Electrical Engineering

12:16 AM

Hi everybody. i have a simple question but cannot found the answer : wiki say that a 555 IC take approx 3 to 6 mA. if I plug this to 4 x 1.5 AA batteries (thus 6V). how much time will it last ?

angelatlarge

@tigrou You need to figure out your battery capacity (in mA hours) and use that to figure out how long they will last

tigrou

12:38 AM

@angelatlarge : thanks. around 1200 mA for what i have here. so around 200 hours ? (probably less) i'm right ?

angelatlarge

Actually, I am wrong on that. From wikipedia: "An ampere-hour is not a unit of energy. In a battery system, for example, accurate calculation of the energy delivered requires integration of the power delivered (product of instantaneous voltage and instantaneous current) over the discharge interval. Generally, the battery voltage varies during discharge; an average value or nominal value may be used to approximate the integration of power"

tigrou

in monostable mode , does the 555 consume power when trigger is not activated ?

angelatlarge

@tigrou Yes. Plus don't forget the passive components.

tigrou

i setup a led circuit that illuminate automatically for a small period of time when a aluminium plate is touched with one finger (using a 555 powered by AA batteries) i wanted to know if circuit could stay like this very long (i mean inactivated ) or if batteries will die in a few hours / days

PeterJ

1:14 AM

@tigrou, your 200 hours would be a good ballpark figure assuming 6mA. Although you could measure the current with a multimeter to get a better idea. At that low current and with a bit of headroom in the voltage you should get around the mA hour rating of the battery.

W5VO

1:38 AM

@tigrou You shouldn't be using wikipedia as a substitute for a datasheet :)

angelatlarge

@tigrou Yes, the best way to figure out how much power is stored in some power source is to taste it: use your tongue, not the wikipedia. Just as @W5VO.

W5VO

@angelatlarge After years of training, I can sense the voltages and currents in a circuit with my tongue

4

PeterJ

10

A: Ways to determine polarity (dc) without a meter

WARNING! THE FOLLOWING IS POTENTIALLY DANGEROUS! DO NOT DO THIS IF YOU DON'T KNOW WHAT THE EFFECTS OF THIS ARE! This: Reverse the battery or the diode. [edit] @perilbrain: You're right, I was only considering the low voltage such a charger might have and the suggestive "BIG_R" and "small_r...

angelatlarge

1:59 AM

@PeterJ Nice. I don't know whether to upvote that or not...

angelatlarge

2:46 AM

I think someone is determined to get me the Bouncer badge today.

PeterJ

Shhhh, don't tell @W5VO he'll come along and spoil the fun

angelatlarge

Zap!

W5VO

@angelatlarge Sigh...

angelatlarge

@W5VO True. But I am at -8 for a shiny new badge :)

icarus74

good evening and good morning, based on where you are.

angelatlarge

2:56 AM

@icarus74 Hallo. I am in the center of the continental united states for the last 24 hours. :)

icarus74

:-) good to know... ah, and I see that the mayhem in Boston has come to an end, with the 2nd suspect caught.

angelatlarge

@icarus74 Yeah. Now I can stop watching the damn news and get back to my regularly scheduled drinking.

icarus74

ha ha, sure.

I see lot of these micro servo motors on ebay advertised for application in RC helicopters. Since I'm an absolute noob when it comes to motors, I was a bit stumped because I thought servos are positional with rotation possible in an angular range of +/- 200 deg... so, are these servo motors only for the yaw, tilt, bank control ? I'm assuming that the main rotors are just a geared DC motors, right ?

angelatlarge

3:21 AM

@icarus74 What you say sounds reasonable, but I've never done anything with helicopters or servos for that matter.

