocScrutinizer05: true. I screwed up with drilling the holes a bit, and poor etching exacebrated it
<whitequark>
had built-up edge
<DocScrutinizer05>
either no drilling before etching, or at least seal holes with e.g. wax after drilling
<wpwrak>
ah no, now i remember. it wasn't the endmill but a wider drill i had used for the pogo pins. anyway, same result - the vias ended up half-eaten
<DocScrutinizer05>
it looks like under-etching combined with poor attachment of PhRe
<whitequark>
board on right: really clean. board on left: not so
<DocScrutinizer05>
also PCB copper isn't exactly smooth and plane anymore, around holes
<whitequark>
DocScrutinizer05: yeah, I see; and I now look at photo closely and it seems copper edge penetrated resist
<whitequark>
I need to do something with it...
<wpwrak>
whitequark: btw, the trace width seems correct within the resolution of the image. i get 253 pixels for 7*0.5 mm, which would make 0.2 mm 14.5 pixels. i measure around 15-17 pixels. also, the image resolution isn't very good.
* DocScrutinizer05
wonders where been that info about etching time and under-etching
<DocScrutinizer05>
might even have been about chip manufacturing
<DocScrutinizer05>
and how thex manage to either get trapezoid or perpendicular walls of their traces
<DocScrutinizer05>
they*
<DocScrutinizer05>
there happen a few pretty non-intuitive things
<DocScrutinizer05>
they can even etch inverse trapezoid, though it's mostly useless. don't ask me how they do that
<DocScrutinizer05>
maybe gas protecting the material that gets etched? gas originating from etching process and moving up?
<whitequark>
hmmm
<whitequark>
no clue
<DocScrutinizer05>
or thermal fluid convection, covering material way up with a film of "inert" fluid?
<DocScrutinizer05>
anyway I seem to remember: the longer the etching takes, the worse the trapezoid problem
<DocScrutinizer05>
http://www.mikrocontroller.net/topic/157206 >>... aber man kann ja durch die schnelle Aetzgeschwindigkeit einen hoeheren Aetzfaktor (weniger Unteraetzung) erwarten und somit feinere Strukturen erzielen.<<
<whitequark>
yep, the trapezoid appears due to concurrent etching in perpendicular and parallel direction to copper
<whitequark>
I probably should've cleaned the board better before attaching mask
* DocScrutinizer05
just pondered about replacing the photosensitive roller in laserprinter by the PCB with PhPos
<DocScrutinizer05>
nice hw mod to a laserprinter
<DocScrutinizer05>
basically should be pretty straight forward to design
<whitequark>
um... doesn't sounds simple to me at all
<whitequark>
first it's the wrong frequency, you'd need to redo its optics completely
<whitequark>
1) it likely uses glass -> uv-opaque
<whitequark>
2) it's all designed to handle freq it uses. others will refract in a different way thus distorting the picture
<whitequark>
so you'd need to make a custom frensel lens
<whitequark>
at least
jow_lapt1p is now known as jow_laptop
<DocScrutinizer05>
just rip out all unneeded gear from laserprinter. Cover photosensitive roll with a 0.2mm of rubber. move laser scanner unit a ~1mm away from the roller
<DocScrutinizer05>
ooh, wrong laser color. Right
<whitequark>
though that for sure would be a cool hack
<DocScrutinizer05>
:-/
<DocScrutinizer05>
a pity
* DocScrutinizer05
heads out for more coffee
<whitequark>
iirc toxicity limits for coffee is about 100 cups per day
<whitequark>
have you ever came close? :D
<DocScrutinizer05>
yeah once
<whitequark>
wow
<whitequark>
seriously?
<DocScrutinizer05>
I created a normal coffe cup full of ultra espresso made from ~300g of coffee powder - the machine was designed to produce a whole can of coffee the espresso way, I used it for a cup
<DocScrutinizer05>
felt pretty sick after drinking that
<DocScrutinizer05>
I been 18 or 19 when I did that
<DocScrutinizer05>
so qite a while ago
<DocScrutinizer05>
quite*
<DocScrutinizer05>
attribute it to my mind developing phase, according to what we discussed yesterday ;-)
<whitequark>
that's probably even more than 100 cups
<whitequark>
sure, sure
<whitequark>
I can understand doing crazy stuff, I'm just amazed at the magnitude
<DocScrutinizer05>
it's really amazing I'm still alive
<whitequark>
there was a gif somewhere...
<pcercuei>
some guy died not so long ago after eating caffeine
<DocScrutinizer05>
when I was 4 or 5, I walked from one window to the next - in the rain gutter. We lived in top floor of that building back when
<DocScrutinizer05>
seems I must've been kinda natural born crazy
<whitequark>
I knew a cat who liked to jump from one window to an adjacent balcony
<whitequark>
about five times that ended with a plunge down 4 stories
<DocScrutinizer05>
for me it luckily didn't ;-)
<whitequark>
that cat eventually died after five traumatic injures, ovary cancer, failed pregnancy, infection and who knows what else, when I was 19
<whitequark>
and I'm pretty sure the cat was actually older than me
<whitequark>
she was a street cat, taken in at several months. Guess she needed good genes to survive in RU :)
<DocScrutinizer05>
cats have 9 lifes
<DocScrutinizer05>
seems yours used up all of them finally
<whitequark>
19 is waaaay higher than usual cat life expectancy though
<whitequark>
though it is not unheard of humans who smoke, drink and generally have fun, and then live to 105 years
* DocScrutinizer05
still can't let go on the laserprinter mod
<whitequark>
hm
<whitequark>
idea: correct for distortion in software
<DocScrutinizer05>
just pondered that
<whitequark>
refractory distortion. you can make a grid pattern, scan it and then apply affine transform
<DocScrutinizer05>
get a proper 1W blue laser instead of the IR
<whitequark>
UV laser maybe?
