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[00:23:25] <doublebeta> Compensate ALL the ppms! (x ALL the things)
[00:24:04] <doublebeta> ppm = parts per million, right? hm, 3 parts per million. Lol damn, that really is like zero swing
[00:41:28] <Valen> yardleydobon: if your making less than 100 of them use the biggest chip you can fit into your device
[00:41:58] <Valen> the extra $ the IC cost will be paid for in your time and your product not sucking ;->
[00:42:13] <Valen> the U4's are nice btw, ADC and all the good stuff
[00:46:31] <yardleydobon> i have a teensy coming. i'm interested to see if i have the same problem when using it's twi module.
[01:16:12] <inflex> lo there vanquish
[01:16:14] <inflex> ooooops
[01:16:18] <inflex> I mean valen... who's not here
[03:20:26] <inflex> wonder where Ziph is
[03:53:34] <ziph> inflex: Bok
[04:16:54] <inflex> heya
[04:20:10] <ziph> heya
[04:20:13] <ziph> wassup?
[04:20:39] <ziph> inflex: GP are too darn fast, I have a 4 layer board arriving before all of the parts for it. :)
[04:34:56] <inflex> ziph: yeah, similar here
[04:35:06] <inflex> ziph: got a batch of boards arriving and I've not even raised the money for the LCDs
[04:35:16] <ziph> inflex: :(
[04:35:35] <ziph> Fortunately I have a $10k project coming up that will fund my more speculative project. ;)
[04:35:46] <inflex> ooof
[04:35:51] <inflex> I could do with something like that in all honesty
[04:36:02] <inflex> anyhow, I've got some new data for you on a new build of the LOM with a new reference resistor
[04:36:13] <inflex> just wondering if you had any interest - no problem if you're busy/bored
[04:37:15] <ziph> It's an interesting one too, it gets to control an object twice the size of a car that is mounted three stories up to some ridiculous precision. :)
[04:37:26] <ziph> Sure, what were the conditions it was taken under, linear ramps?
[04:37:30] <inflex> oooh nice nice
[04:38:04] <inflex> just an overnight~midday run
[04:38:07] <inflex> nothing special
[04:38:15] <ziph> Not in the oven?
[04:38:20] <inflex> http://dxp.me/s.log
[04:38:33] <inflex> nope, no oven this time, is the first "real world" run
[04:38:54] <inflex> but here's something interesting... I can't work out what the damned 3rd column is *laugh*
[04:39:13] <inflex> I actually cannot find the serial call in the firmware yet
[04:39:43] <inflex> but, when I do a 2:3 x-y comparison, there's what looks like a comb-filtering effect on the data in the last ~10,000 entries
[04:39:57] <inflex> (eg, if you're doing long-term sampling of a frequency domain
[04:40:04] <inflex> could just be pure coincidence
[04:44:37] <inflex> ermm... odd, okay, it's the first column of.... oh hell, now I know what it is... in my serial log data program I made it put down the utstamp *facepalm*
[04:45:39] <inflex> ziph:
http://dxp.me/serial.log.gz that's the big one, about 130,000 entries
[04:45:55] <inflex> ...waiting for it to upload
[04:46:06] <inflex> ok, uploaded.
[04:50:34] <inflex> btw, this is measuring a 10R 0.01% 4-wire resistor
[04:54:12] <ziph> The second two columns are the interesting ones?
[04:56:44] <inflex> nah, it was just bogus data that I was looking at in the end
[04:57:00] <inflex> it was simply normal hiccups within the stream over time
[05:11:22] <ziph> I wonder how much of the noise is due to temperature quantization..
[05:17:05] <inflex> tough to say - though the ADC data sheet certainly shows that there's going to be a moderate amount of it down at the levels I'm working
[05:20:08] <ziph> Isn't it a digital thermometer?
[05:24:17] <inflex> O_o
[05:24:54] <inflex> I really need to improve the oven/fridge thing I have, because I need to see what it can do across a broader temperature range, eg, 0->40'C
[05:33:41] <ziph> Sigh, I'm going to end up writing another accounting system.
[05:42:31] <CapnKernel> Like the world needs another one!
[05:45:08] <ziph> There aren't any good ones for electronics inventory.