PeterJ

3:36 AM

@icarus74, never really done much with them either, but your understanding sounds correct to me, apart from I think the DC motor for the main rotor is normally direct drive instead of geared (could be wrong on that though).

angelatlarge

@PeterJ Elvis has left the building

Anindo Ghosh

@icarus74 Please give me a link, I think you're referring to continuous rotation servos.

angelatlarge

@AnindoGhosh Elvis has left the building

Hi @AnindoGhosh

Anindo Ghosh

@angelatlarge That was a post for him to respond to whenever he's back. It's morning for him now, so he'll be back sometime soon, I guess :-)

@angelatlarge ... and hello there :-)

How's everyone doing on their search for terrestrial intelligence?

angelatlarge

3:52 AM

@AnindoGhosh Well, "we" here just got done with another search

Anindo Ghosh

@angelatlarge Do tell

angelatlarge

@AnindoGhosh It is all over the national news. I live in Boston.

@AnindoGhosh And somehow national news in the US become world news

Anindo Ghosh

@angelatlarge Ahh that. Yes, I've been following it on reddit

angelatlarge

@AnindoGhosh Yeah, that one

Anindo Ghosh

@angelatlarge It's just so sad that people waste their lives destroying other people's lives.

angelatlarge

3:55 AM

@AnindoGhosh It's all sad, and most people here have some sort of (if tenuous) connection to the places/people involved.

@AnindoGhosh I've been glued to the news like a cat to a window today. I am glad it's over, if temporarily. It's just all crazy and stoopid, and ... I am really sad about the young MIT cop in particular for some reason. It's just so sad.

Anindo Ghosh

@angelatlarge I'm thinking there's going to be another round of extra-judicial rights that will be given to Homeland Security, and domestic air travel will become even more invasive in the security area.

angelatlarge

@AnindoGhosh I agree (and am saddened) by point a), but since this didn't involve airlines I don't think b) is likely

Making a junk food run now that it is safe to leave my house.

icarus74

good morning folks

@AnindoGhosh There you go: ebay.com/itm/…

Anindo Ghosh

@angelatlarge Hmm. From my reading though, logic is rarely followed when it comes to funding of security agencies. As well, pre-flight security is the most visible thing any security regime can make changes in to clearly show they're using your tax dollars well. Plus, the masses (the vote bank) don't use airlines so much as the corporate, the professional and the upper middle class. So there's the whole petty envy thing which causes the voters to see increased preflight security as the finger.

(in more ways than one)

icarus74

While the name ("Continuous rotation servo") gives a good deal of hint, but I'm wondering (like a noob), it's the difference from stepper motors is the ability to rotate the other way ??

Anindo Ghosh

4:06 AM

@icarus74 Yes, that would be for the rotor shaft, with a simple modification to the servo. The potentiometer inside is disconnected from the circuit, so the device becomes a continuous rotation servo, with speed control by servo PDM.

icarus74

PDM ?

Anindo Ghosh

@icarus74 Steppers also rotate both ways (bidirectional steppers). The stepper needs multiple control lines, a servo needs 1. Easier for a small MCU to handle.

angelatlarge

@AnindoGhosh But don't you need a driver for both? Meaning that both need some supporting circuitry, and then, do the lines really matter?

icarus74

ah ha...

Rick_2047

hello all

Anindo Ghosh

4:09 AM

@icarus74 Pulse Duration Modulation. It isn't pulse width modulation really. It's a pulse of 1.5 mSec +/- 500 mSec, repeated every 3 to 20 mSec.

icarus74

Okay, found this... nice (and cheap) hack. Perhaps, just what I need.

►

Anindo Ghosh

@angelatlarge A servo already has both logic circuitry and an H-Bridge integrated - that's how they manage to respond to a servo signal with direction and angle actuation. There are also pure analog servos which dispense with the logic part, and according to some, those are actually smoother to operate.

@Rick_2047 Hiya

icarus74

I was actually looking at a geared motor that can go down to 0.1rpm. Found that the only way to do it is set up the right gear-combination on your own. Now that's hard for me. Hard to source the parts and may be, not so easy to rig the gears up right. Stepper motor seemed like a good and easy alternative, although the jerky-ness would be quite telling.

Anindo Ghosh

@angelatlarge The best thing about converting a servo for continuous rotation is that the "+/- angle" servo pulses now act as "+/- rotation speed" instructions. So it becomes trivial to implement speed-controlled, direction-controlled motor movement with just a single control line.

icarus74

@AnindoGhosh Ok, thanks

Anindo Ghosh

4:15 AM

@icarus74 Look at internal planetary gearing, or cycloidal gearing. Both can be achieved with a laser cutter and acrylic or other easy materials, depending on the load and sliding friction envisaged.

