Electrical Engineering

user61389

2:02 PM

@jippie ah, I see. For what it's worth, I used two zeners in parallel in this circuit and they're still working...

@jippie two zeners of the SAME voltage in a shunt regulator configuration will actually not blow up. That's because the one which is marginally higher voltage will draw current till the voltage drops, then the second one starts conducting, first one continues conducting. So it'll reach equilibrium. The resistor preceding the zeners to make the shunt regulator acts as a current limiting resistor in this case.

jippie

So tell me @CamilStaps , what does a smart young man like yourself create from all the electronics knowledge you gain?

Anindo Ghosh

Also, if you need a not-very-well-regulated 3.3 Volts from a 5 Volt source, just use 3 silicon fast diodes in series, that'll drop approximately 1.8 to 2 Volts.

user61389

@jippie haha :) I'm currently reinventing the wheel a lot. At the moment working on a standalone text editor with three PICs. Not very useful, but fun :)

jippie

@AnindoGhosh I actually have to parallel resistors too to get enough power dissipation. I think I'm ordering a fist full of these: taiwansemi.com/DSfile/TS2950-51_A07.pdf at € 0.30

@CamilStaps yeah saw that. why three pics?

are you offloading workload or so?

@AnindoGhosh need it for a hungry bluetooth master, which is rated 50mA @3V3

user61389

2:12 PM

@jippie partially task management, and for future compatibility. I divided it into a stdin, processing unit and stdout. That makes it easier to implement PS/2 or VGA support in the future, I hope

jippie

@AnindoGhosh And the voltage on my USB connected to the Arduino can drop to 4V5 and maybe even lower.

Anindo Ghosh

Regarding LDOs, I use L4955V3.3 and 1117-3.3, the latter are amazingly cheap and very robust.

jippie

these are in stock at a shop where I like to go.

Anindo Ghosh

@jippie For use with USB, just go with the 1117-3.3, that's rock solid.

jippie

@AnindoGhosh Sorry, er zijn geen producten die overeenkomen met de zoekterm '1117-33'. Mischien waren uw trefwoorden te algemeen.

Anindo Ghosh

2:14 PM

@jippie Yes. Absolutely. What?

user61389

@AnindoGhosh Tss. Dutch should be a standard.

Anindo Ghosh

Only thing is, the quiescent current is a couple of mA, if that is any concern. Should not be for USB power

jippie

@AnindoGhosh found TS1117-3.3 those ae 35ct, so 5ct more expensive :-p

Anindo Ghosh

@jippie My vendors are better than your ones: ebay.com/itm/…

18 cents each with free shipping.

jippie

@CamilStaps sounds like you really want a tablet :-p

but good practise

Anindo Ghosh

2:17 PM

@jippie I got 100 of them for under 10 cents each.

user61389

@jippie hehe, have to do something, not :)

jippie

@AnindoGhosh I want TO92, breadboard friendly ones

and I want them now ;o)

Anindo Ghosh

@jippie OK :-)

jippie

not in two weeks. I probably forgot what I was trying to build by then.

Anindo Ghosh

If you were in Mumbai I would say come pick up a couple of them for free.

jippie

2:19 PM

sounds tempting

So @CamilStaps where do you buy your components usually? Being a student you probably have to be very economic when it comes to buying parts. Or don't you mind waiting a bit?

Anindo Ghosh

Also, I have been using those SMD LDOs on breadboards by simply soldering them to stripboard pieces. Something like this, but less pretty looking:

Ah found it. This was the one I had ordered. just over 8 cents each :-) ebay.com/itm/…

user61389

@jippie Conrad most of the time, comes in a few days. Microcontrollers I have in stock, thanks to samples :)

jippie

@AnindoGhosh 8ct + 2.99 .. vs mu TO92 @30ct

they're expensive @CamilStaps

user61389

@jippie and VOTI is close to me, so that's where I try to get the fun parts (LCD, transceiver modules)

jippie

@CamilStaps and your PIC's will probably require to be programmed in German mnemonics

Anindo Ghosh

2:25 PM

@jippie No, the 2.99 was just some other seller, I don't spend that obviously. I just use generic stripboard cut into tiny pieces. The only cost is the pins, so say another 1 cent for pins + stripboard piece.

user61389

@jippie true. Fortunately I can subtract taxes with my company, but they're expensive indeed... German mnemonics?

jippie

conrad is german

Anindo Ghosh

@CamilStaps That was a joke

jippie

have you ever looked at their manuals?

