Electrical Engineering

angelatlarge

1:34 AM

@Kortuk ping

Kortuk

@vicatcu no, you should be able to have a much more complicated circuit that uses FETs and only has a ~.4V drop when on

@angelatlarge Hello

angelatlarge

@Kortuk Is "bleeper" a device that goes off when you say a bad word?

0

Q: Desperately need help with a drink mixer

I am working on making a drink mixer inspired by BAR2D2, I am using a gravity fed pump that is capable of running on a 9v battery. I am using a circuit with a 555 timer to control how long the pump will run. When I hook the pump directly to the battery the pump runs perfect. When I plug it onto m...

Kortuk

thefreedictionary.com/bleeper

@angelatlarge :)

angelatlarge

@Kortuk Holy smokes, it is a real word!

Kortuk

@angelatlarge "real" I can find lots of things on google. But yes, it seems this one is.

Now for my oddity for the night.

►

angelatlarge

1:41 AM

WTF?

Kortuk

exactly

angelatlarge

@Kortuk Is that what you do when Mr. T. lies low?

Kortuk

@angelatlarge haha

I have actually been working on the RPI

angelatlarge

Rensselaer Polytechnic Institute?

hhh

Btw have you seen this https://getmyo.com/?

I have wondered how this kind of bionic things work. Is it due to stretching where it affects electrical properties somehow? Or is it more nuached such as EIT (electrical impedance tomography) where you measure the voltage on the border?

Have you seen this pitch? It is a Y-combinator backed so should not be faked.

Kortuk

1:46 AM

@hhh hard for me to know how they are measuring it, must have a nice sensor

hhh

I doubt voltage measurement in the nerves such as ulnar nerve

I think the hard part is not really the sensor but the anatomy, they need to calibrate the measurement first to some nerve or vein (with different people, it is somewhat different)

The vein could arteria interrossea communis where the more oxygen-loaded blood creates a field to measure but this is slow. So it is a past factor.

The nerve could be the future factor.

While muscle could be a present factor.

Perhaps some sort of PID controller...thinking...

(EIT measurements require just a multimeter...)

the problem is that when you do activity the different factors work differently. If you are doing sport, you get oxygen-loaded blood faster creating different field

(I have no idea whether it is possible to measure the field created by the blood flow)

Kortuk

@hhh It is definitely something that would be very very hard to make easy and reproducible. veins are in different places on different people and such, maybe there is something easy to calibrate to, maybe a calibration motion. I dont know, if it works well I will be very impressed.

@hhh I am not a biological expert.

hhh

I think it does: they got 1.1M funding in Y-combinator already so some proto is already done -- although the video looks a bit fake, too good -- there is some lag unless the guys really know what they are doing...even then it is pretty hard. They need to measure very little things.

(I am no electronics expert XD

...well this is more anatomy, physiology, control theory, physics, math -- a lot of different things jammed together, fascinating :)

Kortuk

@hhh interesting things always are boundary problems.

hhh

Yes it is.

I have consulted different electronics/hw guys about joining this kind of project or cost of doing this kind of thing -- and the cost estimate has ranged from 2k EUR to 2E6 EUR...large differences! Always when people are doing something totally new, it is impossible to estimate the true cots and time etc

Kortuk

2:01 AM

@hhh yeah, 2k EUR is way way low. You generally can not buy equipment for that much:)

hhh

Precisely and you need probably make here pF-accurate measurements or something like it -- it is very-very small amount of voltage that is need to activate a nerve and measuring that voltage through the protective insulator aka skin is impossible or very very hard

Ofc it may be that they are only measuring the expansion of muscle which is far easier task (and this video is only mere marketing).

I wish there was some electromedical publications that covered what is possible and what is not.

Kortuk

@hhh it is possible they have something unique to measure it also, it looks very interesting.

hhh

unique?

Kortuk

@hhh sorry, what is the word.

New.

That is not the right word, but it gets the idea across.

hhh

Methods:

1. EIT = Electrical impedance tomography, measure voltage on the border
2. Muscle expansion, volume
3. oxygen-flow-induced fields: difference btw incoming/outcoming blood flow fields?
4. other?

