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02:00 - 15:0015:00 - 00:00

3:00 PM
@PeterJ hahhaa, yes :)
 
@ScottSeidman, what do you teach / lecture in?
 
@PeterJ Biomedical Engineering. I teach a Physiology course for engineers (that a non-engineer couldn't pass), and co-teach a design sequence in addition to the instrumentation cours
 
@abdullahkahraman Yup, but horrible photo
 
@ScottSeidman Wow, how can you manage to know both about biomedics and electronics?
 
3:07 PM
Ahh, cool, I'll have to get around to uploading my pic soon...
 
@abdullahkahraman You just learn a few key words in each ;)
 
@abdullahkahraman whazzup?
 
Better image, you should tell them to change it with this one, lol
I understood nothing on this page: bme.rochester.edu/people/faculty/bio/?id=75
Not even a word, lol
 
@abdullahkahraman Not much better, but I don't a photographer star material. Vestibular system has been engineering-oriented for decades, because its the air-force pilots who experience the system the most, and they're engineers
 
@ScottSeidman Couple of words now, thanks :)
 
3:13 PM
@ScottSeidman I want a button for homework questions, so we can betray students inform teachers easier.
I had to find my own information too when I was a student.
 
@jippie lol
 
nothing wrong with asking questions, but some students just drop the whole homework on us.
and the worst just scan the exercise from the book and put it up as a question
 
grEEtings all!
 
@abdullahkahraman oh, now I see why you copied me in on that question
 
@jippie Great point jippie. We're constantly changing up methods as info becomes readily available. There's no such thing as a text without freely available instructors versions w/ answered questions. Great discussion, but need to sign off for a meeting. I'll be back
 
3:18 PM
@ScottSeidman enjoy!
 
hEEloooo all! Another long day, so I've been missing. Just got home... and now, I'm off to a party in the next half hour. Are any of you interested in Bollywood movies?
 
@AnindoGhosh, are you streaming us exclusive CAM video?
 
@AnindoGhosh only if there are cute girls in them
 
@PeterJ Nope... and I assure you it's not going to be worth watching.
@jippie Google "Shootout at Wadala", check who the stars are. :-)
 
@AnindoGhosh, OK, not interested then, I prefer your R2D2 impersonations :)
 
3:23 PM
@PeterJ Hahaha
 
@AnindoGhosh I guess the answer is 'nope'
 
@jippie Fair enough :-)
 
3:35 PM
@jippie I am doing what I am learning :)
@rawbrawb @AnindoGhosh hEEy!
 
:-) Hiya @abdullahkahraman
 
It is amazing how cheap 2TB SAMSUNG Portable USB 3.0 hard-disks got nowadays..
ONLY $19.99!
I should say it feels heavy!
 
You should buy couple of them
 
@jippie There are people who go and buy these and come us with complaints, as we are expert witness for a court.
@jippie Yeah, only if that tag was a little shorter lol
 
3:40 PM
these brass rods are expensive
yuou have the actual drive there!?
 
@jippie Yeah, that photo is taken by me :)
And it is 2TB, which is 2TeraBrass
 
cool
 
Yo yo yo!
 
@coding_corgi y0y0y0
 
did you try to connect it to your pc or is that not allowed with expert witness stuff
hi @coding_corgi
 
3:44 PM
@jippie I have, they have implemented a USB Mass Storage for the device and that is all :)
 
@abdullahkahraman Shoot! Gimme a second...
Yo yo yo ©
 
@abdullahkahraman looks like an arduino
 
@jippie Yo!
 
@abdullahkahraman I bet @coding_corgi could make the software for it
 
@jippie Hahaha! That is a PCB of a USB flash drive with corrupted flash IC.
 
3:45 PM
@jippie Did you make an Arduino Shield for a programmer?
 
no, I just use a standard test shield
 
@jippie Actually I currently don't have anything going on (meaning I have no life), so sure!
@jippie Like?
 
don't know what name it goes by
some come with screw terminals, some come with a small breadboard
...
 
@jippie I would be shocked if you used an Arduino
 
3:47 PM
@jippie Something like this:
And then put a ZIP socket or something on it, etc.
Sort've like this:
 
@coding_corgi this is mine at the moment
 
@jippie ?
 
@coding_corgi, I'm heading off but now you've left disturbing images of unpopulated breadboards in my head, how can I sleep now???
 
the yellow breadboard is something esle. The blue USB cable is something else too
 
3:52 PM
@jippie Cool!
 
@coding_corgi nice one
 
@PeterJ You don't.
 
where did you find the one with the zif socket?
 
