<azonenberg>
monochroma: also MEAD boards being assembled tonight. Jes is on the mill right now milling out the MMCX slots so the connectors actually fit
<azonenberg>
a 1.45mm carbide endmill works great on fr408, and it looks like we only have to take off 50 μm from each side of the slot to make it fit
<monochroma>
azonenberg: oh yeah, did you have any photos of what the issue there was?
<azonenberg>
the issue is pretty simple, the connector slips into a U-shaped slot on the edge of the board
<azonenberg>
the slot is about 75 μm skinnier than it should be
<azonenberg>
so the connector won't fot
<azonenberg>
fit*
<azonenberg>
i think it's cutter compensation mismatch on my end vs oshpark's
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<azonenberg>
Sooo
<azonenberg>
the Murata DC-DC module i put on the MEAD+INTEGRALSTICK board - same one i'm using like four of on MAXWELL - is bigger than it looks
<azonenberg>
it baaaarely fits on that board
<azonenberg>
almost knocks a resistor off
<azonenberg>
Aaaand that board is reworked and ready to go. Put the BLONDEL testbed away for a little bit to free up bench space
<azonenberg>
Top side of the MMCX-to-MEAD board is assembled, bottom side is pending arrival of the LSHM connector
<azonenberg>
MEAD board itself is also pending arrival of the LSHM
<azonenberg>
Which should be arriving around the same time as the sfp-to-sma
<azonenberg>
The MEAD+INTEGRALSTICK board looks good. after some fighting to align the tiny WLCSP power switch (not going to be using that on MAXWELL) i got it in place
<azonenberg>
and the SFF connector fits properly and everything looks good there
<azonenberg>
so I think that's about all i can do on the assembly/test side until the LSHMs or the SFP-to-SMA boards come in
<azonenberg>
Still need to do lots of MAXWELL design review
<azonenberg>
oh and then the v0.9 probe is in but i didnt have time to assemble today
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<katharina>
azonenberg: Will we need enums as preference values in the near future? E.g. something like how much metadata to emit to the session file etc
<bvernoux>
I think this one will be the good one ;)
<bvernoux>
using 0402 parts too
<bvernoux>
OSHPark will sponsorize me also to produce it with OSHPark 4 Layers
<bvernoux>
as such board is quite expensive with 4 Layers @OSHPark > 100USD for 3 boards
<bvernoux>
There is special silkscreen around pin to easily solder it with other connector ;)
<bvernoux>
That shall not impact performance a lot as it is very thin
<bvernoux>
I can always remove this silkscreen too in worst case ;)
<bvernoux>
I will compile all my tests results with different SMA connectors to show how that impact RF
<bvernoux>
it is clear that cheap SMA connector have huge impact ;)
<bvernoux>
so far the best is BELFUSE 142-0771-831 I need to figure out what is the issue with SouthWest Microwave connectors as they shall be even better in theory
<azonenberg>
Have you tried the amphenol one i like?
<bvernoux>
no
<azonenberg>
They look almost identical
<bvernoux>
It seems very similar to BELFUSE 142-0771-831
<bvernoux>
will be interesting to compare them ;)
<bvernoux>
anyway BELFUSE 142-0771-831 price is clearly winner so far
<bvernoux>
when bought directly from Powell Inc
<bvernoux>
410USD (without VAT / Shipping) for 100 connector is nice ;)
<bvernoux>
clearly a very good deal except they are pretty hard to solder so far
<bvernoux>
maybe I will try the variant with legs (PCB hole) to easily align it
<bvernoux>
As long as the bin is never opened during the soldering process, the consumption will not be more than about 0.5L per 100 prints
<Degi>
I mean you could even use water
<bvernoux>
So I suspect it is the same with Vapor One
<bvernoux>
it is wrote
<bvernoux>
Volume of Galden used per cycle: 0.49 ml (about $0.16)
<bvernoux>
So not so expensive but the HW is expensive anyway
<Degi>
I mean you could just compress water to 4 MPa and do soldering haha
<Degi>
Or ethylene glycol at 0.3 MPa
<bvernoux>
I doubt water is good for soldering even at high pressure ;)
<Degi>
I mean water has very good heat transfer
<Degi>
Like 2 kJ/g
<Degi>
(for 100 °C)
<bvernoux>
but for corrosion ...