<whitequark>
I think there are UV semiconductor lasers
<whitequark>
waitwait, laser printers use IR lasers?
<DocScrutinizer05>
also maybe worth to first check how much this effect of changed optical properties of lenses from changed color +really* kicks in
<DocScrutinizer05>
whitequark: dunno
<DocScrutinizer05>
I think I seen "IR-Laser" label in some manual last week(?)
<DocScrutinizer05>
maybe they use red
<DocScrutinizer05>
IR is cheaper and usually stronger
<DocScrutinizer05>
I know of UV LEDs, but not of UV lasers
<whitequark>
ah, seems it's ongoing research as of 2013
<DocScrutinizer05>
~400nm is what I seen
<whitequark>
"Nitride semiconductors offer the potential to realize a compact UV laser source. Three approaches will be described: (1) InGaN VECSEL for frequency doubling, (2) photo-pumped AlGaN lasers (to 237 nm), and (3) AlGaN laser diodes."
<whitequark>
400nm is exactly what you need
<whitequark>
I use 395nm
* DocScrutinizer05
plays with his 405nm laserpointer
<DocScrutinizer05>
10mW, Class IIIb :-o
<whitequark>
that should work fine
<whitequark>
resist isn't too selective
<DocScrutinizer05>
thought as much
<whitequark>
though, hmmm, UV diodes have a bit of smooth spectrum
<whitequark>
whereas lasers usually have it rather narrow (duh)
<whitequark>
I wonder if that may affect it
<DocScrutinizer05>
damn! Wavelength: 445nm nominal center
<DocScrutinizer05>
already seen offset in paste stencil
<whitequark>
not quite, this chip has bent pins, I missed it
<DocScrutinizer05>
ooh
<whitequark>
however it has good contact still
<DocScrutinizer05>
sure
<whitequark>
okay... need to populate thru-hole and hook up a programmer
<whitequark>
and that's all!
<DocScrutinizer05>
PCBA almost hides the bumpy ugly traces :-)
<whitequark>
I started making this PCB almost exactly 5 hours ago
<whitequark>
so that's pretty nice RTT
<DocScrutinizer05>
indeed, and quite shiny result
<whitequark>
if I figure a way to make silkscreen, it would be basically just like factory stuff
<whitequark>
... and I think I just thought of a way to make it
<DocScrutinizer05>
some chinese crap can go weep in a dark corner, but they gonna sell their stuff nevertheless
<whitequark>
(chinese crap) not sure what was this remark about
<DocScrutinizer05>
toner transfer with color toner?
<whitequark>
(toner transfer) color laser printer costs a fortune, and just to print white toner?... meh
<DocScrutinizer05>
(chinese crap) was about some boards from china that look really ugly compared to yours
<whitequark>
(china) so I'm not the lowest link in food chain. encouraging :)
<whitequark>
(silkscreen) well, I could just use... silkscreen!
<DocScrutinizer05>
yellow toner, b&w printer
<whitequark>
problem with toner is, it's not really heat-resistant, scratches easily, doesnt like solder/flux and all that
<whitequark>
same concerns about "solder mask" out of toner
<DocScrutinizer05>
right
<DocScrutinizer05>
soooo
<whitequark>
so, silkscreen. I need to find a sheet of something with tiny holes or maybe woven
<whitequark>
then I can just use my existing resist, run it all through laminator. when heated, resist basically flows like a viscous liquid
<whitequark>
so it will flow into those holes
<DocScrutinizer05>
silk maybe ;-)
<whitequark>
wont survive 120°C laminating
<DocScrutinizer05>
err, laminate?
<whitequark>
well, attaching resist
<DocScrutinizer05>
with heat?
<whitequark>
yep. I don't want to bother with liquid resist, it's quite horrible to use. dries for a long time, hard to get nice layer, nasty chemicals
<DocScrutinizer05>
I guess I have no idea what you're planning
<whitequark>
well... like regular silkscreen, with some modern polymer instead of "silk" (neoprene?) and dry film resist pushed into matrix with my laminator
<whitequark>
then I expose and develop it, then like in regular silkscreen, I push white ink through holes
<DocScrutinizer05>
what the heck is dry film resist?
<DocScrutinizer05>
yeah, and an excellent tutorial "how to solder wires to pads"
<apelete>
whitequark: what kind of techniques and tools are you using to achieve that ?
<whitequark>
apelete: can you ask more specifically?
<whitequark>
I mean, I could start to explain one by one but that'll take a few hours
<whitequark>
do you mean those wires?
<DocScrutinizer05>
well, I can tell you're most likely right-handed
<apelete>
looks like the strand is comforatably sitting in the drop of tin, and the rubber is not even burned near the end of the strand
<DocScrutinizer05>
the result of good tools and material and right temperature
<whitequark>
apelete: so... the wire was pre-tinned, it's a lead of a battery holder. however if you tin it very quickly and with iron at say 190°C, you can manage to have rubber intact
<whitequark>
the PCB pads were pre-tinned too, here it was chemical tinning process. A factory-made PCB would have it pretinned or with some other good coating. A self-made PCB you really need to tin yourself well
<DocScrutinizer05>
you always should tin the pad, then just reflow wire to it
<whitequark>
then I just dropped a small drop of PbSn 60/40 solder there, so it made a nice small bulge
<DocScrutinizer05>
I called it bead
<whitequark>
then I held the wire on top of that bulge and heated it with iron for no more than 1-2s
<DocScrutinizer05>
my words :-D
<whitequark>
in this case I had iron turned up to almost 300°C
<apelete>
could you tell me more about the tinning process for the pads, what are you calling "chemical tinning process" ?