@icarus74 Yep, that's the continuous rotation hack I've been talking of.

icarus74

@AnindoGhosh well, given that this is for an educational project, I'll try to stick to whatever is available off-the-shelf. Seeking the services of a rare laser cutter here, is going to be an overkill... though it could be fun thing to do.

Anyway, this project is still a good few weeks away... right now my range sensor is getting all the love.

Anindo Ghosh

@icarus74 Fair. Some good gear sets on ebay too, I recall.

icarus74

BRB

Rick_2047

4:54 AM

is anyone here familiar with how to simulate the dsPIC devices?

in the examples that come with xc16 there is are folders for PC simulation, what software is used to make those?

angelatlarge

@AnindoGhosh It has begun:

politico.com/story/2013/04/…

jippie

6:04 AM

good morning @all

Rick_2047

@jippie hi

jippie

hey rick

Anindo Ghosh

6:32 AM

How does one do strikeout text in an answer, anyone? And hiya @jippie!

@angelatlarge Not surprised.

jippie

<s>strike</s>

angelatlarge

Hi @jippie

jippie

:)

@AnindoGhosh you're welcome ;o)

PeterJ

Didn't realise you could just use s, will save some typing over the full strikeout tag I've always used.

angelatlarge

@AnindoGhosh Like this^H^H^H^H

Anindo Ghosh

6:42 AM

Thanks. And thanks. :-D

Anyone here familiar with Proteus?

Anindo Ghosh

6:56 AM

@Kortuk What's the "Ref: TMBJ" that Russel used on some of his answers?

jippie

7:12 AM

@AnindoGhosh nope, curiuous though what it is as I apparaently have answered some questions corretly on it

Anindo Ghosh

7:29 AM

@jippie Proteus is a pretty powerful schematic capture / simulation / PCB layout product. It is popular in India (though the low-volume fab houses use Orcad instead).

jippie

is it free (as in free beer)? (probably not)

PeterJ

I had a look at it a while back, there are somewhat cheaper versions but from memory what I would have found useful (ARM support etc) was about $1500.

jippie

m.

@PeterJ I'll stick with paper and pencil for now

PeterJ

7:46 AM

@jippie, other advantage to going that way is once the design is done you can cut up the pencil to make resistors and roll your own paper insulated caps.

jippie

@PeterJ I can make literally any value!

Kortuk

9:09 AM

I am probably going to be late getting on in the morning, work just let me get home to sleep, and unlike anindo, I need lots o sleep

jippie

9:21 AM

?

it is almost noon

forgot to have breakfast

Stacey Anne

9:39 AM

it's 4pm here :)

I mean almost 5pm

PeterJ

Getting towards 8pm here, just had some lamb cutlets, tzatziki and a Greek salad that went down rather well, a few beers to wash it down and I'm done :-)

Stacey Anne

you must be in australia

+10

I'm about to make burgers for dinner

:D

PeterJ

Yep, was it the time or mention of beer that gave it away lol?

jippie

always time for beer

I'm puzzled with this remark @PeterJ and @StaceyAnne and @others

The 1.76dB come from the relation between the amplitude of a sinusoidal signal and its power. \$1.76 = 10\log(3/2)\$. — Matt 44 mins ago

Stacey Anne

@PeterJ, the time - there aren't too many places in the world that are ahead of me -

jippie

9:48 AM

I just don't get it where the 3/2 comes from.

I think I can explain the 1/2 from Vpp being double amplitude, but then I still have the factor 3

Anindo Ghosh

Would any of you have any best practices for a footprint for a solder jumper? One that starts life connected, but with a trace that can be cut, and reinstated using solder later.

I've just been using a 0805 footprint, but someone told me the square pads weren't the best way to cut and later rejoin.

jippie

@AnindoGhosh Many Arduino boards have one of those for disabling the auto reset.

and it looks to me like any other footprint for a resistor or capacitor. I guess they use 'your' 0805 footprint.

so I made a useless comment again.

sorry for thaty ;o)

PeterJ

I've never used one in a design but most things I've seen use square pads, probably with pads about the size of 0805 but a lot closer together so it's easy to short without needing any wire.