Anindo Ghosh

@CamilStaps Us old folks make jokes sometimes

jippie

2:27 PM

I've been doing some business with these guys dickbest.nl

user61389

Ah, yeah, I see. Wow, fun, it exists!

jippie

they have some good 100+ pcs offers

user61389

The products on their homepage don't look that expensive - how are they with shipping fees?

user61389

Oh, wait, that's on their homepage too :)

jippie

depens

user61389

2:29 PM

This one is cute... "klein duimpje" is Tom Thumb

jippie

I bought couple shottkey's in eindhoven @0.90 each

Then I found they were selling them at few ct / 100pcs

user61389

Hehe, easy choice then

jippie

I believe the 4ct ones, so 4 euro's for 100 instead of 4,50 for five

user61389

So now you're stuck with 95 schottky's? ;)

jippie

but @AnindoGhosh is probably right that ebay is cheaper.

never stuck

Anindo Ghosh

2:33 PM

@jippie Some things, dx.com is cheaper than the best eBay deal. Plus they are free shipping on EVERYTHING, no surprises.

jippie

Need to build an input protection circuit for my logicMonitor. That takes 17 diodes at once.

Anindo Ghosh

@jippie Why not use a diode array? Just curious.

jippie

@AnindoGhosh They have some fun modules, but poor datasheets ...

Anindo Ghosh

@jippie Datasheets for components? Or for what?

jippie

@AnindoGhosh because I have 100 diodes lying in one of my drawers

Kortuk

2:34 PM

@AnindoGhosh those are awesome.

jippie

@AnindoGhosh eg the datasheet for the 8 digit display!

Anindo Ghosh

@Kortuk Which are?

Kortuk

@AnindoGhosh look at what I targeted with the reply :)

Anindo Ghosh

@jippie Ahh no I have never bought any modules from dx.com, and even on eBay I only buy if I can independently, or via the seller's listing, find a datasheet that makes sense to me (i.e. I don't read Chinese).

jippie

this one is fun too when it comes to prices (many, not all): ledsee.com

Anindo Ghosh

2:36 PM

@Kortuk I see it now. Those are interesting, especially because they put the caps right on the tiny board. Still at that price they fall short of awesome :-)

jippie

@AnindoGhosh oh come one, even I had the display running in couple hours

Anindo Ghosh

@jippie Yeah, something like that huge 7-segment display I showed you on video yesterday. It came with no datasheet (picked it up from the local electronic components street), but I found one online while standing at the shop. After I came home, I realized the datasheet I had found was in Chinese. Fortunately the schematics look the same in either language ;-)

jippie

Yeah I was wondering, what would you do with one of them, apart from using it as a night lamp for the kids bed room

Maybe a bit bright for that though.

Kortuk

@AnindoGhosh Hey, I cant find the comment from olin telling him did he believe in magic.

user61389

Hey guys, what do you use for terminal software? I used RealTerm, but it's broken somehow now...

jippie

2:42 PM

putty

Kortuk

2

Q: Do I really need to solder headers to a shield? Or can I just plug it into my Arduino?