@jippie They sell that at a nearby Geek Heaven (otherwise known as a computer store) but I haven't gotten one yet.
 
@jippie Those cables that goes to the yellow breadboard are matched for 20MHz, right? Oh, there is no need for that, yellow is a color that also have a property to be an signal-integrity fixer :)
 
3:54 PM
Mind you that different AVR's have different pinout. Most are identical but several are very different. Watch out with statically wiring up.
@abdullahkahraman Everything below 1GHz acts as DC
 
@jippie lol :D
 
1GHz has a 30cm wavelength; 100MHz => 3 meters; 20MHz => 15m.
I think the wiring is fine for a little test
 
@jippie I don't really want to deal with jumper wires, so I am looking in to that now,
 
@jippie Yeah, I was joking, lol :)
I know nothing about high freq. :(
 
@jippie I want to put my AVR in, program it, take it out, done! No jumper wires, those drive me crazy!
@jippie Should I make a different shield for each AVR or....
 
3:57 PM
I have to go!
See you all!
 
@coding_corgi I'd personally put a row of sockets along side the ZIF socket, so I can push in short, made to fit, jumper wires. Then if I have to program a different AVR pinout I can change the jumper wires/
 
Hey guys I have a question for y'all
Let's say I want to spy on some high speed UART lines which are going between two MCUs
so I add a little connector between the two MCUs that allows me to tap into them
but now let's say I'm worried about my additional trace length and connector adding some ohms and some farads to the trace and affecting it's rise time etc.
What is the name of the IC that I would put on there to clean it up?
high speed buffer or something?
 
use a fet or opamp as probe
 
@jippie ok...
 
eh, i could do that... but let's say I dont want to =P
Aren't like octal buffers designed for this?
?
 
4:03 PM
@jippie Here is my current setup:
 
@NickHalden bit.ly/14kifRw
lol
I'm out, bye guys!
 
@abdullahkahraman Thanks... but not at all what I'm asking
 
Hi all
 
@NickHalden I know, I wanted to make you mad :)
@DavidKessner Hi, and bye!
 
4:07 PM
@DavidKessner hey! you'll know the answer to my question =) See the last 30 lines of chat or so
 
@NickHalden @DavidKessner, don't!
lol
 
@abdullahkahraman Was it something I said?!?!?! :)
@NickHalden What is the signaling standard being used? LVTTL? RS-232?
 
@DavidKessner uhmmmm normal TTL
well actually
it's 0 - 3.3V
so yeah LVTTL i guess, or is that only for 0-1.8V?
let's called it MVTTL haha
 
@NickHalden LVTTL is generally used for 3.3v TTL, although it is a bit misleading.
@NickHalden Bit rate?
 
to spy on them i added a connector which i just connect to an FTDI cable and then look at it on my computer
@DavidKessner currently we're operating on either 57600 or 115200
and there's never been an issue
but for the sake of the question, let's pretend we wanted to go higher to where it would become an issue
 
4:20 PM
@NickHalden Let's start with the practical side of things first. 115.2kbps is not high speed, and it is unlikely that you will need to do anything special. The added trace/wire length is unlikely to do much. The worst thing would probably be huge overshoot/undershoot that actually causes the chips to latch up and literally destroy themselves.
 
@DavidKessner right, that's why i said for the sake of the question assume we want to go higher
 
But let's say that you wanted to go faster... Then you would use a buffer or two of some sort and insert them into the line. But the thing about buffers is that there are so many to choose from. The exact one is hard to say, since it depends on the cable lengths, the data rates, etc. Some buffers are better at driving long lines than others.
 
@DavidKessner we're talking like a few cms here
@DavidKessner so the part that i linked to is at least reasonable... headed in the right direction?
 
@NickHalden Yeah, buffers are huge overkill for this application.
 
@DavidKessner Agreed, was just thinking/curious
@DavidKessner i used a memory chip with an SPI clock of 4MHz once and it was very sensitive to added capacitance from putting stuff on a breadboard so that's why i was wondering.
 
user61389
4:31 PM
@abdullahkahraman thanks, it went well :)
 
@NickHalden I wouldn't use a 74HC part, but it would work. Just about any buffer would work at <1mbps and several cm.
 
user61389
@PeterJ sorry, I a now :D can I still be of any help?
 
@NickHalden Odds are that it was sensitive because you didn't have proper trace impedance and proper signal termination. Not because of the capacitance.
 
@jippie Do you thing ARM is a good micro-controller to use after AVR gets boring (although I am far from that)?
 
@coding_corgi Absolutely! My 8th grader son used an ARM M3 in his science project!
 