Now you're forcing me to search through my stuff to find an example, I can't remember what I've seen it on.

jippie

I saw it on an Arduino Mega, lying in front of my :o)

PeterJ

10:04 AM

@AnindoGhosh AT91SAM7S-EK was what I was thinking - they were really easy to use and upon a further look they aren't square, they are rounded at the outer edges. You can download Gerber files / PDFs here to take a look: atmel.com/tools/SAM7S-EK.aspx?tab=documents

Actually just looking and the PDF doesn't show it (only the silkscreen) but the Gerbers should have it.

@jippie, just took a look at what they look like on an Arduino Mega. They're pretty similar too, the Atmel ones probably look a fraction more professional because the solder forms into a nice shape with the rounded edges not that it'd make much difference in practice I guess.

Connor Wolf

10:20 AM

@AnindoGhosh - I've seen a clever idea for an easy-to-solder solder jumper once

hang on, let me draw something.

If you don't mind the crappy webcam image

Basically, the idea is to exploit the surface tension of solder

the solder's surface tension pulls the solder-ball on the concave V-shaped section out into the gap the V forms

Anindo Ghosh

@ConnorWolf Now that is neat!

Connor Wolf

this makes it much easier to bridge to the other side

Anindo Ghosh

@ConnorWolf But jumper removal would be that much tougher?

Connor Wolf

Probably need some solderwick

Anindo Ghosh

@ConnorWolf Hmm... My target audience for this particular board is non-tech people. They'd be able to borrow a soldering iron, but naught else.

Connor Wolf

10:28 AM

Of course, for a production application a simple 0R resistor is by far the best option

PeterJ

I thought it was an intergalactic Pacman about to eat a lunar landing module.

Connor Wolf

that too

You could always have a little trace on the side

and have that be the thing cut

Anindo Ghosh

@ConnorWolf We tried one usability session with the 0 ohm resistors. The audience didn't know which resistor to knock off. Boards dead. :-)

Connor Wolf

hahaha, ok. I can see how that would be an issue

really, for dead-simple highly-idiot-resistant design, I would just use a pin-header, and a jumper block

no soldering needed

Anindo Ghosh

@ConnorWolf One of the reasons I get to see a lot of the "other side" is my typical product audience are people like that.

Connor Wolf

10:31 AM

ahhhh customer service

Anindo Ghosh

@ConnorWolf Yes, that's an option. We're hesitating on that because the entire board costs under half a dollar, while the jumper will add another 10 cents. We're talking Indian economy, a half dollar is a street-side restaurant lunch for many.

Connor Wolf

is there any reason you can't use a plain jumper?

ok, that's a good reason

hmm

I wonder if different manufacturers use different ceramic composition colors for their smt resistors

Anindo Ghosh

@ConnorWolf Heh! Very different problems compared to what western eyes see.

Connor Wolf

Oh, that's an idea

I've seem SMT resistors that have blue resistive composition, rather then black

Anindo Ghosh

@ConnorWolf "Desolder the RED little thingie, leave the others alone!"

Connor Wolf

10:33 AM

is it possible you could get a 0R resistor with a different composition color?

Anindo Ghosh

"Use a blade, cut where the silkscreened scissors and dotted line are printed." is out current thinking.

Connor Wolf

I like "remove the blue resistor"

you could always add some silkscreen annotations to draw attention to the resistor you need to remove

Anindo Ghosh

@ConnorWolf Yes, the reason I mentioned red is, I have a bunch of red 0R 0805 here.

Connor Wolf

oh, cool

is there any reason you couldn't just use those?

Anindo Ghosh

@ConnorWolf Now that the idea has been put in front of me, of course not :-) The real reason was I hadn't thought of color-coding.

Connor Wolf

10:35 AM

hah, glad to help

maybe put a big arrow on the silkscreen too

Anindo Ghosh

I'll run off a batch in each type, red resistor and arrow-shaped traces with a 8 mil shunt trace. Let's see...