(this is my thinking, there may be other methods)

Kortuk

2:12 AM

@hhh yeah, Sorry I cant add that much to your list, I dont know what else it might have.

hhh

5. nerve, measuring the extremely small voltage in nerves or its induced field such as ulnar nerve

(all methods have their bad sides and good sides: the truth must be somewhere in the middle or some idea I cannot see now)

.
I wish I could do a prototype where I could measure voltage on a ring over many locations. I can do it with multimeter but I am not sure how I could automate it.

Kortuk

:)

vicatcu

hey guys how's it going?

Kortuk

Would be fun, but for cheaper you could probably buy their product and reverse.

@vicatcu Good, you?

vicatcu

good

Kortuk

2:16 AM

Anyone here have suggestions for SSH client.

hhh

(speculating about methods that may be used in the myo, Y-combinator startup pitches a band proto -- got 1.1M funding...)

vicatcu

@Kortuk command line ssh?

Kortuk

@vicatcu Yes.

Unless it is easy to make a visual one. I know nothing about this at all.

vicatcu

what's wrong with opening a terminal and typing ssh?

are you not on a linux system?

Kortuk

@vicatcu haha.

Awesome response.

I use windows.

hhh

2:19 AM

(cygwin? Putty?)

vicatcu

install cygwin

qed

so i have the simplest circuit i'm struggling to simulate with circuitlab

circuitlab.com/circuit/sbbkhk/voltage-choice-switch

i want to source 3V when 5V is not connected

and source 5V when 5V is connected

Kortuk

@vicatcu is this about to blow my mind?

vicatcu

well i don't want to use a common cathode diode pair

cuz i don't want to drop 300mV for this functionality

but i think i must be doing something wrong

i thought i could use MOSFETs like diodes

to get the same effect, am i wrong?

Kortuk

@vicatcu opening the circuit

vicatcu

k

Kortuk is your mind blown?

Kortuk

2:27 AM

@vicatcu still installing.

angelatlarge

@vicatcu The circuit would be easier on the eyes if the FETs were not rotated...

Kortuk

@vicatcu I know there is a trick to this, and I also know mosfets are my biggest weakness, which is why I think I am useless here.

vicatcu

hehe me too!

Kortuk

@vicatcu I know that if we knew what we were doing we could do this.......

@vicatcu it asked me which packages, i just clicked all, it has been running for a while now

and at 5%

angelatlarge

@Kortuk You never told me what RPI was.

Kortuk

2:33 AM

@angelatlarge Sorry, was being lazy, raspberry pi

I have it, but it does not have resolution settings to go through my vga adapter for me to have two computers here.

angelatlarge

@Kortuk Oh, right, I only get that with capicalization like this: RPi

Kortuk

@angelatlarge Yeah, I randomly capitalize

I am scared I am about to have to use VI to edit a config file for resolution

angelatlarge

@Kortuk For me, it is easier to use cat > somefile than vi somefile

Kortuk

@angelatlarge I am getting linux stomped, as I expected.

hhh

I Found it! It is called Electromyography: mix of different sciences, electronics and practise:

http://en.wikipedia.org/wiki/Electromyography

(no reason to reverse, it is all about silicon and it would cost head-and-legs and be very slow -- far easier to study oneself and find alternative solutions :)

Kortuk

2:37 AM

@hhh There are two sides, sometimes buying a mass released product saves some cost to study it.

@hhh EMG is what they do on your head also, I though. I will have to read more, I have seen people work on these sensors.

hhh

@Kortuk ...yes but it is silicon, I don't have capital to reverse-engineer it...

Kortuk

@hhh Ha, sorry, I did not mean to disagree, just explaining why I suggested it.

hhh

...but developer-edition is probably better option to speed things up -- but then I cannot develop it myself, I think I rather buy a book for 149USD than the device :D

Kortuk

@hhh :)

@hhh one of those things, very very fun to learn about, just have to decide how it is easiest to join in.

hhh

I try to do it in a team but it is dxmn hard find proper people...

which sensors you meant? :P

(I know the Iron Man sensor :D ...but it is a trivial solution)

Kortuk

2:42 AM

@hhh Ohh, I would have to go digging, I have just seen sensors for it before. I thought we had a few questions on site about them, not sure if they are well answered.

vicatcu

hey does anyone know how to embed an existing circuitlab schematic into a question?

Kortuk

@vicatcu quietly.

:)

Carefully.