4:37 PM
@DavidKessner Cool!
@DavidKessner What did he do?
 
@DavidKessner well the breadboard capacitance affected the trace impedance no? after soldering it onto perfboard it worked perfectly without the buffers in place so i assume it was from the breadboard...
 
he made it explode
 
@jippie !
 
@coding_corgi A "drop tower" amusement park ride. The ARM controls the stepper motor to raise thing up the tower.
 
@coding_corgi yep. that is the perfect transition. that said you have YEARS before you've exhausted AVRs
 
4:39 PM
ARM is quite bit more complex, but there are tools
 
@DavidKessner Cool!
 
@coding_corgi there are many tiers of AVRs, so once you get tired with the ATmega328 or w/e you're using now, look at the xmega line, and then even the AVR32 line. THEN move to ARMs
im currently starting to feel comfortable with xmegas and am shortly going to move to AVR32s before jumping into ARM
 
@DavidKessner what is wrong with two push buttons and some manual labour at that age?
 
so i know how the journey works
 
@NickHalden It is impossible to say without looking at it on an o-scope. But capacitance, impedance, and termination all manifestations of the same thing (when you are talking about wires/traces). In fact, on PCB traces the impedance is directly related to capacitance.
 
4:40 PM
@NickHalden What's so special about XMega?
 
@jippie We also 3-D printed a lot of the parts. He is getting good at Solidworks.
@jippie Part of the assignment said, "minimal human interaction".
 
@DavidKessner right, ok well thanks for he info. So to sum up, a buffer similar to the one i linked would be what im looking for if this problem were to occur.
 
@NickHalden Yes.
 
@coding_corgi they're just more feature rich than normal megas and therefore allow you to do more complex stuff and encounter more complex bugs and learn more complex things
 
@NickHalden Like?
 
4:43 PM
@coding_corgi like full speed USB, or a full 802.15.4 networking stack
have fun implementing that on an mega168
 
@NickHalden Cool!
@NickHalden What are Atmel products used in? I just want to know if I am wasting my time...
 
cars
 
@coding_corgi haha no, they're probably in the top 3 for most popular low end microcontrollers. definitely not wasting your time learning AVRs. Especially since 95% of the knowledge will be transferable.
 
i believe bmw is on avr
 
@jippie SWEET!
@NickHalden What's the other 2?
 
4:48 PM
@coding_corgi PIC, and then specialized 8051 combo cores would be my guess
not an industry expert here, but those would be my guess for top 3
 
Just because seeing the modern manufacturing processing: is just to be the cheapest, and not all AVRs are so cheap...
@NickHalden Doesn't Apple have some Atmel products in it?
 
@coding_corgi no idea. i stay far away from apple products
 
@NickHalden What?! You haven't read Steve Jobs?! It makes you love Apple...
 
it would not, i assure you
 
I think I'm going to postpone my social life with an extra month @AnindoGhosh
 
4:56 PM
@NickHalden Ok...
 
@NickHalden ARM does a fairly good job lately
 
@jippie oh ARM is killing it, but i dont put them in the same low end bin as like 8-bit AVRs and PICs
 
But ARM is definitely more high end than AVR
 
@jippie exactly =P
 
@NickHalden totally different market share, I agree. But both used on Arduino ;o)
 
4:58 PM
@CamilStaps The other day I was about to buy a PIC kit just because it had a battery back in it, but then I found an AVR kit with the same stuff and more, if I got the PIC kit I would've smash the tiny little PIC with a hammer, and post the picture on EE chat...
 
user61389
@coding_corgi I need more powers.
 
Arduino fills plugs the gap between AVR and ARM :o)
 
@CamilStaps Powers like?
 
user61389
@coding_corgi burn messages
 
ok im out for a bit
ttyl guys
 
5:00 PM
@CamilStaps Messages like?
 
@coding_corgi powers like not loosing reality
 
user61389
@coding_corgi anti-PIC
 
@CamilStaps Messages like crushed PICs?
 
user61389
@coding_corgi might be
 
@CamilStaps Hmmm...
 
5:12 PM
@CamilStaps take a look:
DA END OF PIC!
@CamilStaps It's actually kind've scary...
 
user61389
With 'that silly 8 bit microcontroller' I can do a better filming job than this.
 
@CamilStaps Anyone could...
@CamilStaps Though please make a video of you destroying PIC microcontroller...
 
user61389
5:30 PM
@coding_corgi wasn't planning, sorry
 
@CamilStaps ..... ARGHHHHHH!
 
5:46 PM
I think filming in a fire is a bit more difficult than you would expect.
 
@jippie Just a little...
 