Connor Wolf

I'm not sure what your production situation looks like

if you have access to a pick-and-place, the resistor option is much better

if the assembly is by hand, they're pretty equal

Anindo Ghosh

@ConnorWolf Protos are hand-soldered by people who can easily handle 0402 without even a magnifier. Runs of over 50 units go to a pick and place, essentially doubling the cost, if the timeline demands it. Over 500 units, it starts making economic sense to go pick-and-place.

Connor Wolf

ah

well, what volumes are you targetting?

Anindo Ghosh

@ConnorWolf My work ends at prototype approval, so max of 100 units. Then the client does their thing so they decide based on demand and inventory cost.

Connor Wolf

10:43 AM

well, if there is a possibility of 500+ runs, I'd use the SMT resistor option, because it scales far better.
On the other hand, I don't know what the hand-labor option would look like in india. In the US (where I am), doing anything manual is basically not an option unless you want to spend a LOT of money.

Anindo Ghosh

@ConnorWolf Hand labor is amazingly cheap. For instance, a tiny LED board with some 28 parts, all in about 1.5 square centimeter, the hand soldering cost is around 4 to 8 cents (50 unit MoQ).

Connor Wolf

jeez

then do whatever is easiest

Anindo Ghosh

@ConnorWolf P&P matches this price on a much much larger MoQ.

Connor Wolf

yeah, it's just about scaling

Anindo Ghosh

@ConnorWolf It's also about the cost of a P&P = The price in foreign exchange, add the customs duty and bribes for moving paperwork, add in a support contract, and you've more than tripled the US pricetag.

Connor Wolf

10:48 AM

no one makes them locally?

can you buy from china cheaply?

Anindo Ghosh

@ConnorWolf Yes, some few people do buy P&Ps from China, but the support is non-existent so I'm not sure what longevity they get. This is not a comment about the Chinese goods quality, mind you, but the simple matter of service and support.

Connor Wolf

I would assume anything in a price-range that is approachable is basically unsupported anyways. Buy something you can fix, not something you expect to work forever.

Anindo Ghosh

@ConnorWolf There's something from China called SMT DIY PnP which seems to be gaining ground around here. It's essentially an OSH / OSS P&P. Not seen one yet.

Connor Wolf

I've been keeping an eye on the open-PNP project for a fair bit now

I really want to get a hold of a PNP at some point

Anindo Ghosh

@ConnorWolf You begin to see why hand soldering starts becoming attractive? :-)

@ConnorWolf Which one, the China one I mentioned?

Connor Wolf

10:52 AM

screw that, I'd rather build a PNP then hand-assemble a lot of boards

openpnp.github.io/openpnp

Anindo Ghosh

@ConnorWolf No, that Chinese thing is a make-your-own kinda thing with reference designs, I was told.

Connor Wolf

dunno

I guess there are multiple projects

user61389

1:40 PM

Hi all!

ManishEarth

1:51 PM

hi

Dean

2:18 PM

@CamilStaps hi

Kortuk

3:07 PM

@jippie yes, yes it was.

@AnindoGhosh He never once responded to a comment answering, did you find out what it means?

Kortuk

3:20 PM

@CamilStaps allo

@ManishEarth allo

@Dean allo

Dean

@Kortuk Yo

@Kortuk How are things?

jippie

3:39 PM

and back online

I set up my new desk :o)

@jippie pic

Hey all...

@Dean hectic, you?

4:07 PM

@MLM there you go

rawbrawb

@jippie I expected more empty beer bottles and cats ....

jippie

@rawbrawb its new, there can't be a lot of mess on it already

@rawbrawb haven't had time to drink my first beer yet

MLM

@jippie Looks very spacious but the monitors are so far away

rawbrawb

@jippie you were already drinking a beer when you setup the first part!

jippie

i can pull them toward me, they are on a support arm mounted to the desk that can go anywhere within say 50cm or so

MLM

4:09 PM

My workspace is a bar counter which is super high up

jippie

I change the height of the desk with a lever :-p

rawbrawb

and @MLM drinks his beer from a lever!

he IS at a bar after all

MLM

@rawbrawb no levers, just a fish tank

rawbrawb

@MLM then you should have said "bar-like" counter ...