I dont. :(

vicatcu

haha

Kortuk

@vicatcu why did you not tell me to not install all the things

hhh

Cool -- this is it, what is the scope there? Any special? Tekironix TDS 2002

http://www.youtube.com/watch?v=DEV7m4Y-_kc

vicatcu

2:47 AM

Kortuk i figured you had nothing better to do for the next couple hours

:)

Kortuk

@vicatcu haha

I want to configure the pi.

@hhh Nice!

vicatcu

alternative is install ubuntu

you can dual boot your PC

Kortuk

@hhh that is nothing special, just giving the output on a nice display. you could probably get the same thing many many other ways. I have made a USB scope before, they are not that bad, just a little work.

vicatcu

ubuntu installs along side windows 7 seemlessly

Kortuk

@vicatcu haha. I have a raspberry pi for that!

hhh

2:49 AM

@Kortuk Yes but did you see the breadboard and speed with dry electrode? It must be very very sensitive -- it must handle all kind of things such as leakages or?

What kind of scope is enough for this kind of measurements?

Kortuk

@hhh it is mostly just getting all of the electronics to a high quality.

@hhh the breadboard had the conditioning circuits, the scope was just measuring voltage, that is generally how an EE would use it in that case. The circuit is done and he is demoing final product, now you can just plug in something with ADC and start running it.

hhh

@Kortuk I have a handheld scope at home -- could I do something like this with it?

Or is multimeter enough?

vicatcu

ok i've posted my question to the site: electronics.stackexchange.com/questions/66339/…

Kortuk

@hhh the part that is the work is all the stuff on the electronics, the display is just him graphing Voltage in reference to time. If you have something, like a handheld scope, that gives a decent sampling rate graphical feedback

hhh

@Kortuk you mean I could do this kind of demo with a handheld scope? Yes but then I need to make sure to choose the chips that work in the frequency domain of my scope --.

angelatlarge

3:01 AM

@Kortuk what happened here?

0

Q: What all do i need to build LED bulb

I'm thinking of using few of the CREE LEDs but wondering what all would i need to build a bulb from scratch. Here's what I've got: LEDs (of course) LED high current drivers some sort of rectifier circuit for AC to DC heatsink Any other details or resource you guys can point me to? I'll make...

led current-source

Mr. T?

If someone wants some Mr. Niceguy points, maybe address this in a comment:

-3

Q: Taking baby monitor to Europe

I am taking my baby monitors to Europe. They work with a df 6 volt 110 adapter. Can I switch the adapter to a dc 6 volt 110-240 and add a European plug to use them safely there or do I absolutely need a power converter?

voltage

It's about to get closed, I suspect :)

But I am too lazy

hhh

These guys are big heroes doing this kind of bionic products, extremely fascinating -- making deaf people to hear (a new example about bionic product I found, myo is just another bionic thing)

http://www.youtube.com/watch?v=w_bRzgGusNQ

Kortuk

@hhh Your scope just needs to sample fast enough not to alias.

hhh

"not to alias"?

I have this scope from ebay: ebay.com/itm/…

Do you think it is enough?

angelatlarge

@hhh How is it?

Kortuk

3:17 AM

@hhh sorry, one second. I am sure if it samples at >1Khz it is fine.

hhh

"To give an example of a misleading advert (conveniently using the DSO nano adverts) note on this page it says 1MHz analogue bandwidth, but in this page it says 200kHz (1 Msps). You have to wonder whether that's a genuine mistake :-)"

5

A: Do I need both a multimeter if I buy a digital oscilloscope?

I agree with the others, you will need both. A digital scope is optimal, but depending on funds available bear in mind that you will get a wider bandwidth for the same money with an analogue scope. For example the DSO nano v2 has a 1Msps sample rate which means it will only be able to displ...

This:

**For example the DSO nano v2 has a 1Msps sample rate which means it will only be able to display any signals reasonably up to around 200kHz. It goes up to 80V p-p.**

So it is enough?

When I choose components, what should I pay to attention to -- what kind of things this scope cannot measure -- oscillators with too large frequency? So I cannot use chips with too large working frequency -- this is how I understand it.

Kortuk

@hhh It is both more complex and simpler then that. You can use very high end chips and high working ranges, just at the end you will need a filter to bring it down to what your o-scope can handle, which is roughly 1/2.1 the bandwidth of your scope.

hhh

How can I bring it down?

hhh

3:41 AM

Moved here, became curious why it is "more complex and simpler" :)

Kortuk

@hhh Sorry, I was busy.