<Degi>
hmh yes thats a downside
<bvernoux>
Galden has not that effect
<bvernoux>
so it is not simple water boiling at 240°C ;)
<Degi>
O.o
<Degi>
What if you use glycerol at 200 mBar
<Degi>
Thats very doable
<Degi>
And its friggin cheap
<Degi>
Hmm it might dissolve certain plastics
<Degi>
Does Galden need to be washed off at the end?
<Degi>
Though that would need active heater control
<Degi>
Basically 1) vacuum out chamber, 2) heat glycerol until 200 mBar reached 3) cool down and wash
<sorear>
i suspect glycerol is also pretty corrosive with the reactive -OH
<sorear>
OTOH aliphatic alcohols are significantly less acidic than water
<Degi>
Hmh#
<sorear>
glycerol will definitely corrode, say, sodium at room temperature, no idea if it attacks copper at 240C
<Degi>
Huh
<Degi>
I mean probably not very much? idk
<sorear>
on the other other hand, chelate effect
<Degi>
Does that also cause corrosion
<sorear>
probably, since it favors the ionic phase
<Degi>
Hmh copper?
<sorear>
chloride or cyanide would complex pretty strongly
<Degi>
I mean even pure HCl doesnt etch copper
<Degi>
Well it needs an oxidant like oxygen from air
<bvernoux>
Degi, Galden does not need to be washed or anything at end
<bvernoux>
Degi, it is the magic ;)
<Degi>
Hmh where does it go
<bvernoux>
it go back like awter
<bvernoux>
water
<bvernoux>
when refreshing
<bvernoux>
there is a video about it
<bvernoux>
what is lost is some micro wavelet of galden IIRC
<bvernoux>
also it seems safe for human if you eat it ;)
<Degi>
Biphenyl has a good boiling point
<electronic_eel>
azonenberg: do the UARTs to the pods on MAXWELL have EDS protection?
<electronic_eel>
I didn't see any, but I still have a strong feeling of being overwhelmed by the complexity...
<azonenberg>
electronic_eel: they do not, good catch
<azonenberg>
ESD protection is quite a few lines down on the review checklist so i havent got there yet
<electronic_eel>
also I'd add some 33 ohms series resistors, just for good measure. maybe use some resistor packs for it
<electronic_eel>
the *_present signals also don't have ESD protection
<azonenberg>
Noted
<electronic_eel>
what are the 300 ohms resistors between the pod power and the pods for?
<azonenberg>
those aren't resistors
<azonenberg>
those are 300 ohm @ 100 MHz ferrite chis
<azonenberg>
chips*
<electronic_eel>
ah! yeah, FBnn
<azonenberg>
To minimize radiated emissions on the pod cables
<azonenberg>
I'm trying to actually put some effort into EMC on this thing
<electronic_eel>
300 ohms wouldn't have worked well with the pods...
<electronic_eel>
I'm confused by all the different I2C busses and them constantly changing their name from sheet to sheet
<electronic_eel>
you need that many, no doubt about that
<electronic_eel>
but wouldn't it help to keep their names constant across the sheets, so you can follow them better and better tell them apart?
<electronic_eel>
that will also give them consistent names in the layout file
<azonenberg>
i did this via a bottom-up design and some net names were assigned in sub-sheets then, for example, two different sheets' buses got put on the same physical bus
<azonenberg>
and renaming dozens of net connections in the sub sheets seemed error prone
<azonenberg>
the final net names are hierarchically scoped
<electronic_eel>
can't you do a simple rename, just with search & replace? I don't consider that error prone
<electronic_eel>
giving the same thing 3 different names on different sheets seems more error prone to me
<electronic_eel>
where are the pullups for the probe and power / ram i2c busses?