<whitequark>
I bought a liquid called "liquid tin" locally, it's some salt of tin according to label
<DocScrutinizer05>
apelete: you don't want to know about that - now
<whitequark>
I put the well-cleaned board into it for 30 minutes--again according to label--and tin laye grows on exposed copper
<whitequark>
*layer
<DocScrutinizer05>
it's advanced stuff you don't need
<whitequark>
it looks a bit ewww (dark grey), but solder attaches to it really really well
<DocScrutinizer05>
nothing flux and good solder wire couldn't do
<whitequark>
^ that. I used to use RMA flux and PbSn solder before
<whitequark>
it's more work and you have to clean the flux, but you'll be 100% fine with that
<DocScrutinizer05>
ack
<apelete>
whitequark: okay, so once you have your drop of solder on the pad, you just push the wire into it with the iron ?
<whitequark>
one thing to remember: don't be greedy on flux
<whitequark>
better to drown board in flux than put not enough
<whitequark>
apelete: I placed the wire *on top* of the bead, then gently pushed it down with my fingers
<whitequark>
while holding
<whitequark>
then I started to heat it and when solder begins to flow to the wire due to surface tension--I remove iron
<whitequark>
and wait several seconds to let solder solidify
<whitequark>
you really mustn't move the wire immediately after removing iron or you'll get bad contact
<DocScrutinizer05>
this is important! don't move things while solder curing!
<DocScrutinizer05>
not a micron
<whitequark>
*nod*
<apelete>
I think I need practice and a magnifying glass to see things closeup
<DocScrutinizer05>
thus you usually prefer a setup where you don't need to *hold* the wire (or other component). Humans can't NOT move
<DocScrutinizer05>
it needs extreme practice to solder a wire you#re holding by hand
<whitequark>
yup, I sometimes clamp the wire with something
<apelete>
if there's already a drop of solder on the pad and the wire is tinned, I should only need two hands: one holding the iron, and other pushing the wire
<apelete>
right ?
<DocScrutinizer05>
I'd almost say it's impossible to do it right
<whitequark>
DocScrutinizer05: that's a bit exaggerated...
<DocScrutinizer05>
you need flux and a clamp so the wire stays on top of bead without your hand holding it
<DocScrutinizer05>
so you basically should get the job done using only one hand
<DocScrutinizer05>
trying to work two-handed is not exactly simple
<apelete>
DocScrutinizer05: I actually needed three hands yesterday...
<DocScrutinizer05>
then you can't achieve a good solder point
<whitequark>
I have exactly that thing as you can see
<DocScrutinizer05>
yup, I think I also have exactly this
<wpwrak>
those things many times don't really help either. if the wire is very flexible, you can't push it down properly with this
<DocScrutinizer05>
haven't used it for quite a while
<apelete>
yes, was thinking about buying something similar
<DocScrutinizer05>
wpwrak: that's the trick
<whitequark>
wpwrak is right about flexible wire. also that may not be convenient to hold by hand, since it can get hot very quickly
<whitequark>
so, I use curved tweezers for that
<whitequark>
wtf, PSU still won't come on
<DocScrutinizer05>
borked
<DocScrutinizer05>
:-/
<wpwrak>
i've given up on these critters and only use them when i'm running out of hands. the solder joints still seem to be stable enough :)
<whitequark>
DocScrutinizer05: ... no
<DocScrutinizer05>
wpwrak: with years of practice...
<whitequark>
borked is the cable
<whitequark>
somehow the PSU has a weird variant of standard PC 3-prong connector
<whitequark>
which accepts about half of cables I own
<apelete>
tweezers ! that would have help yesterday, discovered that my fingers were way too big ;-)
* DocScrutinizer05
has roundabout 20 tweezers
<DocScrutinizer05>
all shapes and types
<DocScrutinizer05>
some of them cost 20 bucks
<DocScrutinizer05>
other 20 a buck
<DocScrutinizer05>
both work, in the particular case where they fit
<DocScrutinizer05>
I found a number of contraptions quite useful, where you solder two of those crocodile clamps to the ends of a 1.5mm^2 copper wire, and bend that thing the way you need
<DocScrutinizer05>
clamp one croc to the PCB edge, other end holding wire to solder
<DocScrutinizer05>
mad useful
<DocScrutinizer05>
also fine to make short connections
<DocScrutinizer05>
like: attach a LED+resistor to a 9V block, or the like
<DocScrutinizer05>
3..10cm length of wire are fine
<DocScrutinizer05>
usually 5cm is what I like best
<DocScrutinizer05>
>>WARNING: One unit has been found to have been dangerously mis-wired:<< LOL, well that's what you get from incredibly cheap chinese stuff
<whitequark>
okay... hm, what to do for the rest of today. I think I need to add pcb-gcode generator for silkscreen and try the acrylic paint idea
<DocScrutinizer05>
I think you want to check your CNC controller, no?
<whitequark>
oooh right, thanks, that's a good idea
<whitequark>
still I'm off to get some food and paint. can't buy 'em at 1AM
<DocScrutinizer05>
that's also a good idea, should do similar
<DocScrutinizer05>
oooh right, no shower until those dudes finished their epoxy mess in our sewage
<DocScrutinizer05>
:-S
<wpwrak>
now that's a convenient excuse ;-)
<DocScrutinizer05>
it actually sucks
<whitequark>
no shit
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<DocScrutinizer05>
I've been told they only have to get 5 leaks done today, so can't take much longer
<DocScrutinizer05>
Thu and Fr they were busy whole day
<DocScrutinizer05>
it#s quite strange they don't give any links to true spec sheets of the dang MCU
<wpwrak>
F4 is a lot more powerful than L1
<wpwrak>
btw, i'm not sure how well these boards play with open tools. you have that st-link that may be an obstacle.