@hhh Having a higher working range for your chips can make it easier to have signal integrity issues.

@hhh Ooops! I made an error, I assumed your scope had a lower analog bandwidth then sampling rate.

@hhh So, aliasing. The simplest example I can give.

hhh

Sorry I am a bit lost, perhaps easier to answer main?

I want to make sure the scope is enough to work with something like:

http://www.youtube.com/watch?v=DEV7m4Y-_kc

Kortuk

@hhh Yes, yours is. Sorry, my point was that for a video like that you do not need a high bandwidth scope at all. Think of the frequency involved. you can see it plotting the trace slowly, so it is much below the speed you can see at, which is ~30 Hz.

hhh

3:56 AM

Thank you.

What was the point about measuring things with much higher working frequency than the sampling frequency in the scope? Is it somehow possible to measure higher frequencies or did I misunedrstood?

(to measure higher frequencies by bringing it down, I must say it is an fascinating idea -- would it be possible to bring a high-freuency wave somehow so that it would be observable by the small scope?)

Anindo Ghosh

4:45 AM

Some scopes can display waveforms of frequency faster than their sampling rate, if the signal is perfectly repetitive, by using successive samples from different phases of subsequent cycles of the input signal. There is a term for this technique that I cannot remember now.

Scopes not scores

google.com/patents/US20030107581

W5VO

5:03 AM

@AnindoGhosh Digital Sampling Oscilloscopes

I believe

or aliasing

Anindo Ghosh

@W5VO No, I meant the specific technique. Supersampling? Something sampling.

@W5VO Aliasing, yep.

angelatlarge

I believe @W5VO has an aliasing tongue.

jippie

good morning @all

angelatlarge

@jippie Hallo

jippie

5:18 AM

@AnindoGhosh Aren't those the digital scopes made in the mid-80's?

W5VO

@jippie nonono.... they are very expensive scopes that can sample in the GHz

jippie

@W5VO they did GHz in the 80s;

W5VO

@jippie I mean the technology is not really new, but there's a difference between a digital storage oscilloscope and a digital sampling oscilloscope

jippie

I believe it was the first type of digitalisation in scopes.

Anyway I don't remember the exact name/manufacturer/type/...

angelatlarge

I am sorely tempted to deface @AnindoGhosh's nice answer with references to tin foil hats.

0

A: Howto use/shield NFC/RFID Sticker on back of iPhone 5?

There could be at least a couple of reasons the MiFare card is not being read: The reader is receiving too much random electromagnetic signal from the phone itself, drowning out the RFID sticker's response The RFID sticker is not receiving a suitable RF ID request signal from the reader due to ...

Anindo Ghosh

5:29 AM

@angelatlarge Not a defacement, it's a "scientific footnote" if you do. ;-)

@jippie My point isn't about whether they were made in year xxyy, it's that there are two ways of sampling: Either grab every sample and show it, or grab a sequence of samples from successive cycles of the signal, and show those as one synthesized signal. The specific frequency is irrelevant.

jippie

not sure if the copper tape will work, it reminds me of how a yagi antenna works. Basically I think you may be sticking the NFC exactly at the place where the wave is 0.

what are the english terms again for the knopen en buiken of a sine wave?

The Photon

@AnindoGhosh repetitive sampling

Anindo Ghosh

@jippie minima and maxima

jippie

and in between? where the sine is 0?

The Photon

@jippie zero-crossings

jippie

5:35 AM

there are proper words for those, guys

Anindo Ghosh

@jippie nodes and antinodes

jippie

even in Dutch we have words for it

Anindo Ghosh

@jippie But minima and maxima are also technical terms and are relevant to the context.

@jippie Nodes and Antinodes. Standard pre-1960 terminology, old man!

jippie

@AnindoGhosh I am post-1960

Anindo Ghosh

@jippie Then you call them Minima and Maxima.

jippie

5:38 AM

node, antinode and minima, maxima are not the words I am looking for. They basically all indicate the 'belly' of the sine wave.