I recently purchased an MP3 Player Shield for my Arduino. I bought a couple of headers to run through the shield's holes down to my arduino. Is this TRULY necessary (for testing purposes)? Or could I just plug it in and down to the Arduino. P.S. Since our dear friend Olin had trouble understand...

jippie

let me find the right URL

@CamilStaps chiark.greenend.org.uk/~sgtatham/putty

Kortuk

@AnindoGhosh you responded, do you know where olin made the comment about magic he refers to?

user61389

@jippie I have putty, but you can't set and clear the RTS line with it, can you?

user1095332

Can I invite you to help here: chat.stackexchange.com/rooms/8230/…

jippie

2:43 PM

why would you want that?

use perl or python ;o)

user1095332

Because that would be very helpful

Anindo Ghosh

@jippie Those were bought to address a specific problem. The stairwell on our apartment building can be very dark when the landing lights are off, even in the daytime... and house numbers are not readable. To avoid random people ringing the bell just to ask what house number this is, I put together a PIR + house number display. It lights up when anyone walks onto the landing, providing light as well as telling them "If you ring my doorbell by mistake you will be beaten with a big stick"

so to speak

user61389

@jippie It's connected to MCLR, like in Microchip's bootloader (AN1310 I believe)

Anindo Ghosh

@Kortuk That comment was deleted. However, I did not react to that comment, but to Olin's other comment saying "Naming it a shield was arrogant".

jippie

@CamilStaps make a feature request :o)

Kortuk

2:45 PM

@AnindoGhosh I can see deleted comments, no such comment exists on the question or on his post.

user61389

@jippie ah, but there should be some software.. :(

jippie

@AnindoGhosh ah you have an angry wife, don't you? I noticed that during the hangout as well I believe.

Anindo Ghosh

@Kortuk I saw a "will it connect by magic" comment on the question before Olin's answer appeared. No idea where it went, and frankly I didn't think about responding to it, since the "arrogant" comment really triggered me off.

jippie

@CamilStaps I used perl for that exact problem, but I can't remember which library.

Kortuk

@AnindoGhosh ahh, I see he had another comment that he edited a few times before the timer ran out, so my must have thought better of it before 5 minutes was up.

user61389

2:47 PM

@jippie And I don't know perl.. yet :o thanks anyway!

Anindo Ghosh

@jippie No, the wife never faces the random bell-ringers, since I work from home and she goes to work.

jippie

@CamilStaps python is a more modern bet

but perl is fine too

Anindo Ghosh

@Kortuk The comment was inflammatory in the version I saw, maybe he figured his wrist would get slapped.

user61389

@jippie neither do I have experience with python.. can't java use the serial port?

jippie

I think we should get a list of forbidden words in chat @Kortuk

Kortuk

2:49 PM

@AnindoGhosh or he realized how much of a dick it made him sound, but he seems to have done so quickly. I can't believe he honestly thinks he is going to teach arduino users to not say "shield"

@jippie ????

jippie

let's start with putting java as #1

Kortuk

ha.

@CamilStaps you can use java with serial ports.

arduino's environment is in java

jippie

still think python is the better bet.

Anindo Ghosh

@Kortuk That was one question where I wanted to stand up and applaud the newbie for standing up to the beard, and also standing up to you for not noticing how "douchey" we were being to him. :-)

jippie

especially since it is free as in free beer and free thought.

user61389

2:50 PM

@jippie You're probably right, but I need something quick and dirty

jippie

and java is run by Oracle who are making a mess of it.

user61389

@Kortuk cool, thanks. Going to look into that!

Kortuk

@CamilStaps it may not be as easy as you think, the last time i used it it was really really poorly documented.

Anindo Ghosh

@Kortuk I think he genuinely might need medical help. And I say this with absolutely no disrespect intended. At my age (and greater), we tend to sometimes get socially inept and intolerant. Some course correction can help.

user61389

@Kortuk were you working with a command line application or GUI?

jippie

2:51 PM

2

Kortuk

@AnindoGhosh yeah, in the US they just label you as an engineer when you have no social skills and teach to to say, "i am good at math"

@CamilStaps writing code.

Anindo Ghosh

@user1095332 Hi... What's that about, then? What help is needed?

Kortuk

@CamilStaps arduino's environment has a serial port monitor that works pretty well, I cant remember if I could toggle RTS and such.

Anindo Ghosh

@Kortuk In Gurgaon, they slip a knife between your ribs in the parking lot some dark evening.

Kortuk

that is from java.

@AnindoGhosh ouch, so dark.

user61389

2:53 PM

@Kortuk okay, is it free?

Kortuk

@CamilStaps the arduino environment, yes!