MLM

@rawbrawb it is a bar but now used for something else

I am trying to find a pic

jippie

4:13 PM

I can adjust it from 64 to 90 cm :-)

angelatlarge

Hallo all

rawbrawb

@angelatlarge allo

angelatlarge

4:34 PM

@jippie Do you know that you haven't accepted an answer on your stackoverflow gcc question? Is that intentional or did you forget?

jippie

5:54 PM

@angelatlarge neither

i waited intentionally

and I was starting to forget

angelatlarge

@jippie Yeah, that's what I was wondering.

0

Q: Understanding a circuit label in ICSP programmer for atmega

I am completely new in electronics. I wanted to make a programmer (or burner) to burn my program in my Atmel16a microcontroller. I found a circuit on the internet: (source) Everything is clear, except what is the +5V in the ICSP? Is it same as VCC? Do we have to externally supply 5V to this ...

jippie

@angelatlarge done

user61389

@angelatlarge terrible question, and he accepted an/your answer too quickly.

angelatlarge

@CamilStaps Agreed on the speed., What do you think is wrong with the question (excep the presumption that circuits can be "simplified")?

I actually don't understand what the diode on the base of the BJT is there for.... is it just so that pin 3 isn't lowered by the pull-down resistor?

user61389

@angelatlarge especially that, but also the use of "on the internet" as source, using backticks when it doesn't add anything

user61389

6:00 PM

(+ me having a bad day)

angelatlarge

@CamilStaps Bad day, bad day, bad day

Hi @cipher

cipher

hello

user61389

@angelatlarge yeah, hehe, fortunately I could withhold myself from commenting :)

user61389

Hi @cipher!

angelatlarge

@CamilStaps I don't see the backticks. Am I missing something?

user61389

6:01 PM

@angelatlarge I edited them out ;) electronics.stackexchange.com/posts/66303/revisions

angelatlarge

@CamilStaps Yeah, just saw that

cipher

It seems to me that i should remove my please post a sinpler... thing now

simpler*

user61389

@cipher good idea, thanks

angelatlarge

@cipher To be honest, I am not exactly sure what that diode is doing there exactly. So I was asking @jippie and @CamilStaps on their thoughts.

@CamilStaps Yeah, but then I'll have to edit out my moralistic rants in the answer.

Damn you @CamilStaps!

jippie

?

did I miss anything?

angelatlarge

6:03 PM

@jippie you did

jippie

low hanging rep?

user61389

4 mins ago, by angelatlarge

I actually don't understand what the diode on the base of the BJT is there for.... is it just so that pin 3 isn't lowered by the pull-down resistor?

angelatlarge

@jippie yes

jippie

what diode?

which question?

user61389

0

Q: Understanding a circuit label in ICSP programmer for atmega

I am completely new in electronics. I wanted to make a programmer (or burner) to burn my program in my Atmel16a microcontroller. I found a circuit on the internet: (source) Everything is clear, except what is the +5V in the ICSP? Is it same as VCC? Do we have to externally supply 5V to this ...

microcontroller avr programmer icsp

angelatlarge

6:04 PM

The non-zener.

(Damn you, diagram without component labels!)

The one between pin 3 of the DB-9 and the base of the BJT

user61389

@angelatlarge hint: "The 1N4148"

angelatlarge

@CamilStaps That ain't a label :)

user61389

@angelatlarge okay, okay :)

cipher

@jippie can we replace 1N4148 with 1N4007 ?

jippie

1. find the pinout of RS232
2. remember that RS232 can have logic voltages much higher than 5V. Your average reverse biased BE-diode can only handle 5V, maybe 6

angelatlarge

6:06 PM

@jippie 3 is TX

user61389

@cipher probably, yes. That circuitry is just to pull RESET low for resetting, no need for speed or such, so any normal diode would probably work

jippie

@angelatlarge That can go as low as -15V, from the top of my mind. The transistor will fail

angelatlarge

@jippie Correct

user61389

@angelatlarge wait, do they connect TX to RESET?

jippie

@cipher Probably 1N4007 will work if timing isn't too critical. It is only to reset the controller, not too exciting.

angelatlarge

6:08 PM

@CamilStaps The reset line is lowered by transmitting 11111111...

user61389

@angelatlarge ahh ugly :(

angelatlarge

@jippie Is there a timing difference between those two? I didn't see that in the datasheet.

jippie

@angelatlarge probably by 0000000 because RS232 uses negative logic.