<DocScrutinizer05>
I don't care, it's for free
<DocScrutinizer05>
I'll get the F4 then
<DocScrutinizer05>
the "term and conditions" is an empty webpage ;-P
<wpwrak>
the chips hmm, the F4 should have two USB ports. i don't see them ...
<DocScrutinizer05>
meh
<wpwrak>
the F4's boot ROM supports DFU. so that's a convenient way for flashing firmware. you also need a reset button and a way to switch the boot mode selection.
<DocScrutinizer05>
FUCKIT! "Max quantity reached. Please contact your distributor"
<DocScrutinizer05>
shouldn't waste my time on such crap
<wpwrak>
;-)
<DocScrutinizer05>
or should've filled the form 5 days ago, when I first opened the page
<wpwrak>
it's some weird design for the arduinobotomized anyway
<DocScrutinizer05>
meh, 10 USD
<DocScrutinizer05>
I probably should feel grateful that this thing doesn't clutter my flat
<wpwrak>
if you want fun and something to relax with from the hard work on neo900, why not play with, say y-box ? also has a nice little arm, and even an rf chip
<DocScrutinizer05>
no time for such stuff
<whitequark>
wpwrak: I wrote adapter for st-link
<wpwrak>
they work you too hard in the neo900 mines, do they ? :)
<DocScrutinizer05>
prolly only when we fix a time and location
<whitequark>
okay, got some paint
<whitequark>
consultant woman was probably quite surprised when I told "I want white acrylic paint with hi-temp resistance for PCB silkscreening"
<whitequark>
still she pointed me to "regular" TiO2/ZnO based ink -- I took TiO2 'cause ZnO can be quite reactive, e.g. with trace amounts of H2S it becomes black
<whitequark>
and to some crap for painting on ceramic, labelled stable at 150°C for 15 min
<whitequark>
however that last thing is quite liquid so I may have a hard time getting it through silkscreen
<whitequark>
also, expensive: $1 per 15ml
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<whitequark>
side note: I'm really enjoying proper stencils, placing solder paste used to be such a horrible PITA for me, I hated it
<whitequark>
and now it's done in less than a minute
<whitequark>
not to mention there's no solder bridges
* DocScrutinizer05
hopes for proper howto
<DocScrutinizer05>
even video maybe
<whitequark>
DocScrutinizer05: I'm absolutely going to describe the whole process in excruciating detail
<DocScrutinizer05>
:-)
<whitequark>
all materials, precise instructions, photos of every step and such
<whitequark>
that's why I got myself this nice camera and so.
<whitequark>
but first I want to a) debug the shit I still have broken (etching mainly)
<DocScrutinizer05>
the camera is really nice
<whitequark>
b) get to two-side PCBs with throughhole plating
<DocScrutinizer05>
makes good macro shots
<whitequark>
well I paid almost $300 for this macro lens
<whitequark>
no doubt it makes good macro shots!
<DocScrutinizer05>
aaah#
<whitequark>
and roughly same sum for camera and a tripod
<whitequark>
good tripod is absolutely *required* for good macro shots
* DocScrutinizer05
wonders how and which lens to attach to his fuji XQ1
<whitequark>
I *think* you can't stack optics like that and get good results. but I may well be very wrong.
<whitequark>
(can't) due to stuff like aspherical correction your camera implicitly does (it doesn't give you raw files, rather with a huge amount of postprocessing)
<whitequark>
choke and thing on right is a buck converter yeah
<whitequark>
but it only provides logic supply for discrete stuff on board and stepper drivers
<whitequark>
not motor supply
<DocScrutinizer05>
the TB6560AHQ is using PWM to adjust the current thru motor
<whitequark>
oooh
<whitequark>
got it
<DocScrutinizer05>
usually the current should ramp up when motor spins, and when it stops the current gets reduced to so called "hold current" that keeps motor on position
<whitequark>
wtf. look at that board, I just noticed: the traces to three supposedly identical driver circuits are all different width
<whitequark>
and its basically random
<DocScrutinizer05>
so low noise might mean it isn#t actually stopped but constantly stepping back and forth
<whitequark>
(back and forth) that I could feel as vibration of the plastic handle attached to its axis, no? and axis is completely still
<whitequark>
I think that's just PWM of hold current making the windings vibrate
<DocScrutinizer05>
if it's one microstep, I doubt you could feel it
<whitequark>
ok. I'm entirely lost. if I unplug either X *or* Y motors, the high-pitched noise stops
<whitequark>
otoh X motor always emits low-pitched noise regardless of channel it's plugged in
<whitequark>
actually, all 3 channels make motors emit their own unique kinds of noise
<whitequark>
recognizable by ear
<whitequark>
low-pitched noise that is
<DocScrutinizer05>
you won't get anywhere without a scope, friend ;-)
<whitequark>
:(
<whitequark>
hm, lemme check if anyone sells worthwile stuff locally
<whitequark>
oh god it's like 1970s all over again
<DocScrutinizer05>
on the bright side: for your special problem your PC's audiocard makes for a perfect dual chan scope
<DocScrutinizer05>
the 2445 is a tank, very convenient to operate
<DocScrutinizer05>
while digital scopes often are extremely clumsy with an abysmal man machine interface
<whitequark>
(c't hacks article) yeah but my german's not quite well enough atm :)
<whitequark>
it also seems either of my options here is above range of that article
<DocScrutinizer05>
that doesn't matter. What they tell you in that article is basics that always apply
<DocScrutinizer05>
also, really? I can't figure how a 500$ is above the range of that article
<whitequark>
well, okay, prolly not
<DocScrutinizer05>
I think their range been 500 to 2500
<DocScrutinizer05>
for used ones
<DocScrutinizer05>
so exactly your range
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<DocScrutinizer05>
for me the 422$ 2445 was a nobrainer
<DocScrutinizer05>
unless i had a 3k to burn for fun
<whitequark>
so you much prefer it to digital scope?