Anindo Ghosh

@jippie The way I see it, the wave incident on the RFID tag from the side away from the copper-tape, i.e. from the back of the phone, isn't much affected by the copper tape. Yes, there will be a reflection, but if the reflecting distance is not somewhat similar to the vavelength, this shouldn't be detrimental (i.e. diffraction / destructive interference effects etc won't kick in)

@jippie The "Node" is the zero-amplitude point, the "Antinodes" are the crests and troughs.

jippie

@AnindoGhosh Only one way to find out :) I didn't leave a comment on your answer, because I'm not sure which effect will win. Also I'm not sure if the copper tape will be grounded to the phone, the NFC or neither

@AnindoGhosh Not in this image:

oh just click on the 'image not found'

The Photon

To me, "node" and "antinode" apply to standing waves, not so much to travelling waves...but I'm jumping in your conversation late, so I don't know for sure which you're talking about.

jippie

With a yagi antenna basically wat is happening is fitting the wanted wave / frequency in between the grounded 'sticks' and the reflector

I'm still confused by wikipedia "The effect is a series of nodes (zero displacement) and anti-nodes (maximum displacement) at fixed points along the transmission line."

maybe @AnindoGhosh is right

'nodes' is apparently the word I was looking for :o)

I'm also wondering: If you have a Faraday cage, and you put a radio receiver on the outside of it, but very close to the cage itself. Will it receive much or anything at all?

angelatlarge

@jippie: Free beer on SO:

0

Q: Serial message to integer on arduino

i want my arduino to receive an integer through the serial communication. Can you help me with this? It should be in a form like: int value = strtoint(Serial.read()); Thank you

integer arduino serial

jippie

5:54 AM

you answer it

the question is not clear to me.

he asks something, then gives the solution.

I have no clue what the problem is.

angelatlarge

There is no strtoint in Arduino, right?

jippie

@angelatlarge don't know. I bet there is a library you can load.

angelatlarge

@jippie There is.

jippie

which library should it be in?

angelatlarge

@jippie Well, in C it would be in <stdlib> or <string>, and the function would be atoi.

@jippie I'd have to look in Arduino, I bet String has conversion methods to int

jippie

6:00 AM

Arduino can load the standard libraries I guess

angelatlarge

@jippie Yes, but it not the handholding type of code, you know...

jippie

"handholding"?

angelatlarge

@jippie This is what he/she is looking for:

arduino.cc/en/Reference/StringToInt

jippie

o.

angelatlarge

OK, now that you've made me do the research, I'll go get the cheap points.

jippie

6:02 AM

@angelatlarge arduino.cc/en/Tutorial/StringToIntExample

angelatlarge

@jippie Yeah, except Serial.read() already returns an int. Whatever, that question is a quagmire. Not touching it after all.

@jippie Good luck.

Maybe @AnindoGhosh wants some SO points. He is good with beginners.

angelatlarge

6:53 AM

BTW, did y'all see my clever trick for "shrinking" the circuitlab diagrams?

Maybe I need to post it on meta, but it is so stoopid that it hardly seems worth the bits

user61389

@jippie 23:30 was finishing my job, sleeping was 3:15, if you must know ;)

jippie

@CamilStaps you said you were going to bed, you made me worry.

@angelatlarge what smart trick? (enlarging the circuit with dummy components?)

user61389

@jippie ha :)

angelatlarge

@jippie Yes. Put a piece of junk in there off to the side. Makes the circuit diagram seem wider.

user61389

@angelatlarge this?

angelatlarge

7:07 AM

@jippie I treat it as a "signature" field. :)

user61389

1

A: I'm trying to use 3v LEDs in a 12V circuit, in my car

The issue is that 3.6V is (very likely) not the maximum voltage for each LED, and therefore you don't need a voltage divider. The 3.6V max you are mentioning is most likely the voltage drop across the LEDs when the LED is conducting. It is not the maximum voltage, LEDs, don't really care about v...

jippie

@angelatlarge I refuse to do that, because it is going to be fixed and I don't want my diagrams to look untidy.

angelatlarge

@jippie Out of respect for your future king?

@jippie The diagrams that are up, are never getting fixed.

They are on imgur already.

user61389

@angelatlarge Does it work with whitespace characters as well? I can't test, the plugin is broken in FF

angelatlarge

@CamilStaps Oooh, good idea.

@CamilStaps Probably!

user61389

7:09 AM

I know, I'm brilliant.