6:30 PM
The "Explain in Detail why" indicates this is homework of some sort that has been transcribed onto this site without showing the effort to arrive at an answer, if one exists at all. Voting to close, sorry. — Anindo Ghosh 3 hours ago
@AnindoGhosh don't give away our methods to figure out homework questions ;o)
 
6:41 PM
 
@ThePhoton Cool...
 
I want the print
Also, be sure to read the mouse-over.
 
7:27 PM
@MLM Yo!
 
MLM
@coding_corgi Hey
 
user61389
7:58 PM
Do we really need an tag?
 
@CamilStaps YES! :)
 
@CamilStaps Yeah, it seems odd
 
@CamilStaps no...
 
user61389
@W5VO thank you - I thought, perhaps regarding the discussion about the difference between EE and electronics it might be useful to people who distinguish that difference
 
@CamilStaps It's about as useful as
 
user61389
8:14 PM
Lol :)
 
8:28 PM
Notice the transistors. Am I correct by using P-channel symbols when I port the top schematic to circuitlab for better readability?
 
8:53 PM
@jippie The upper schematic has n-channel fets.
 
@ThePhoton thought so, the arrow in the symbol is the other way around, right?
 
The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a transistor used for amplifying or switching electronic signals. Although the MOSFET is a four-terminal device with source (S), gate (G), drain (D), and body (B) terminals, the body (or substrate) of the MOSFET often is connected to the source terminal, making it a three-terminal device like other field-effect transistors. Because these two terminals are normally connected to each other (short-circuited) internally, only three terminals appear in electrical diagrams. The MOSFET is by far the ...
 
ah no bulk
 
@jippie yes, the arrow is opposite if you draw it in the source leg from if you draw it in the body connection.
 
figures
i guess
thnx
 
8:55 PM
@jippie Of course you are in Europe so you can probably find a standard that contradicts me.
 
@ThePhoton I use the 'dot' for PFETs - I get fewer questions that way :)
 
wikipedia is in black an white, that counts as absolute proof
 
@W5VO Haha, I thought that was the symbol digital guys use. (Cue Widlar poster)
 
@ThePhoton Is it just me, or is a match fairly weird to use as a scale reference in that wikipedia reference
 
@W5VO If I want to start a fire, I'll overheat my FETs myself, thank you very much.
 
8:57 PM
@ThePhoton It is - but I like it so much more than arrows and random body connections
 
@W5VO I'd repost the Widlar poster, but I see you were the last one to post it here.
 
and if it's on die, the source is relative :)
@ThePhoton Digital is for those who failed transistor biasing in college :)
 
Does anyone know a good guide on how to reverse engineer an electronic device?
I've extracted a WiFi module from a wireless printer.
I've found a bit of information but no datasheets.
 
1
Q: MOSFET symbol - what is the correct symbol

Andy akaI've been on this site now a couple of months and I notice various symbols used for MOSFETs. What is the preferred symbol for an N Channel MOSFET and why?

I'll leave the honours to you :o)
 
I'm almost positive that it's a USB device of some sort. It has five wires. Four of them together and one separate that was connected to the metal casing.
Also, this page has some limited information: wikidevi.com/wiki/Foxconn_T77H054
Problem is, all five wires are blue. So I have no clue what's positive, negative or data.
 
9:09 PM
@William'MindWorX'Mariager Don't know. USB has +5V and 0V (GND), those should be pretty easy to figure out.
@William'MindWorX'Mariager the wire to metal casing is shielding.
 
@jippie Yeah, that's what I assume as well.
 
shield to ground resistance will be very low
and the other two .. don't know how to uniquely identify them
time for bed
/me is out.
 
Alright, thanks. That'll sort out three of them.
Assuming they're somewhat correctly ordered, I should have VCC and GND on opposite sides.
 
@jippie Hi.
 
@William'MindWorX'Mariager probably D+ and D- are twisted for data integrity
 
9:13 PM
Well, it isn't an actual USB cable leading to the device.
 
Power supply rails should be pretty easy to identify on most any PCB
or look in the device where you found it.
@William'MindWorX'Mariager interesting antenna design
anyways
/me is out
clickk
 
10:13 PM
@William'MindWorX'Mariager There is reverseengineering.stackexchange.com
 
still grading exams
 
11:17 PM
@ThePhoton that question still there, awaiting your brilliance, I've sweetened it.
 
11:46 PM
Yo yo yo!
 
11:58 PM
@coding_corgi Are you walking on the moon? (elyrics.net/read/p/police-lyrics/…)
Sorry no YouTube video---blocked from work.
 
02:00 - 15:0015:00 - 00:00

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