<_whitenotifier-f>
[starshipraider] azonenberg pushed 1 commit to master [+0/-0/±6] https://git.io/JfhsA
<_whitenotifier-f>
[starshipraider] azonenberg e9def1e - Continued schematic review
<azonenberg>
electronic_eel: very possible they're missing, checking for missing pullups is a few steps down on the review
<azonenberg>
i'll add a note to look
<electronic_eel>
searching for stuff like that would be easier if the bus names were consistent
<azonenberg>
yeah let me see what i can do on that
<_whitenotifier-f>
[starshipraider] azonenberg pushed 1 commit to master [+0/-0/±10] https://git.io/JfhG8
<azonenberg>
Updated, new PDF uploaded
<_whitenotifier-f>
[starshipraider] azonenberg 70188ab - Renamed I2C buses to be consistent
<electronic_eel>
much better, thanks
<electronic_eel>
my kicad always takes about 5 seconds to load the schematics
<electronic_eel>
never had a schematics this complex before...
<electronic_eel>
the supercap for timekeeping is something that will age. but seiko doesn't want to tell in what kind of timeframe (ds: "long life span, high reliability")
<electronic_eel>
it is a quite small smd package, I don't know if the user can be expected to change it in 10 years (or when the thing will fail)
<Degi>
Maybe mark it on the PCB haha
<Degi>
"Place a 3.3 V supercapacitor here of some dozen mF if timekeeping fails or fluids leak out"
<electronic_eel>
on the other hand it is nice that it is so mall
<electronic_eel>
I don't know how it will fail, just no capacity left, or will it have a huge leakage current?
<Degi>
Maybe itll have leakage fluid
<electronic_eel>
if it is just the capacity that goes down, we could add a pin header and the user could plug in another cap
<sorear>
why does it have a RTC?
<Degi>
Good question
<electronic_eel>
to tag the samples with a rough time
<Degi>
Cant it do ntp
<electronic_eel>
for more precise timing ntp, ptp and gps is planned
<Degi>
Or will the time need to be entered at the front panel
<electronic_eel>
that wouldn't be nice ux. you'd probably set it from the host instead
<electronic_eel>
there is a safety datasheet on digikey. "solute: Tetra alkyl ammonium salt, solvent: hetero-oxide"
<electronic_eel>
don't know what that is, but it sounds a bit to me like it could leak
<Degi>
We could use lithium thionyl chloride batteries
<electronic_eel>
given enough time
<Degi>
The oxide could be a solid maybe
<electronic_eel>
I had good experience with the regular CR2032, they are cheap and easy to replace and work well for >5 years with a simple RTC
<electronic_eel>
only downside is that they take a lot of space
<Degi>
yes
<electronic_eel>
but I've seen some mainboard manufacturers plugging them in with a small jst connector and sticking them someplace on the pcb with double sided tape
<electronic_eel>
the battery is shrink wrapped and the cable welded on
<Degi>
ah these
<electronic_eel>
I guess you can buy them that way, so you just need the connector on the pcb
<azonenberg>
yeah i dont plan to use the bbram for settings or other critical stuff
<Degi>
Huh 2.5 MJ/kg
<azonenberg>
the battery is just to persist time across short shutdown cycles
<azonenberg>
without hammering the ntp server
<electronic_eel>
but if it begins to leak after a few years...
<azonenberg>
we might even end up DNPing on the final build and just having the diode+cap to supply vbat when it's on
<electronic_eel>
I'm not very convinced by the ""long life span, high reliability" language in their ds, no actual numbers anywhere, that sounds fishy to me
<Degi>
Shorting out thionyl chloride ones sounds fun
<electronic_eel>
how about replacing it with a molex kk connector for plugging in a lithium battery like the ones degi linked?
<azonenberg>
i think it makes more sense to keep it as designed, but with the assumption of DNPing down the road?