2

angelatlarge

Yes, we all know

jippie

@angelatlarge the layout engine will be fixed! (please let me believe that).

angelatlarge

@jippie It's about how the image gets scaled before imgur handoff, and how stackexchange handles imgur images. It will be fixed, maybe, but I doubt very much that the old diagrams will ever change without editing

user61389

@angelatlarge the images are linked to the schematics (otherwise the edit/simulate links couldn't work), so in theory, they could reprocess all images

user61389

By the way, what browser are you using? That editor doesn't work for me in FF, Chrome, Safari, IE...

angelatlarge

7:12 AM

@CamilStaps They could. But they will not, I think

@CamilStaps I am on FF 20.0 on Ubuntu on this machine

And FF 18 I think on Windoze

Haven't tried Chromium

PeterJ

I noticed that post in Meta, it works fine for me in FF 20.0.1 under Win7 x64

user61389

Hmm, this makes me think it could be an XP issue, since I'm experiencing it on all browsers.. but it doesn't seem very likely to me. I'll just wait for the meta post to get solved

angelatlarge

@CamilStaps I use XP on Windows

@CamilStaps No problems with FF

@CamilStaps But I haven't installed 20.0

user61389

@angelatlarge oh :( weird.. 20.0 could be the problem, it worked for me before - let's see if I can downgrade

angelatlarge

@CamilStaps If you have extra time, you could probably look at what everyone is using for browsers. Via the API

user61389

7:15 AM

@angelatlarge heh, asking is easier :)

angelatlarge

@CamilStaps +1

Kortuk

@hhh Aliasing is the term for what happens there. Sorry, I had to step away

@hhh What happens, is that as a frequency becomes higher then your sampling frequency it actually looks like a lower frequency.

jippie

I am running FF 20.0.1 on Win7/64 and the circuitlab thingy seem to work. – jippie 3 mins ago edit

Kortuk

A real example: if I change the state of a light ever second, I turn it on, then off...

1,0,1,0,1,0,1,0...

But you look at me every 2 seconds, you sample at half the frequency of the signal

then you will either see the light always being on, or you will see it always off.

angelatlarge

@Kortuk (removed)?

@Kortuk Is that Niquist theorem?

Kortuk

7:19 AM

Sorry, that was not an accurate statement, you have to sample at a non harmonic, then you start getting very odd things you think I am doing

@angelatlarge Yes, that is what I am explaining.

In digital.

angelatlarge

@Kortuk To whom?

Kortuk

Digital is a little extra complex.

To @hhh, If he is listening and finding it useful at all.

angelatlarge

@Kortuk Ah. Ostensibly he's still here.

Kortuk

The real issue here is, @hhh, if your higher frequencies alias down as lower frequencies you have no way to tell what is being caused by an actual low frequency and what is caused by a high frequency.

So you corrupt your data, this is why people speak so negatively of aliasing.

Does that make sense @hhh?

I can use another example to be more clear.

Stacey Anne

hello, peoples

user61389

7:25 AM

@StaceyAnne hi!

hi @CamilStaps

@StaceyAnne Hallo

morning @StaceyAnne

hi @angelatlarge, @jippie

I'm doing this MIT EE course

and I'm stuck on this: imgur.com/H9D2KMh,b6dysYP

angelatlarge

@StaceyAnne Is this EdX or IRL course?

Stacey Anne

7:29 AM

I think I understand what to do, but the numbers just dont come out right

EDX

Basically, my premise is that Vs*2 = VRs + Vout

for the third question

Anindo Ghosh

@jippie The copper tape will not be grounded on either phone or rfid card.

Stacey Anne

but when I plug the numbers in and solve for Vin, it's not correct

Anindo Ghosh

@angelatlarge No, I stopped dabbling in SO after I realized that there is a lot of Java in there. Java gives me acidity.

angelatlarge

@AnindoGhosh You don't have to eat it, you know.