Anindo Ghosh

@Kortuk Gurgaon is not my idea of a model place to show off as "This is India", but for some situations, like that one, it has its good points.

Kortuk

@CamilStaps arduino.cc/en/Main/Software

jippie

@Kortuk DTR

user1095332

@AnindoGhosh About this question: math.stackexchange.com/questions/353712/… How to represent the image kernel for image processing as a discrete convolution formula.

Kortuk

2:54 PM

@jippie nope, he is going to toggle RTS, your mind will explode.

user61389

@Kortuk even open source, nice. Perhaps I should reconsider my prejudgements on Arduino...

Kortuk

@CamilStaps lol

user61389

@Kortuk I mentioned RTS here, but DTR too in the end, probably.

Kortuk

@CamilStaps pretty sure RTS is the device side and DTR is computer side.

Anindo Ghosh

@user1095332 Ahh I see. Hmm, there are a couple of people around EE who might be ideal to jump in. Also the people in signal processing SE might be even more apt.

jippie

2:56 PM

@Kortuk I toggle DTR @pc side

in perl

user61389

Talking about Arduino, it's coming to beta soon. I made a community ad for it, but not sure if it's okay to come up with one so late? The last one from me was pretty late already...

user61389

@jippie RealTerm allows you to toggle DTR too.

Kortuk

@jippie I enjoyed that.

jippie

@CamilStaps does it end in .exe?

user61389

@jippie uh, I guess

jippie

2:57 PM

then I refuse to download it.

oh wait putty ends in .exe too

hmmm

user61389

@jippie you're on linux?

jippie

@CamilStaps yes

Anindo Ghosh

Hmm, RTS is not asserted by device. It is asserted by computer.

Why did I remember it the other way around?

jippie

wrong hemisphere?

user61389

@Kortuk For reference, the Arduino environment doesn't allow you to toggle RTS and so.

Kortuk

3:01 PM

@CamilStaps sorry buddy

Anindo Ghosh

@jippie That was brilliant. Two thumbs up!

user61389

Back to the original prejudgements :)

Kortuk

I was hoping it would when @AnindoGhosh did not correct me :)

jippie

@CamilStaps it is still open source

Anindo Ghosh

@Kortuk Since I don't know what I was to correct you about, I need to read back in the transcript.

user61389

3:02 PM

@jippie yeah, well, okay. +0.5 for Arduino then, if you must ;)

Kortuk

@AnindoGhosh arduino software terminal having access to RTS and DTR.

Anindo Ghosh

Ahhh I see. @CamilStaps You're looking for terminal software that toggles serial status lines, on which platform?

jippie

@AnindoGhosh just slap @Kortuk for making you forget ;o)

Kortuk

@AnindoGhosh thank you!

crap, late for brunch!!!!

will finish dealing with olin when I get back.

See you guys in a bit.

jippie

enjoy @Kortuk

user61389

3:03 PM

@AnindoGhosh I'm on windows XP, but if really necessary I have Ubuntu 10.04 somewhere down there

Anindo Ghosh

@Kortuk Hmm, I've never used Arduino's terminal software, but why did you recommend that? I missed the thread of conversation there.

user61389

@Kortuk bye!

Kortuk

@AnindoGhosh it was written in java, which I know that library can handle it, and it is easy to get free software for @CamilStaps

@AnindoGhosh I was hoping it did have access to that.

Anindo Ghosh

@CamilStaps Oh, OK. Let me check the various terminal software I have, to see which one does RTS toggling.

jippie

10.04? speaking about masochism

Kortuk

3:04 PM

see, once you get @AnindoGhosh on the case :)

user61389

@AnindoGhosh cool, thanks in advance!

Anindo Ghosh

@Kortuk For some reason I've never needed to use the Arduino serial monitor. Mostly because I do all my status indication through fancy combinations of flashing LEDs, old old habit from the late 80s.

jippie

oh just use a push button

user61389

@jippie desktop version, that is. The server is at 12.04. I'm really not into Ubuntu, so I have no idea if that's latest or not

Anindo Ghosh

Something which IBM adapted from, with the original PC, using the beep codes for error conditions at bootup.

jippie

3:05 PM

it is 3 yrs old and almost 6 versions behind

user61389

@jippie XP is better then windows vista, 7, 8, so...

jippie

/me is out for a while

type to you guys later

user61389

@jippie goodbye!