[05:48:31] <crazy_pete> you know i have heard that honestly ziph
[05:48:45] <crazy_pete> (that there are not any good ones for electronics inventory)
[06:22:56] <crazy_pete> how (or can i) match an avr arch to a particular part? Very specifically i have an atmega32u4 and i wonder what arch it is?
[06:52:44] <karl_> oops, missed crazy_pete
[06:52:49] <karl_> the avr-libc page has a list of them
[06:56:33] <karl_> crazy_pete: avr-libc pages have a list of atmega partnames and avr arch
[06:59:29] <crazy_pete> oh thanks i was looking at the avr-libc pages but didn't find that one
[07:00:00] <crazy_pete> (I admit i sort of got lost on the avr-libc site just now anyway) :)
[07:00:02] <karl_> oh, it's there somewhere, maybe on the interrupts list page
[07:00:03] <karl_> one tick
[07:00:24] <crazy_pete> give me a lame start and i really am looking at avr-libc as i type
[07:01:56] <crazy_pete> http://www.nongnu.org/avr-libc/user-manual/using_tools.html <----- i was looking at that
[07:02:29] <crazy_pete> i guess the thing to do is compile it with -E (? stop at preprocesser) and see what it defines the ARCH macro to :)
[07:03:08] <karl_> hmm, I can't find it myself right now.
[07:03:12] <crazy_pete> bah i am really embarrassed
[07:03:14] <karl_> yeah, that one.
[07:03:19] <crazy_pete> it is on the page i just linked to
[07:03:25] <crazy_pete> i didn't scroll down far enough
[07:03:27] <karl_> hehe,
[07:03:31] <crazy_pete> lol i started reading the page
[07:03:38] <crazy_pete> i just got to the list you mentioned :)
[07:04:23] <crazy_pete> it's an AVR5 like most atmega
[07:04:26] <crazy_pete> (or all?)
[07:06:22] <crazy_pete> naw scrolling down further reveals AVR6 and AVR51 atmegas
[07:09:24] <karl_> any reason you really care about the arch?
[08:14:32] * inflex gets back from watching X-men First Class
[08:17:31] <ziph> inflex: Seen
http://www.heraldsun.com.au/news/more-news/julia-gillards-plan-for-open-trade-with-developing-countries/story-fn7x8me2-1226176691788 ?
[08:17:47] <inflex> mmm... more crap to read
[08:18:12] <inflex> oh lordy *sigh*
[08:18:59] <inflex> I've been pretty happy with Labor for a while, despite a lot of groanings from a lot of the public... but damn, doing moves like that just pushes our own population then into the poverty line harder
[08:19:32] <inflex> I'm already struggling to compete with my stuff, now I'm going to have to compete against 1/100th the labour costs and half the part costs directly *sigh sigh*
[08:19:37] <inflex> nice way to kill innovation
[08:21:42] <ziph> Also, yay for not being able to eat something not poisoned.
[08:22:03] <ziph> Mmm, Indian Arsenic Coke(R).
[08:23:15] <inflex> yum yum ymu
[08:23:34] <ziph> There's bottled drinks from China for kids in most places now.
[08:23:46] <ziph> Here, have some Chinese river water!
[08:23:52] <inflex> heh
[08:24:01] <inflex> I'd say it'd be dangerous of Labor to include China on that list of countries
[08:24:06] <inflex> it's hardly an emerging market
[08:24:18] <ziph> Why? We only just stopped sending them foreign aid a few months ago.
[08:25:46] <inflex> and yet here I struggle, like today, to find enough money to buy food for us.
[08:26:05] <inflex> and tomorrow will be harder
[08:29:52] <Tom_itx> when will US receive foreign aid?
[08:30:10] <ziph> You don't get enough of that from China? :)
[08:30:37] <Tom_itx> all that's doing is taking all our jobs and making unemployment rise
[08:30:58] * CapnKernel lives in China...
[08:31:27] <ziph> Yeah, but once the GOP eliminates social security, unemployment will be a huge boon to productivity figures.
[08:31:31] <CapnKernel> Apparently our balance of payments figures were looking too healthy
[08:32:19] <vanquish> inflex: ahoy!
[08:32:30] <vanquish> oh
[08:32:31] <vanquish> :(
[08:32:40] * vanquish is Forever Alone
[08:33:02] <CapnKernel> I have to tell you guys, China is not a developing country.