jippie

@StaceyAnne Ah there are actually two images. Didn;'t see the second image

not that I know the answer to the question ;o)

angelatlarge

7:42 AM

@jippie The links are above the image

Anindo Ghosh

@angelatlarge The meaning applies both ways. I come from a background where "Java will take care of it" is strange as an attitude. I've actually seen someone write Java code that does a bubble-sort of an entire database, by instantiating each record as an object... When the program chokes on a live database, something must be wrong with the database, because "Java takes care of the memory so it is not the programmer's problem"

angelatlarge

@StaceyAnne This is out of my knowledge area

Stacey Anne

wolfram alpha is amazing

angelatlarge

@AnindoGhosh Sounds like some Arduino users we know

Stacey Anne

I just plug in all my horrible nasty equations and it solves for x

Anindo Ghosh

7:44 AM

@angelatlarge No, this was a hardcore Java programmer working on (that itself was amusing) a Mac as a server.

angelatlarge

@AnindoGhosh I actually spent the entire day programming in Java (outside of the parts of the day is wast^H^H^H^Hspent on stack exchange)

Anindo Ghosh

@angelatlarge Well, that makes you a better person than I.

angelatlarge

@AnindoGhosh It makes me looking for a job, trying to learn Android.

Anindo Ghosh

@angelatlarge Did my share of Android development. Gave up when I saw the revenue models were problematic for a small business.

angelatlarge

@AnindoGhosh Oh. So you are the person to ask questions about that. Excellent (remember that circuit diagram? he-he-he-he-he)

jippie

7:47 AM

@AnindoGhosh if your business model doesn't include selling personal information retrieved from the android device, then you're probably facing problems ;o)

angelatlarge

@jippie +1

I think EE.SE is out of free beer for tonight...

PeterJ

@angelatlarge, you can post your Java question on-site, just say you're using this harbaum.org/till/nanovm/index.shtml

angelatlarge

And the free beer on SO is Miller Light

jippie

@angelatlarge yeah, and voting is poor for last 24hrs.

angelatlarge

@PeterJ Grrrrr

@jippie How can you tell? Is that because your rep hasn't doubled?

Anindo Ghosh

7:50 AM

@Angela You can always ask me.

angelatlarge

@AnindoGhosh Oh, @jippie is saying because you haven't been hanging out on the side enough, you haven't voted much?

Anindo Ghosh

@jippie I agree. Personal data peddling is the way of the future unfortunately

Not voted much? Just got my gold badge for voting too much.

user61389

@AnindoGhosh is there a badge for that? You should've told me before!

angelatlarge

@AnindoGhosh I know that you usually spend your daily allotment, but I haven't seen you much in the last few days.

@CamilStaps There is a badge for everything, including taking a dump twice daily for two weeks.

Sorry everyone, it's very late, and I've had 1.5 beers.

@jippie Did you do something on this:

2

Q: Switching Between Two Voltage Supplies

I have been trying to work out a circuit something like the following: simulate this circuit – Schematic created using CircuitLab I want VOUT to be 3V when the switch is open and 5V when the switch is closed. The simulation seems to give me what I want when the switch is open, but not whe...

power transistors diodes protection fet

It has your name on in on the front page, but I can't tell what you did there...

jippie

@angelatlarge yes, and removed it.

PeterJ

7:56 AM

@angelatlarge, only 1.5? We have a term in Australia for that... en.wiktionary.org/wiki/two_pot_screamer

angelatlarge

Ah. I am tempted to edit it to rotate the FETs 90 degrees, but I can't tell if that's good or bad...

@PeterJ We just call it "lightweight" in the US. Two pot screamer.. That's nice.

Anindo Ghosh

8:16 AM

@angelatlarge I've been around - just busy.

Much good karma for anyone who can help me with some basic Proteus PCB layout queries please.

1. How do I create an irregular board edge, i.e. routed slots on the side of an otherwise rectangular board. 2. How do I create an irregular shaped SMT pad? Specifically this concept:

22 hours ago, by Connor Wolf

jippie

@AnindoGhosh In Dutch we have a saying that goes a bit like "from shore into the ditch". Always happy to help you :)

Anindo Ghosh

@jippie Well, overall I'm much more productive with Proteus in a couple of days, than I ever was with KiCAD after months.

@jippie So it's not "Out of the frying pan into the fire", to provide an alternate idiom.

angelatlarge

@AnindoGhosh Really? Is Proteus free?

Anindo Ghosh

@angelatlarge Nope, there's a demo thingie.

jippie

@angelatlarge Why do you immediately assume @AnindoGhosh is a scrooge like I am?