Anindo Ghosh

@CamilStaps I have RealTerm which is open source and allows RTS toggling.

@jippie Bye

user61389

@AnindoGhosh hehe, yeah, I have it too, but it's broken! :o

Anindo Ghosh

3:10 PM

Broken?

:8857108

user61389

Well I'll just try a reinstall.

Anindo Ghosh

Termite is installation-free, and has a status like toggling plugin. Free again.

user61389

It thinks I'm sending 0x00 all the time, while I'm not, I checked that with putty and some Microchip tool

Anindo Ghosh

compuphase.com/software_termite.htm

OK one more, this one came as a recommendation during some workshop I attended, maybe AD or something: sites.google.com/site/terminalbpp

I don't use this last one but it does have neat data visualization capability, something like Processing does, using arbitrary serial data.

user61389

@AnindoGhosh thanks for Termite & that one, I'm now trying!

Anindo Ghosh

3:14 PM

@CamilStaps I have Termite installed though I use RealTerm almost all the time. It's one of my default applications in my startup folder.

So RealTerm is running the moment my PC is booted.

user61389

@AnindoGhosh that's geeky :) Realterm gives me a "UART receiver framing error" now, what would that mean?

Anindo Ghosh

@CamilStaps It's trying to open the wrong hardware port.

@CamilStaps I'm geeky. Most of my PCs have at least one, maybe two serially connected devices under various forms of manipulation; All of my PCs, even my laptop, have the good old serial port - To the extent that I had a serial + parallel port card installed on the newest machine because it didn't come with one.

user61389

@AnindoGhosh that's weird. It says it all the time now, also on another port which is working.

Anindo Ghosh

@CamilStaps restart, something has taken up the serial ports and did not release resources.

user61389

@AnindoGhosh haha, cool (why not use USB to serial converters?)

Anindo Ghosh

3:19 PM

@CamilStaps I do that too, but at least a couple of devices (e.g. my Garmin GPS) don't play nice with USB2Serial

user61389

@AnindoGhosh Hmm, no time. Have to get some French fries.

user61389

@AnindoGhosh I've heard more people about issues with the converter. That's too bad...

Anindo Ghosh

@CamilStaps This is of course a Garmin ruggedized GPS, from before every smartphone had GPS. I still find it useful when I am shooting in adverse conditions. It's survived several dunkings in various kinds of water.

user61389

Anyway, I'm leaving now then.. Thanks for your help, all! :)

Anindo Ghosh

@CamilStaps Always welcome

user61389

3:21 PM

@AnindoGhosh I know the thing! We used one in Scotland last year, since a phone can't handle GPS for two hours while a Garmin module uses 4 AA batteries for 36 hours or so!

user61389

Bye! :)

Anindo Ghosh

@CamilStaps Yup.

@CamilStaps Also when I fall into rivers etc while shooting, my phone doesn't survive.

angelatlarge

@AnindoGhosh @jippie I figured it out

Hi all

Anindo Ghosh

@angelatlarge Hi, and it is 42.

angelatlarge

@AnindoGhosh It not entirely unlike 42

Anindo Ghosh

3:26 PM

@angelatlarge I never claimed it was. :-)

angelatlarge

3:43 PM

Found a tiny typo in ATmega328 datasheet. Do I get a cookie?

@AnindoGhosh How would you recommend responding to this: electronics.stackexchange.com/questions/64737/…

jippie

@CamilStaps bad stop/start bits

or parity / baudrate

@AnindoGhosh probably the difference between usb<=>serial and usb<=>rs232

Anindo Ghosh

@angelatlarge I would recommend making it an answer, fleshing it out with additional info / example disassembled code, and starting the answer with "Writing up my comments as an answer, as suggested".

angelatlarge

@AnindoGhosh But I thought we had a perfectly decent answer in the linked-to post, no?