<roh>
we do basically everything with a dso
<DocScrutinizer05>
looking at tds520c I see only 3 dials
<roh>
smaller, lighter, faster.
<roh>
we still got an analog one, but never use it
<whitequark>
I'm just thinking, my typical use case for a scope is capture and then analyze in detail
<whitequark>
that can only work with digital. maybe I'm just wrong here
<DocScrutinizer05>
sure, that's why you can get great analog scopes for cheap money
<roh>
whitequark: get a digital one. analog ones come for free.
<DocScrutinizer05>
whitequark: your typical usecase is to analyze periodic signals. One shot storage is not as useful as it may sound. pretty hard to set up
<DocScrutinizer05>
and actually an analog scpe usually is way faster, so you better see glitches in a periodic signal
<DocScrutinizer05>
s/better/easier/
<qi-bot>
DocScrutinizer05 meant: "and actually an analog scpe usually is way faster, so you easier see glitches in a periodic signal"
<DocScrutinizer05>
dso tries to simlate that called "digital phosphor"
<whitequark>
okay I get your point
<DocScrutinizer05>
a real analog scope beats digital ones hands down on that
<DocScrutinizer05>
sure, when you're used to a dso you probably can use it same way as an analog one and it gives you all a analog one can give you (though with more effort to set up stuff), plus more
<whitequark>
roh: so if you had tds1002 (60MHz 1GS/s 2ch 2k5 samples, $420) and tds520c (500MHz 1GS/s 4ch 250k, $700), what would you choose?
<whitequark>
okay, now I typed that, it sounds silly
<DocScrutinizer05>
dnag, if that things isn't fsckd up fubar, I sell my PC to get it
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<DocScrutinizer05>
but that's simply too cheap
<whitequark>
it's refurbished apparently. vendor says you can check it and have a week to get full refund in case of any problems
<whitequark>
you're encouraged to check it, even
<DocScrutinizer05>
duh!
<whitequark>
there are no probes though
<DocScrutinizer05>
well
<whitequark>
they're listed separately
<whitequark>
whatcha think about it? I can prolly afford it now
<DocScrutinizer05>
get it
<whitequark>
a RU friend says, "it's extremely unlikely it is actually calibrated well"
<whitequark>
still worth a look
<whitequark>
ok I'll chat with them tomorrow
<DocScrutinizer05>
that's true
<DocScrutinizer05>
I can't think how a scope in good condition goes for 10% of its current worth
<DocScrutinizer05>
HMMMM
<whitequark>
do note they can't prolly sell it outside of RU, due to same customs regulations preventing me from buying one
<DocScrutinizer05>
>>Note that it is a 'D' version, which does NOT have the electrolytic capacitor plaque problem at this age, which means this unit is very reliable.<<
<whitequark>
and vendor from avito says it passes POST fine
<whitequark>
guess it's refurbished
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<roh>
whitequark: hmm.. hard question. i guess the 1002.. even when i prefer 4 channel ones. simply because its cheaper and more portable
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<roh>
for debugging fast stuff one needs one or 2 devices capable of handling multi-hundred mhz tho.. so.. having some devices around is never bad.
<roh>
we got i think one 60mhz 4 channel tek, one 500mhz 4 channel heavy tek, one 100mhz 4 channel welec and some other tek which needs fixing. and an old 20mhz ananlog hameg
<whitequark>
yeah, 520c is quite massive
<whitequark>
but I can only get one though
<roh>
the heavy, long and bulky. if you have the space behind your working desk....
<whitequark>
44 cm long, 14 kg
<whitequark>
well... that takes about half of my desk
<whitequark>
by length that is. so it's kinda ok
<whitequark>
actually yeah, I have where to place it
<DocScrutinizer05>
oooh 20MHz Hameg! <3
<DocScrutinizer05>
:-3
<DocScrutinizer05>
whitequark: don't you have shops where you can borrow equipment like that? to get a feeling what you'd like to use?
<whitequark>
they usually work with businesses only
<whitequark>
so not available for me in essence
<DocScrutinizer05>
yeah :-/
<DocScrutinizer05>
honestly, the tek has too few knobs
<whitequark>
which of?
<whitequark>
we've only discussed teks :)
<DocScrutinizer05>
the dso
<DocScrutinizer05>
it's a damn difference to just turn a dial to adjust sensitivity, timebase, trigger, brightness
<whitequark>
mhmm
<DocScrutinizer05>
or to push 3 or four buttons to set one multi purpose dial to the function you want to change
<DocScrutinizer05>
you can live with it, but it's no joy
<DocScrutinizer05>
but maybe i'm simply too old and thus biased
<whitequark>
I can see what you mean
<whitequark>
well... it has separate knobs for H/V scale/position, and trigger level
<DocScrutinizer05>
does it?
<DocScrutinizer05>
I see only 3 dials
<whitequark>
reading the manual
<whitequark>
it actually has six, didn't yet read what the biggest one does
<whitequark>
from the photo
<DocScrutinizer05>
wait, isn't that a 4 channel scope?
<whitequark>
ah, it's "general purpose knob"
<whitequark>
it's "2+2"
<whitequark>
it has two proper channels and two channels with 10V limit
<DocScrutinizer05>
hm?
<DocScrutinizer05>
you mean no amp?
<whitequark>
you can't set more than 10V/div scale
<DocScrutinizer05>
less
<whitequark>
more
<DocScrutinizer05>
o.O
<whitequark>
HFour-channel acquisition—the TDS 540 offers four full-featured channels;
<whitequark>
the TDS 520 offers two full-featured channels and two channels with
<whitequark>
limited vertical scale selections: 100 mV, 1 V, and 10 V.