Anindo Ghosh

8:23 AM

@angelatlarge But also there's a Proteus license that's lying unused by client, so free for me when I finally decide to switch.

angelatlarge

@jippie Because he buys cheap-o components at flea markets and talks about the cost of thigs.

Anindo Ghosh

@jippie Oh, I am definitely a scrooge, often not by choice. :-D

angelatlarge

Apr 10 at 20:44, by Anindo Ghosh

@Kortuk My moral code and my dollar code are fighting it out, and my ulcers are in the audience applauding.

Anindo Ghosh

@angelatlarge Well, that's just geography on the first part, and market reality on the second: The only EEs who can afford to design stuff regardless of cost are those on a salary where someone else worries about per-unit device cost.

angelatlarge

@AnindoGhosh Oh, so I should assume that you are more well off than the rest of us hoi-polloi?

Anindo Ghosh

8:26 AM

@angelatlarge I've recently sat through a client discussion where I saw how shaving off 0.5 mm from a board saves them a few hundred thousand dollars.

@angelatlarge There's a flaw in that logic: I'm a scrooge, I'm in probably greater component budget constraint than anyone else here, but the causal relationship isn't because of personal financial constraints, which may or may not be there.

@angelatlarge So, I might well be far worse off than the "hoi polloi" as you prefer to put it, but that isn't why I'm required to shave 2 cents off a design at any opportunity.

angelatlarge

too tired.

Goodnight all hoi-pollloi

Anindo Ghosh

@Angela about your rant in your answer on MOSFET / audio...

angelatlarge

@AnindoGhosh Did I rant?

@AnindoGhosh My answer?

Anindo Ghosh

Just looking at the list of parts the OP said he could work with, I can guess at his geography and possibly the shop he frequents :-)

angelatlarge

@AnindoGhosh Oh, that. I have been getting pretty promiscuous in commenting, have I not?

Anindo Ghosh

8:34 AM

There's at least one shop in the Mumbai component market that keeps those specific FETs, and sells them at insanely low prices.

angelatlarge

@AnindoGhosh Ha! You should add that.

Anindo Ghosh

@angelatlarge So basically for someone on a student budget, those are the components they'll use.

angelatlarge

@AnindoGhosh Neat.

Anindo Ghosh

@angelatlarge Nahh, I don't care to fight the battle where people fail to realize that some economic and geographic realities are different from their own.

angelatlarge

OK, goodnight for realz now.

@AnindoGhosh I think my RadioShack answer was basically your "Mumbai Market" answer

Anindo Ghosh

8:36 AM

@angelatlarge Agreed.

angelatlarge

sleeeeee

p

jippie

night @angelatlarge

user61389

11:26 AM

0

Q: How to setup a development network for the ENC28J60 on XP?

I'm working on an ethernet connection with the ENC28J60. During development, I'd like to connect the chip to my computer directly (i.e. not via a gateway). This computer is running XP, has a primary network interface over WLAN and I do not use the ethernet for other connections. How should I se...

ethernet network-interface windows enc28j60

user61389

Should this be on Super User or Server Fault instead?

PeterJ

11:47 AM

@CamilStaps, it probably would be better for Super User but I just gave it a shot with something that should get it working initially.

user61389

@PeterJ thanks for that, I'm now trying

user61389

I can't figure out what I should set as default gateway on my PC though

hhh

Sorry my time-zone is UTC +2. I gathered some points to the thread below.

http://electronics.stackexchange.com/questions/66342/low-sampling-rate-scope-with-high-frequency-chips-how-to-bring-the-frequency-do

PeterJ

@CamilStaps It should only really matter for external addresses, Internet etc where you need the router. So for an address on local network under the same subnet it shouldn't matter much, but unless you add a new address it'll probably 'break' your Internet connection.

user61389

@PeterJ okay, I'll leave it just blank then. Do I need to fill in DNS / WINS addresses?

PeterJ

11:52 AM

@CamilStaps, no they should be OK to leave empty

user61389

Okay, so I only set the IP of the PC to 192.168.0.1 and of the PIC to 192.168.0.60. Over the serial port, I get debug data, the PIC can read the PC's MAC (verified) and it gets ARP replies. However, I don't see the address in route print - any ideas?

PeterJ

From memory it would be the device not supporting the ARP protocol, although with using static addresses that shouldn't really matter, but I might update my answer to include that point.

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