[08:33:05] <CapnKernel> Not in my experience.
[08:33:16] <CapnKernel> They have the money, the technology, the leadership to do whatever they damn want.
[08:33:46] <ziph> So are you saying Australia perhaps shouldn't have been paying them foreign aid? :)
[08:33:49] <CapnKernel> This "Oh we're a developing country" is just an excuse they trot out, both nationally and individually, in order to justify acting like selfish animals.
[08:33:59] <CapnKernel> China? Are you fucking kidding me?
[08:34:02] <vanquish> CapnKernel: china is no longer a developing country much the same way as your little sister is no longer developing
[08:34:16] <CapnKernel> After two kids I'd say you're spot on!
[08:34:23] <vanquish> :)
[08:34:26] * karl_ laughs
[08:35:05] <CapnKernel> 500m people in China's rural areas are still pretty bad off. But that's because of policy decisions by their government not to make progress on wealth distribution. They *want* to have a two-tier system of haves and have nots.
[08:35:31] <karlp> works out so well for everyone else right?
[08:35:31] <Tom_itx> sounds like the US
[08:35:41] <CapnKernel> It's ok to call a country "developing" when its economy is below critical mass and there's no money in the government's pockets to do anything about it.
[08:35:47] <Tom_itx> only the haves are at the top and bottom ends of the economy
[08:35:49] <CapnKernel> Neither of these can be said about China.
[08:36:02] <Tom_itx> the bottom end receives hand outs continually
[08:36:35] <Tom_itx> the middle pays for it all
[08:36:37] <CapnKernel> Makes me really angry that when you point out something shitful that China's doing, either in or out of China, to hear Chinese people say "oh, but we're only a developing country".
[08:36:44] <CapnKernel> Really fucking angry y'all hear???
[08:37:12] <mrfrenzy> I must have missed how this discussion relates to microchips
[08:37:13] <CapnKernel> By "when you" I mean "when I", when I'm talking to folks.
[08:37:28] <Tom_itx> mrfrenzy they come from china
[08:37:32] <CapnKernel> ziph started it
[08:46:04] <Tom_itx> so mrfrenzy what are you working on?
[08:46:25] <ziph> Me? I never start off-topic discussions.
[08:46:32] <mrfrenzy> currently on my "day job", writing a test that my python students will take tomorrow
[08:46:54] <ziph> You teach snake charming?
[08:47:17] <Tom_itx> you should post it somewhere so i can learn python
[08:48:22] <mrfrenzy> there are many good online classes
[08:48:24] <mrfrenzy> just pick one
[08:51:59] <Tom_itx> so far my only need for it was to tweak some exhisting code
[09:23:59] <amee2k> what do you guys use to draft board layouts for later copying to copperclad with a sharpie?
[09:24:37] <ziph> amee2k:
http://dorkbotpdx.org/wiki/pcb_order
[09:25:01] <ziph> amee2k: Seems to work well even if you only have dirty copper clad. ;)
[09:25:06] <amee2k> isn't that a boardhouse?
[09:26:17] <amee2k> my coperclad is fine and i don't feel like paying 30EUR for a tiny board
[09:32:45] <Tom_itx> i don't use a sharpie
[09:32:51] <Tom_itx> i use a laserjet
[09:33:11] <Tom_itx> and eagle
[09:33:14] <amee2k> well, mine doesn't transfer so i don't
[09:34:28] <amee2k> i've got some old photocoated stock, but not sure if it is still good. i remember someone mentioning they stop working after a while
[09:34:45] <Tom_itx> try it
[09:35:05] <Tom_itx> it'll either develope or it won't
[09:35:25] <amee2k> i only ever do single boards, and most are small anyway so the sharpie is fine
[09:36:01] <amee2k> this time the layout is a bit more involved because some of the ground connections are moderately critical
[09:36:16] <amee2k> so i'm looking for a way to visualize it and quickly try different things
[09:36:24] <Tom_itx> cut it out with clear tape
[09:36:31] <Tom_itx> and an xacto
[09:37:18] <amee2k> i've used tapes to do ground planes, but i usually use rub-offs for pads and the pen for connections
[09:37:42] <amee2k> you done phototransfer before?