Anindo Ghosh

@jippie Not just RS232, but the RTS-CTS flow control the device requires.

jippie

@angelatlarge what is the typo?

angelatlarge

3:53 PM

@AnindoGhosh In fact, I flagged the question as a dupe, or am I not seeing something?

jippie

@AnindoGhosh those can be looped back

angelatlarge

@jippie It's insignificant. Page 160, table 18-2, first row should have OC2A not OC0A

jippie

m

what you call insignificant, your timer won't work with it

Anindo Ghosh

@angelatlarge While I felt it was a dupe when I first saw it, here's my personal viewpoint - This question is structured very differently to the original, provides more identifiable visual detail, hence is likely to be found and read by a lot more future researchers... Hence it deserves to stand on its own merit, at worst with a note mentioning that much of this is covered in the earlier question.

jippie

or your comparator

Anindo Ghosh

3:55 PM

@jippie No, the stupid Garmin device then decides not to talk to papa anymore.

jippie

m

serial comms can be a drama

My GPS has bluetooth, that's why I'm trying to set up the bluetooth master.

I realized I also need some level shifters to make it work properly.

Anindo Ghosh

@jippie My GPS predates Bluetooth, which is one of those newfangled fads ;-)

angelatlarge

@jippie Shifters are nice.

Must reboot, brb

jippie

Think I'll make a small module for it, a SIL module

Anindo Ghosh

@angelatlarge Shape shifters are nice.

jippie

3:58 PM

Do you think @AnindoGhosh and @angelatlarge that a 3V3 to 5V level shifter will work with a BS170?

Anindo Ghosh

@jippie Not reliably, no. Tried it.

jippie

:|

what would I need that is in a TO92 package?

what property is making it unreliable?

Anindo Ghosh

@jippie On warm days it doesn't work, with the AC on it works well. Or was it the other way around?

jippie

fairchildsemi.com/ds/BS/BS170.pdf

Anindo Ghosh

@jippie Vgs

jippie

3:59 PM

th

I expected that

V
GS(th)
Gate Threshold Voltage V
DS
= V
GS
, I
D
= 1mA All 0.8 2.1 3 V

Anindo Ghosh

@jippie Not "Vgs.th", that's just marketing crap. The th value is for unrealistically marginal conduction.

jippie

I beg to differ, but you have to understand well what it means

Anindo Ghosh

@jippie I believe in Figure 5 more than in Vgs.th

jippie

hum hum hum

give me an alternative :-p

I have to go out shopping

that 'give me' remark was retoric

Anindo Ghosh

@jippie I understand what it means, I just don't see that value as sufficient for reliable conduction when your 3.3 "high" could conceivably be pretty close to the actual voltage needed for solid conduction. Lower than that, and you're creating a tiny little heater ;-)

@jippie Wait, let me see what I finally used before shifting to a TI level shifter IC...

jippie

4:03 PM

yes I noticed the 3V thing

oh I can check for a proper level shifter too

Anindo Ghosh

irf.com/product-info/datasheets/data/irlml2502.pdf

ebay.com/itm/…

I bought them after the BS170 frustrated me.

jippie

argh I need converter prints for that

Anindo Ghosh

@jippie What is a converter print?

jippie

smd => SIL

I can't breadboard those

I have to find more converter prints anyway I guess

out for shopping, back in a couple minutes.

angelatlarge

@AnindoGhosh What's with the private listing?

Anindo Ghosh

4:07 PM

@jippie I use stripboard, the pins are perfectly spaced for soldering to adjacent tracks (inter-track spacing on my stripboard is 0.5 mm)

@angelatlarge Private listing? Ahhh that listing must be over or something. It was valid when I bought it. Hold on.

abdullah kahraman

Hi guys

Anindo Ghosh

@angelatlarge Does this link work?

ebay.com/itm/…

angelatlarge

@abdullahkahraman Hallo

Anindo Ghosh

@abdullahkahraman Hiya

angelatlarge

@AnindoGhosh The previous one worked too, just says "private listing"

@AnindoGhosh This one is the same. I can see the item, but it says "private"...