@angelatlarge capacity

angelatlarge

@jippie I didn't know that.

cipher

Now the next question? What if i replaced the transistor with any one NPN ?

jippie

6:09 PM

1N4007 is nice for 50/60Hz, bit above that too

probably rated for a lot more

cipher

@angelatlarge I think yes. That was on wikipedia

jippie

but

for higher frequencies and low currents, a 1N4148 is better.

user61389

@cipher the BC549 is pretty standard, BC547 or so would work too, but you'll have a hard time finding something more used than those two. Any normal NPN would work, probably

cipher

Ok. Thanks @CamilStaps

jippie

@CamilStaps depends on geo location, outside europe, 2N types are more common

cipher

6:11 PM

@jippie and i am in asia!

angelatlarge

@jippie Then to be sure, we'd have to be sure about how PongProg actually programs this. The 000000 idea was just a supposition... But it doesn't seem like timing should be critical

user61389

@jippie ah, didn't know that

user61389

@angelatlarge I don't think it's like the RESET can be used timing critical

jippie

most shops will help give you a useful transistor if you ask for 'low power generic purpose transistor', as long as you don't go to RadioShack, they will probably sell you a car radio.

2

@CamilStaps yes I've seen it for high voltage programming.

angelatlarge

@CamilStaps Right, it needs to stay low during ISP programming

user61389

6:13 PM

@jippie what do you mean?

jippie

but at these currents, ... if you have them lying around,just try the 1N4007. Otherwise, ... you buy 500pcs 1N4148 for €1,- or so

@angelatlarge timing critical reset

angelatlarge

@jippie What do you mean?

You know what worries me: that reset line connected to the collector w/o any resistors in between.

cipher

@jippie I'll certainly go for 1N4148 if i find it :)

jippie

@angelatlarge why so?

cipher

But i have some 1N4007s lying around here, so, wanted to test with 'em

user61389

6:16 PM

@cipher just test then, it won't BOOM, I promise

jippie

@cipher well if it works ...

angelatlarge

@jippie First of all, if RESET is tied to Vcc for some reason bad things will happen, but maybe that's just a DFU error, and we can ignore that. But also, I don't know the characteristics of the RESET line. Hi output impedance, yes?

jippie

it's just that if you have to order from a shop and have to pay postage, ... you're probably making a better deal with ordering couple 4148's

@angelatlarge depends on the controller

angelatlarge

@jippie You mean the MCU?

jippie

is it AVR? => that can be configured with RESET as output

angelatlarge

6:18 PM

@jippie It can, but then you are sure as hell not programming it via ISP.

jippie

I usually try to include a 220E series resistor

@angelatlarge nope, that disables ISP

but it can be that one extra pin you needed.

user61389

If you'd just use a PIC you'd have pins enough

angelatlarge

@jippie If you have a high-V programmer, or write bug-free code :)

cipher

I think this MCU cannot be configured with RESET as output. Here's what my datasheet says: 2.2.7 RESET
Reset Input. A low level on this pin for longer than the minimum pulse length will generate a reset, even if the clock is not running. Shorter pulses are not guaranteed to generate a reset.

jippie

@angelatlarge HV => Arduino, BC547, couple resistors and a few lines of code.

angelatlarge

6:21 PM

@jippie Yeah, I need to build that. Minus the Arduino. Plus bare chip

jippie

I don't know where Arduino ends and non-Arduino starts

angelatlarge

@cipher Yes, you are right. That's good.

user61389

UPVOTE ME!!!!! I AM LONELY. — Kortuk Mar 22 at 21:44

user61389

Seriously? :)

angelatlarge

I'll edit this conclusions of this chat into my answer.