[09:38:18] <Tom_itx> not the photo sensitive type
[09:38:22] <Tom_itx> http://tom-itx.dyndns.org:81/~webpage/etching/etch_index.php
[09:38:31] <amee2k> when i got my hands on that board stock i did some looking on the internet, but noone seems to know how to do that exactly
[09:38:49] <amee2k> all the howtos elaborate to great length how to lay out the board
[09:39:12] <amee2k> then go "now print it, expose and develop. then drop it into the acid and wait until it looks finished"
[09:39:27] <amee2k> thats entirely not useful. >_<
[09:40:10] <amee2k> hmm i see
[09:40:22] <amee2k> nice tank though :)
[09:40:34] <Tom_itx> ask anonimasu he's done the chemical method
[09:41:00] <Tom_itx> guess he's not in this channel now
[09:41:04] <Tom_itx> but in others
[09:41:39] <amee2k> hmm none that i am in :/
[09:42:27] <Tom_itx> try #seattlerobotics
[09:42:46] <amee2k> yep, there he is :)
[09:45:45] <karlp> amee2k: I'm with ziph, I only use copperclad because we have a pcb mill in the office,
[09:46:06] <karlp> otherwise, everything got sent out, mostly to dorkbot these days,
[09:46:29] <karlp> if it was worth making more permanent than a breadboard, it was worth it
[09:47:49] <amee2k> besides the whole turnaround time thing, i don't like the idea of the board costing twice as much as the entire rest of the project
[09:48:29] <amee2k> making boards is pretty much the last thing i have yet to find a quick and affordable solution for
[09:48:33] <karlp> you must have some particularly large boards, with particularly cheap components then.
[09:49:18] <amee2k> no, i have so small boards that the shipping and setup fees typically double or triple the price of a board order
[09:49:37] <amee2k> plus i'm not /that/ good that i get every board right on the first shot
[09:49:38] <karlp> really, have you looked at dorkbot?
[09:49:50] <amee2k> yeah, they want 15$ for shipping alone
[09:50:14] <karlp> ... or $5 for standard first class
[09:50:20] <amee2k> the components on that board i want to do here are like 5
[09:50:32] <amee2k> how long does that take to arrive? two weeks?
[09:50:45] <karlp> in iceland, it arrives in 3-5 days,
[09:50:58] <karlp> then customs sits on it for up to 10 days, but they do that regardless of how it ships
[09:51:22] <amee2k> i've ordered stuff with "standard shipping" from overseas before. fastest i've had was like 10 days counting from the time the email with the shipping notice arrived
[09:51:22] <karlp> sure, you can't beat the convenience of being able to make your own,
[09:51:37] <amee2k> exactly
[09:51:55] <karlp> but if you don't already have a setup for it, these days, given the shrinking size of parts, I can't imagine wanting to get srated with a chemical etch tank
[09:52:28] <karlp> you still have to drill yourself
[09:52:51] <amee2k> i'm fine with etching and drilling
[09:54:01] <karlp> I'm not trying to stop you :) I junk think the running costs of a home drilling/etching/washing setup, plus the space, are a pretty high price to pay for faster turnaround
[09:54:10] <karlp> s/junk/just/
[09:55:05] <karlp> actually, to tell the truth, if I was looking at setting up from scratch at home, I'd probably be looking at the price of a halfdecent cnc machine, and doing isolation routing instead of etching
[09:57:12] <amee2k> well, i got a 1kg bag of etchant and some old board stock for free from a friend a couple years ago
[09:57:56] <amee2k> other than that my "setup" consists of some sheets with rub-off symbols, a pair of paint markers, and two of the cheapest glass trays they had at ikea
[10:00:27] <CapnKernel> amee2k: Asking "what do you guys use to draft board layouts for later copying to copperclad with a sharpie?" is like asking "Mr. Jones, are you still beating your wife". It assumes we're mad enough to dick around with Sharpies.
[10:01:14] * karlp giggles
[10:01:27] <CapnKernel> Me, I do my schematic capture and board layout in KiCad, then I print it to drafting paper and make the board using UV sensitive PCB.
[10:01:45] <CapnKernel> I can go from on-screen to having a board in my hand in an hour, including setup and packing away.
[10:02:17] <amee2k> do you honestly want a reply to that one?