Anindo Ghosh

4:09 PM

@angelatlarge Ohhh that simply means the seller wants to know your country before showing shipping cost, usually.

angelatlarge

@AnindoGhosh Oh. Howdya figure that out? I am impressed

Anindo Ghosh

that seller has some of the best prices and fastest delivery for various components, as long as you are buying listings of 10 or more.

@angelatlarge Because I dabbled in eBay selling at one point. Got rid of a lot of old photo gear that way.

user61389

4:23 PM

@AnindoGhosh hmm, a reboot didn't work.

Anindo Ghosh

@CamilStaps Then what about other terminal software?

user61389

@jippie I have no parity, 8 data bits, 1 stop bit, that's default, isn't it?

user61389

Eh, wow. It's alive!

user61389

I think the reboot worked after all. I was suddenly surprised when my computer said 'hi.' to me.

Anindo Ghosh

@jippie I got myself a couple of these, you'll love them given your fascination with LED numeric displays: ebay.com/itm/…

angelatlarge

4:26 PM

@CamilStaps I am always surprised when my computer does that.

user61389

@AnindoGhosh well thanks for the reboot idea :) I'm going to save the other software in my bookmarks for when I need something else!

Anindo Ghosh

@CamilStaps :-)

user61389

@angelatlarge it's like the beginning of the first movie of The Matrix trilogy, if someone has seen that

Kortuk

@AnindoGhosh I have a similar issue.

jippie

@CamilStaps pretty much, yes

@AnindoGhosh it is not so much a facination with led numeric displays, I just need an easy to read display for another little project that outgrew the thought experiment.

@AnindoGhosh how is this as an alternative for the BS170:

pdf1.alldatasheet.com/datasheet-pdf/view/22302/…

This parameter seems a bit high: Propagation Delay Time (data input to output) High to Low Level

H->L 10V => 5V 850ns(typ) 1600ns(max)

hmm intersil datasheet is a lot friendlier with that parameter

angelatlarge

4:54 PM

Does anyone know, while I have SPI turned on on AVRs, I can still manually bit-twiddle the MISO and CLK lines, right? Or no?

jippie

@angelatlarge I believe you can override the output driver

it was in the erreta

angelatlarge

@jippie I mean once SPI master finished sending, you can just PORTB |= (1<<3) or something (PB3 is the MOSI line on ATmega328)

Anindo Ghosh

@jippie That datasheet link is not opening for me. What's the part number?

angelatlarge

@jippie Nothing in ATmega48A/PA/88A/PA/168A/PA/328/P datasheet errata when searching for "SPI"

jippie

40109

Anindo Ghosh

4:59 PM

@jippie huh?

jippie

¿

I just found a SOT-23-6 converter print in my drawer :o)

but it is only a single one

Anindo Ghosh

@jippie Obsolete part, not recommended for new designs?

jippie

it is basically a 6 pin SOT-23 I think

@AnindoGhosh what's wrong if it is in stock?

of 35ct

Anindo Ghosh

@jippie Yes, sot23-6 is 6-pin SOT23.

@jippie Then why not - it sure beats fudging around with multiple FETs

jippie

futurlec.com/Datasheet/CD4000/CD40109.pdf

Anindo Ghosh

5:02 PM

@jippie back to your adapter PCBs - Have you got any standard strip-board PCBs around?

jippie

sure several kinds, but not too different

Anindo Ghosh

@jippie 5V, 10V and 15V Parametric Ratings - Not rated for 3.3?

jippie

Rated > 3V according to the ST datasheet

Anindo Ghosh

@jippie So if you have any SOT23 part, just place it on the stripboard and see, it's very easy to solder it onto the tracks and make a breadboard adapter

@jippie Maybe I missed that, if it says so then you should be OK.

jippie

@AnindoGhosh it was the datasheet you didn't open

@AnindoGhosh disagree, the pin spacing is way too narrow

Anindo Ghosh

5:07 PM

@jippie ok.

jippie

I only have 2.54mm spaced boards

Anindo Ghosh

@jippie Too narrow to reach the holes, not too narrow to just fit the pins onto the edges of the copper tracks.