<azonenberg>
i really dont even think it will be used at all
<electronic_eel>
azonenberg: hmm, why do you have it in there, then?
<azonenberg>
Because a DNP is less work than bodgewires :p
<azonenberg>
same reason i hooked up the RMII between the FPGA and STM32
<azonenberg>
I have no immediate plans to use it, but it might be needed in the future
<electronic_eel>
yeah, but it might come in handy to have for some feature or workaround that we do not know about now
<electronic_eel>
but I think having a battery then, which can be user replaced, is better than having a leaking supercap
<Degi>
Why does digikey have several hundred kiloampere-hours of LiSOCl2 batteries on storage
<azonenberg>
electronic_eel: batteries can leak too, and this thing is easy to rework if needed
<azonenberg>
its also a hermetically sealed ceramic+metal package like a crystal oscillator
<electronic_eel>
Degi: the person responsible for fire hazard precautions at Digikey wants something to do
<azonenberg>
i doubt it would leak
<azonenberg>
fail, perhaps, but not leak
<Degi>
Thats like a few dozen kg of lithium haha
<electronic_eel>
Degi: extinguish the fire with water
<Degi>
big boom
<electronic_eel>
azonenberg: I'd prefer the pin header solution, I think it is more flexible for something that you don't know the exact usecase for
<azonenberg>
electronic_eel: ok fine... does it have to be a KK or can i just put down two 100 mil spaced pins and we'll go from there?
<Degi>
That should be fine if you mark polarity on silkscreen
<azonenberg>
Ok
<azonenberg>
So then the user can populate the cap+diode, battery, or any combination thereof
<electronic_eel>
just the 2.54mm pin headers, you can solder in kk's or anything similar later on
<azonenberg>
will also double as a test point for the cap
<_whitenotifier-f>
[starshipraider] azonenberg pushed 2 commits to master [+1/-0/±2] https://git.io/JfhZ2
<_whitenotifier-f>
[starshipraider] azonenberg 102212d - Added 2 pin header to VBAT rail for optional external battery
<_whitenotifier-f>
[starshipraider] azonenberg 115c913 - Added autosave to gitignore
<electronic_eel>
ok, enough review for me tonight, will go to bed now
<Degi>
Huh, CNC devices for 200 €
<electronic_eel>
hrmpf, can't shut off my brain from review mode this fast, I keep thinking about the schematics and still find stuff, even with no pc on
<Degi>
Heh yees
<electronic_eel>
I suggest to add polyfuses to the fan headers. a fan could be blocked or otherwise damaged and create a short on the 12v0
<azonenberg>
electronic_eel: They have PWM and tachos
<azonenberg>
if the tach shows no motion i'll stop sending PWM
<azonenberg>
i guess a polyfuse wouldnt hurt on top of that
<electronic_eel>
yes, but that won't help if the fan bldc driver is burnt
<azonenberg>
that *is* a pretty high current rail
<electronic_eel>
I had that on a pc at a customers site, the wire to the fan burnt the isolation
<azonenberg>
500 mA sound like a good polyfuse rating?
<electronic_eel>
that is fine, the fan should never draw that much
<azonenberg>
Exactly my thought, the one in my cart is rated for 170
<azonenberg>
so thats a comfortable margin
<electronic_eel>
ok, now I try again to get some sleep
<azonenberg>
507-1799-1-ND?
<azonenberg>
500 mA trip, 250 mA hold
<electronic_eel>
yeah, that should work fine. I use some bel fuse polyfuses too and they worked well
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<_whitenotifier-f>
[starshipraider] azonenberg pushed 1 commit to master [+0/-0/±4] https://git.io/Jfhnu
<_whitenotifier-f>
[starshipraider] azonenberg 1e78cf7 - Added polyfuses on 12V0 rails for fans
<Degi>
Huh, fans dont have current limiting?
<azonenberg>
Degi: dumber fans as opposed to BLDC ones are literally just a dc brushed motor hooked up to the 12v rail