<DocScrutinizer05>
what do you want? 100V/div?
<whitequark>
I dunno, I just quote manual
<DocScrutinizer05>
missing 1 and 10 mV/div
<whitequark>
ooh
<whitequark>
yes you're right :)
<DocScrutinizer05>
so, no proper amp
<DocScrutinizer05>
nevertheless you need a knob for each of the 4 chan, to adjust that
<DocScrutinizer05>
or you mess with multifunction dial
<DocScrutinizer05>
you need 4 dials for position of each "beam" as well
<DocScrutinizer05>
so we are at 8
<whitequark>
yeah, it has one multifunction set of buttons&knobs for all channels
<whitequark>
I dunno, isn't 16 knobs a bit excessive?
<DocScrutinizer05>
analog scopes have like 3 dials per channel
<DocScrutinizer05>
plus a few switches
<DocScrutinizer05>
and then they have timebase, that also has 2 dials
<DocScrutinizer05>
and trigger, another dial
<DocScrutinizer05>
plus switches
<DocScrutinizer05>
that's why I say "the dso has too few dials"
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<DocScrutinizer05>
counting, that's actually 16. But we also have brightness and such stuff
<whitequark>
I'm 100% fine with having less redundant elements though
<whitequark>
it's probably a matter of habit
<whitequark>
I mean, I already used DSO so I know how that feels
<DocScrutinizer05>
redundant?
<DocScrutinizer05>
it's just "normalized"
<DocScrutinizer05>
one function one dial
<DocScrutinizer05>
of course you can as well design stuff like: 16 pushbuttons to select function of the one multifunction dial
<DocScrutinizer05>
but then you have two actions per adjustment
<whitequark>
normalized, yes
<whitequark>
well, no. you only have extra actions when switching channels
<wpwrak>
i'd look for a rigol. they tend to have a lot more power for the money. tek are more "solid" but you spend a lot of money before you get something that can compare to a entry- to mid-level rigol
<wpwrak>
btw, the tds520c should be 2 channels, not 4. that would be tds540c
<DocScrutinizer05>
and you can replace the 16 pushbuttons by a few less and have 3 actions for some adjustments
<whitequark>
it's 2+2 channels
<whitequark>
wpwrak: and it sells for $700, you think $700 rigol would be that good?
<DocScrutinizer05>
for 700 bucks you can't go wrong, unless the thing is totally fubar
<DocScrutinizer05>
and when you don't hurry, it will be sold (and on its way to Germany ;-P)
<wpwrak>
yah, that sort of critter has a refurbished list price in the USD 1k - 5k region. so 700 is very good.
<whitequark>
hehe
* DocScrutinizer05
wonders what the "hack your tek" scene looks like
<wpwrak>
i wouldn't worry about the number of knobs. what's annoying is if you only have one set of vertical control knobs and need to select the channel they control with a button. but besides that, there's little that can go wrong
<DocScrutinizer05>
wpwrak: that's exactly what I talk about
<whitequark>
yea, it works like that
<DocScrutinizer05>
you need sensitivity and pos for each chan
<wpwrak>
one issue is that is has no usable data interface. so you'll be taking screenshots with a camera
<DocScrutinizer05>
and it annoys hell outa me to select chan I want to adjust
<DocScrutinizer05>
by pushbutton
<whitequark>
woakas1: floppy?
<whitequark>
there's option 13 for about $60, RS232C
<wpwrak>
ah yes, indeed. yeah, that's messy. you can live with it, though. my rigol has that too.
<wpwrak>
(13) you'll want that :)
<wpwrak>
(floppy) i wrote "usable" ;-) there's also GPIB, but ...
<whitequark>
GPIB costs $300
<DocScrutinizer05>
forget GPIB
<whitequark>
well, the converter
<roh>
modern tek have ethernet
<whitequark>
modern tek also have pricetag :S
<wpwrak>
the old-modern conversion is easy: add a zero and you're there ;-)
<DocScrutinizer05>
hehe
<whitequark>
heh
<wpwrak>
that's why i like the rigols (for new devices). lots of memory, modern interfaces, overall decent performance (they're basically agilents), and their latest models even have a bunch of options you can enable by hacking a code :)
<wpwrak>
i wonder why that tek has a numeric keypad. rather unusual.
<whitequark>
DS1052E: $560
<whitequark>
eh, 1102E rather
<wpwrak>
monochrome screen can be a bit confusing when waveforms overlap. but then the resolution is good.
<whitequark>
1052E is $420
<wpwrak>
naw, 1102E is obsolete. 1xx4Z is the new shooting star
<whitequark>
1074Z: $639
<wpwrak>
24 MSa memory, you can get the 70 MHz and "unlock" 100 MHz
<whitequark>
yeah, I lose on analog bw, but... to be honest I don't have anything above 100MHz anyway
<wpwrak>
not so nice: multiplexed vertical control. but that's understandable given the screen size and the rest of the device size
<whitequark>
tek has multiplexed vertical control too
<wpwrak>
next would be the rigol DS2000 series. alas, only 2 channels. again, you can get the lowest-end model and "unlock" 200 MHz there
<whitequark>
grmbl, this shit's too complex and I'm practically dropping sleeping
<wpwrak>
and they go up to 56 MSa (also unlockable)
<wpwrak>
their nicest is the 4000 series. even more memory, up to 4 channels, more bandwidth, also many things unlockable (memory, bandwidth, serial decode), but a bit on the pricy side
<wpwrak>
the 4000 are also finally big enough for a full set of controls :)
<wpwrak>
one interesting feature of the rigols, i think already starting at the 1000, is the ability to have multiple captures (sometimes called "segments"). so you set up your memory in, say, 1% segments, and then each time it triggers it fills one such segment, and at the end you'll have collected 100 such waveforms
<wpwrak>
another nice thing modern scopes have are waveform tests: you capture a waveform, add a certain amount of tolerances, then let it run and compare each waveform it sees with that pattern. when there's an excursion, stop or just count it.