@CamilStaps Maybe that's a sci-fi reference we don't get?

user61389

6:25 PM

@angelatlarge I hope so

user61389

Or he was drunk

user61389

Ah, this explains. Math is dangerous:

user61389

@AlfredCentauri back to my text books I go. I will be doing maths. — Kortuk Mar 22 at 21:12

angelatlarge

@CamilStaps Actually, I like using back ticks for line identification like RESET.

Makes it look less all-caps-ey

user61389

@angelatlarge yeah, that's true. But not for things like '+5V', 'Atmel16a' or so.

angelatlarge

6:34 PM

@CamilStaps Less so. I am not sure that bothers me as much as "Can <_insert component name here_> to this?" titles.

user61389

I find the grey background a little annoying though, especially when there are a lot short words with it.

angelatlarge

@CamilStaps Are you using a laptop?

user61389

@angelatlarge ha, yeah. No, why?

user61389

(I'll just add a UserScript to remove the grey background, and then don't bother anymore ;))

angelatlarge

@CamilStaps You could just tilt the screen back a bit :)

user61389

6:36 PM

@angelatlarge hehe :p I'm out for a while

jippie

\$\oversline{RESET}\$

angelatlarge

@jippie Yes, but that only works for active low lines.

jippie

?

angelatlarge

@jippie Doesn't overline mean "active low"?

@jippie It would be wrong then to use it for active high pins/lines/inputs/outputs.

jippie

@angelatlarge actually I have no clue what the discussion was about.

angelatlarge

6:41 PM

@jippie Ok then. Thanks for your contribution.

:)

@jippie That's too awesome.

@jippie I'd star that, but it isn't funny out of context.

jippie

did I miss today's hangout?

angelatlarge

@jippie We both did

@jippie But I am not sure there was one.

jippie

I had a good reason, had to switch off my PC's because I was setting up my new desk

user61389

@jippie unfortunately, \oversline isn't supported by MathJax.. neither is \textsc.

angelatlarge

@CamilStaps \textsc would be nice.

jippie

6:48 PM

@angelatlarge yes it is

10

A: Test the new \$LaTeX\$ markdown in this Sandbox question!

Yes, I've been shopping around in various (upvoted) answers, but how about a ... CHEAT SHEET To use a formula like \$\frac{Math}{Jax}\$ inline with the text of an answer, surround it with \$, like this: \$\frac{Math}{Jax}\$ To create a formula centered $$\frac{Math}{Jax}$$ within the article...

angelatlarge

Is this on-topic?

0

Q: Why cost of integrated circuits (IC) are higher when purchase online than to local market

Why cost of integrated circuits are higher when purchase online than to local market. For example SN7404N on Digi-Key costs around $2 but same i got from local market in $0.2

integrated-circuit

user61389

@jippie ah, but that's \overline, not \oversline :)

jippie

slip of the tongue

cipher

@angelatlarge I think not

user61389

@jippie I didn't know the function, so just tried.. sorry ;)

user61389

6:51 PM

@angelatlarge no.. I think..? It has to do merely with economical stuff, nothing with manufacturing or so

angelatlarge

I can't quite tell... not exactly shopping... but not exactly EE either...

@CamilStaps Should be flagged for migration to economics.SE?

user61389

Economics – economics.stackexchange.com

Q&A site for economists and graduate-level economics students.

Closed after 206 days in beta.

angelatlarge

I didn't realize one existed. Too bad it got closed.

user61389

@angelatlarge There's a new one: area51.stackexchange.com/proposals/42351/… ;)

angelatlarge

@CamilStaps Though that description... is off-putting: better not ask anything if you are not a grad student at least!

user61389

6:55 PM

@angelatlarge "and those otherwise passionate about the subject" - it's better than the old one, "Q&A site for economists and graduate-level economics students."

jippie

@angelatlarge yeah we should have that on EE ;o)

angelatlarge

@jippie Some people would appreciate that, I am sure.

user61389

@angelatlarge not me :(

angelatlarge

@CamilStaps I know. Your name isn't ____.

jippie

@CamilStaps We'll get you up the rails.

angelatlarge

6:56 PM