@jippie what is the space between the copper strips, on a 2.54 spaced board?

jippie

two sot-23-6 pins fit on a single copper trace

I think you have to make a drawing

user61389

Does anyone have a RS232 C18 library for a PIC18F46K22? Or know a place where to look?

jippie

not me

user61389

5:30 PM

Oh, wait, there appears to be something built-in, hmm

angelatlarge

@CamilStaps I am an AVR person, not a PIC person

user61389

Hey, @angelatlarge, I see you removed your answer at electronics.stackexchange.com/q/64764/17592. Why? That was not the intention of my comment.

angelatlarge

@CamilStaps I know. But your comment made me realize that I was answering a different question than the one OP asked. I didn't think you were suggesting that I remove it, but that seemed like the best idea anyway.

user61389

@angelatlarge okay then, your choice

angelatlarge

@CamilStaps Besides, @jippie needs the rep, and I cleaned up on free beer last night :)

Anindo Ghosh

5:39 PM

@CamilStaps You cannot use the 1.1V AREF to measure a 3.7 Volt input.

jippie

Oh I'm about to include a circuit diagram :)

@AnindoGhosh right

user61389

@AnindoGhosh what do you mean? Did I say that?

jippie

nor the 2V56

@AnindoGhosh so let me remove that :)

rawbrawb

hEElo @all

Anindo Ghosh

@CamilStaps Sorry, I meant @jippie - I answered your message because you had referred to it.

angelatlarge

5:41 PM

@rawbrawb hallo

jippie

my answer needs some extra work ..

user61389

@rawbrawb hello

Anindo Ghosh

@rawbrawb Hiya! How are we today? Less overworked, hopefully, this being SUnday and all?

user61389

@jippie nah, it's an arduino question

Anindo Ghosh

@CamilStaps Cheap shot!

rawbrawb

5:43 PM

@AnindoGhosh I wish, I gotta get some stuff going for when ASia wakes up in 6 hours.

@angelatlarge @CamilStaps cheers!

jippie

@CamilStaps indeed. A PIC question would be done now.

Anindo Ghosh

@jippie BTW if he's using a boost reg to power the 'duino, without an LDO hybrid regulation mechanism, his Vcc will be way too unstable to use the device for measuring the Vbatt with any meaningful accuracy. He'll get the precision, but for nonsense values.

user61389

@jippie well, okay, I think it's time for a PIC.SE then! :p

Anindo Ghosh

@CamilStaps PIC is for dweebs ;-)

user61389

@AnindoGhosh realterm on startup is for dweebs ;)

rawbrawb

5:47 PM

@AnindoGhosh so how is your stuff going? you were travelling lots, hopefully getting lots done.

Anindo Ghosh

OK, @jippie or @angelatlarge or whoever, here's a solution that might actually work for that dude's purposes: Use a separate reference voltage, need not be precisely 3.7 volts or whatever (let's say a 3 Volt Zener), fed off the Vcc. Read the ADC values for both, and take a ratio (or use map()).

That way, when Vcc drops even down to 4.5 Volts, the 3.7 V to 3 Volt ratio will remain stable. Better yet, if there is a differential ADC mode (I forget if the Arduino AVRs have one), he can measure the difference between reference and Vbatt, using one of the internal AREF values for greater precision.

@rawbrawb Going good. Watching movie with wife. Nice Sunday.

Later all.

rawbrawb

@AnindoGhosh ciao

user61389

@AnindoGhosh have fun

angelatlarge

@AnindoGhosh bye

@jippie Hmmm... I am not so sure about being able to use SPI pins when not sending SPI while SPI is enabled... My MOSI pin seems to stay high after send is done, even after CBI (clear bit) on it. Of course, I could be forgetting something simple...

rawbrawb

@CamilStaps added to your LCD question. Thanks by the way, a lot better than the usual questions that have been flowing through lately.

user61389

5:56 PM

@rawbrawb thanks, and thank you for the very useful answer! :)

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