<wpwrak>
alas, i also have the "can't import" problem. not just me but neither the company that sells them ...
<whitequark>
well... meaning the only thing tek wins at is raw bandwidth
<whitequark>
meaning I should *not* get tek under any circumstances
<whitequark>
like buying a CPU based just on clock freq :)
<whitequark>
unrelated: that container with persulfate+peroxide burps every several seconds
<wpwrak>
bandwidth is of course nice to have. also for "slow" signals, having many times that bandwidth can be useful, e.g., to examine edges or hunt for glitches
<wpwrak>
"burping acid" that's a new one :)
<whitequark>
well, MSDS for both peroxide and persulfate instruct to not store them in airtight containers
<wpwrak>
just make sure it doesn't get out of its container at night and strangles you in your sleep ;-)
<wpwrak>
if i had to buy a scope today, i'd be torn between the 1000Z series and 2000 (or 2000A, which is an update of the 2000 - not sure what exactly changed)
<whitequark>
but it seems very hard to obtain (exactly 1 vendor on ebay for all UV curing inks) and generally obscure
<whitequark>
hopefully acrylic works, it's easily available
<whitequark>
ooh, found some data indicating acrylic is used in industry
<whitequark>
"direct legend printing" process
<qi-bot>
[commit] Werner Almesberger: atusb/fw/usb/: change a few more uses of ../board.h to board.h (master) http://qi-hw.com/p/ben-wpan/8b08594
<wpwrak>
DocScrutinizer05: oh, and if you want a lot of knobs, they have the 1000B series. alas, very little memory and generally a weaker device. together with the 1000D/E, the previous generation. (ther's also 1000C/CD, which is even older. i have one of these, a 1102CD)
<qi-bot>
[commit] Paul Cercueil: Fix key repeat of analog stick working only on some screens (master) http://qi-hw.com/p/gmenu2x/b087e5c
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<nicksydney>
wpwrak: you talking about RIGOL scope ?
<wpwrak>
yup
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<nicksydney>
wpwrak: are there much difference ?
<nicksydney>
between the 2 models ?
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<wpwrak>
which two ? :)
<DocScrutinizer05>
well, believe it or not, for scopes and synthesizers I can't come up with *any* UI that beats good old turn knob dials (or *maybe* linear pots)
<DocScrutinizer05>
even for mixers I could figure alternatives that might work when well done. Not though for scopes and synthi
<DocScrutinizer05>
(in case you wonder: moog is a synthesizer)
<wpwrak>
here's an idea: get a MIDI knob box, then run you scope on remote control from the PC and provide inputs from the MIDI box
<DocScrutinizer05>
might work but sounds pretty clumsy
<wpwrak>
and yes, having a lot of knobs is always nice. but if you can't have the full array, then there are better and worse solutions
<wpwrak>
also, there are other nuisances than having multiplexed channel controls, like cursor A and B on the same knob (very annoying, much more than the channel controls), some operations that require you to spin a wheel a gazillion times to get where you want to go, etc.
<wpwrak>
for deep memory, you also want somewhat more sophisticated navigation. mark/goto, maybe soft-triggers, etc. not sure how well the rigols are doing in that regard.
<wpwrak>
(navigation) if your scope is really responsive, you can more or less get away with just traditional controls. but then we're talking about agilent 7000 and such.
<DocScrutinizer05>
btw dedicated dials not only serve for proper input, they also give a decent direct output about the particular setting
<apelete>
DocScrutinizer05 wpwrak: seems like my little soldering experiment turned out well:
<DocScrutinizer05>
the old teks had a magnifier turndial coaxial with the sensitivity selector, that had a range of iirc x1 to x10 contiguous, and they had a bright orange light on each channel showing when magnifier been "uncalibrated" (aka not x1)
<apelete>
thanks ! \o/
<DocScrutinizer05>
:-)
<DocScrutinizer05>
same for "zoom" which been the spreader for time base
<DocScrutinizer05>
I the heck prefer a huge bright red lamp over any silly writing on display as only feedback
<apelete>
now I just need to glue the wires inside the case, let them get out through the speaker grill hole, close the case and voilà :-)
<wpwrak>
ah, so you didn't change the time base but just the zoom ? sounds nice. they could actually combine that for stopped/idle waveforms by just having an indicator when selected time base and last captured time base are the same
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<DocScrutinizer05>
OOOOH! you will want to add a set of plugs to separate the wires from the PCB
<wpwrak>
leds are cheap :)
<DocScrutinizer05>
(magnifier) mad useful to compare waveforms on two channels
<DocScrutinizer05>
also the invert for at least one channel
<DocScrutinizer05>
of course you have stuff like "A-B" but that is reducing the information displayed on screen
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<DocScrutinizer05>
I don't just want to see the arithmetic difference between two channels, I also want to see the relation between the difference and the common wave
<DocScrutinizer05>
and even for A-B mode you might want to adjust gain in one channel so it matches amplitude in other channel
<wpwrak>
if it gets really fancy, i just download the waveform to the pc and torture it some more there ;-)
<DocScrutinizer05>
I can't recall if contenporary dso have any such modes and adjusting options
<wpwrak>
they tend to have more features than people usually can discover in a year or so :)
<wpwrak>
i'll let you decide whether it is good or bad ;-)
<DocScrutinizer05>
meh, when I need a PC to work with my scope, I think sth is quite messed up
<DocScrutinizer05>
but that's totally in line with my mantra. You probably can do all the analog tricks on a dso as well, but an analog/multibutton scope is just 5 times as fast to get useful results
<wpwrak>
there we differ :) i want the pc as the universal fallback. e.g., if i need to decode ARM's SWD protocol, i can either hunt for a $$$$$ (not just $$$) scope with a $$$$ protocol decoder option, or just write a little perl script
<DocScrutinizer05>
no arguments aginst that from my side
<nicksydney>
wpwrak: between 1000Z series and 2000
<wpwrak>
and yes, i like responsive scopes. i wish they'd open access to their protocol decoders for triggering, because that's something one can't do from a pc
<DocScrutinizer05>
hehe, right
<wpwrak>
nicksydney: ah, i think the bottom like is this: the 2000(A) is a more rounded, higher-class device. BUT it costs more and maxes out at 2 channels. the 1000Z is more basic but gives you up to 4 channels.
<DocScrutinizer05>
analog scopes are slow, they need some 10s to heat up the CRT. But... DSO might take some minutes to boot ;-P
<DocScrutinizer05>
OOOH, and have you seen that DSO with good X/Y mode?
<wpwrak>
note that, while many scopes reduce the sample rate from X for 1 CH to X/2 for 2 CH (2 CH scopes), and X for one channel from each pair and X/2 for >= 3 channels, the 1000Z actually divides all the way down to X/4 if you use all four channels
<DocScrutinizer05>
prolly not
<DocScrutinizer05>
since that's simply not how DSOs work
<wpwrak>
so you get a fairly slow 250 MSa/s at the end. that's still usable, just rather low
<wpwrak>
DocScrutinizer05: never had much use for X/Y ;-)
<DocScrutinizer05>
pathetic ;-P
<nicksydney>
DS1032Z and DS1062Z
<wpwrak>
through it may look cute to plot data against clock ;-)
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<DocScrutinizer05>
XY in some cases beats 2chan hands down
<wpwrak>
"1032" wow :)
<wpwrak>
DocScrutinizer05: probably not in the digital domain. and that's where i spend most of my time.
<wpwrak>
nicksydney: if you want a good entry-level scope, i'd recommend the 1074Z. in many cases 2 channels are enough but sometimes you really really want more, and it sucks if you just can't have them. (my scope is an MSO. the digital part sucks very badly (broken by design, with all sorts of glitches), but sometimes i'm happy to have even that, because i couldn't see things otherwise)
<DocScrutinizer05>
wpwrak: for your RF stuff you could use XY, but then your bandwidth most definitely will defeat that usecase
<wpwrak>
nicksydney: if you want a more advanced device, it's a tie between 1074Z and the 2000 series. 2000 gives you more bandwidth, which is great. and they have also all the features fully developed (in the 1000Z, some are apparently not as smoothly done as in the 2000). the big drawback of the 2000 is that you can only get it with 2 channels.
<wpwrak>
yeah. where's a good 3 GHz scope when you need one ? ;-)
<wpwrak>
the 1102E is not a bad scope. but the 1074Z is definitely worth the difference. i'd stay away from the 1052E. 50 MHz is too low, and "upgrading" it to 100 MHz, while possible, is messy.
<DocScrutinizer05>
"waveform record and playback" is prolly a whole new class of tool, with the opportunities to use this feature yet to get investigated
<DocScrutinizer05>
DSO made it feasible
<wpwrak>
i think they explain in in eevblog, at least for the 2000
<DocScrutinizer05>
I meant playback literally, via two wires
<wpwrak>
ah ;-))
<wpwrak>
well, there are such setups. some of the rigols can work directly with a signal generator ...
<DocScrutinizer05>
:-o
<wpwrak>
nicksydney: is also has twice or more of everything :-)
<DocScrutinizer05>
dang, again an idea I had - too late
<wpwrak>
nicksydney: tell your wife her old shoes look great, much better than any of the new stuff. then you should be able to stretch the budget a little ;)
<DocScrutinizer05>
hardly ;-P
<DocScrutinizer05>
the opposite strategy might work though
<DocScrutinizer05>
new shoes for her only when new scope for him
<nicksydney>
DocScrutinizer05: i think that's a good strategy :)
<wpwrak>
hmm, i think you'll get him divorced. then he'll be completely broke
<DocScrutinizer05>
the trick is finding a good rationale for that
<nicksydney>
why can't scope be like DVD player where it drops in price as time passes :)
<DocScrutinizer05>
ooh it does
<DocScrutinizer05>
in 1975 DSOs were ... err... $$$$$$$ ?
<DocScrutinizer05>
;-P
<wpwrak>
before mail order, you could have said "let go to far-away place X to pick up that scope. oh, by the way, i've heard there's also a whole mall dedicated to shoes there"
<DocScrutinizer05>
I think in 1975 you had analog storage scopes
<DocScrutinizer05>
which been real crap
<wpwrak>
yes, indeed. something like the 1000Z didn't even exist just a few years ago. and those that came close were more in the ferrari price class ...
<DocScrutinizer05>
compared to what you would've needed and what you would've been able to pay for
<wpwrak>
analog storage sounds a bit like storing people in the transporter coils in star trek ....
<nicksydney>
so in another 2-3 years we will see scope like Rigol in the vicinity of the price of beaglebone black :)
<wpwrak>
usually doens't go well for the red shirts
<wpwrak>
well, you'll see some junk brand sell scopes with similar specifications but lousy build quality
<DocScrutinizer05>
wpwrak: worse, in electron tubes
<DocScrutinizer05>
storage CRT
<wpwrak>
if you look around, you find a bunch of evil critters priced below rigol. they tend to make your life a lot more interesting ...
<wpwrak>
hah :)
<wpwrak>
i think at some point in time they also had some sort of ADC+DAC combos, but still CRT output