[10:02:31] <CapnKernel> amee2k: If you want to know more, look here:
http://capnstech.blogspot.com/2011/05/playpause-making-pcbs-at-home.html
[10:03:15] <CapnKernel> It is cheap, fast and easy.
[10:03:52] <amee2k> please just do both of us a favour and put me on your ignore list to protect your sanity from my doubtlessly inferior questions
[10:03:57] <CapnKernel> Only thing I can't do at home is multi-layer. And then I get my boards through a service like Seeed.
[10:04:16] <CapnKernel> amee2k: You don't think you're over-reacting?
[10:04:52] <amee2k> yes, i am
[10:04:58] <CapnKernel> You're welcome to come here all you like. It's your channel too. I've learned a lot here, and you may too.
[10:06:42] <CapnKernel> There is an art to asking good questions, and it's not about experience or ignorance.
[10:09:18] <karlp> CapnKernel: it's ok, he wants to use the supplies he got for free. they're important :)
[10:09:28] <CapnKernel> I would too.
[10:10:08] <CapnKernel> amee2k: Use a green scourer such as on my blog post, and then scrub it with paper towels soaked in acetone until the paper towels stop turning black. The boards will work fine.
[10:10:56] <CapnKernel> Do you guys know about the "bashphorisms" bot in #bash? It is a bot which spouts truisms on the questions newbies ask. For example, go into #bash and type "!b0". And if that tickles your fancy, try "!b1" and so on.
[10:15:37] <CapnKernel> Well, that killed the conversation!
[10:21:32] <Ikarus> hrm, anyone have a list and comparison of all soft-USB client stacks for Atmel AVR ?
[10:22:49] <grummund> the #bash people seem to have a fetish about bots
[10:24:35] <karlp> Ikarus: for parts with built in usb or without?
[10:24:53] <Ikarus> karlp: soft, so without
[10:25:34] <CapnKernel> Well there's V-USB
[10:25:43] <CapnKernel> Probably the most popular
[10:25:46] <karlp> CapnKernel: that's a very thorough post about home pcbs
[10:25:49] <Ikarus> yeah, but I'm looking for a comparison
[10:25:59] <CapnKernel> karlp: Thanks!
[10:26:03] <Ikarus> not just the stacks themselves
[10:26:35] <CapnKernel> Next time I'm going to use a sponge with neat FeCl3 and dab it on. Apparently all done in 45 seconds.
[10:26:45] <karlp> v-usb is gpl, not lgpl
[10:27:08] <CapnKernel> v-usb can also be commercially licensed, IIRC
[10:27:11] <karlp> true
[10:27:25] <karlp> are there any other comprehensive software only usb implementations?
[10:27:29] <karlp> there's the usbtiny stuff
[10:33:53] <karlp> heh, love the garden fork trick
[10:35:07] <CapnKernel> Yes it's very useful. Not my idea though.
[10:35:22] <Tom_itx> http://dicks.home.xs4all.nl/avr/usbtiny/
[10:35:28] <Tom_itx> i think that one is the most copied
[10:52:50] <inflex> lo there Tom_itx
[10:55:28] <amee2k> CapnKernel: of course it did. and when you figure out why, you'll realize why i overreacted too
[11:09:29] <karlp> anyone have any success/pain stories attempting to save 4 bytes to eeprom after the power goes out? using the BOD, plus a cap of ?? to keep it up long enough for the write to finishe?
[11:20:24] <Ikarus> karlp: only looked at it theoretically, it seems doable, but the gotcha is the EEPROM write requires relatively stable power
[11:20:53] <grummund> amee2k: there's ##pcb if you're interested
[11:21:39] <karlp> Ikarus: yeah, I've read one success story, and a lot of people saying, "don't even try, it's not going to work when you really need it"
[11:22:25] <Ikarus> karlp: you need a big enough cap so the voltage is nominally stable
[11:27:45] <ziph> inflex: It just occurred to me that this trade liberalisation will be occurring simultaneously with the import-adjustment-free carbon tax. :)
[11:33:52] <grummund> Anyone care to review/sanity-check my circuit for correctness? -
http://i52.tinypic.com/263j677.png
[11:36:01] <grummund> it's for a bicycle tail light... answer in ##electronics if you prefer.
[11:37:09] <vectory> grummund: any reason to use 6 resistors in parallel instead of one for R1?
[11:37:39] <grummund> yeah, the lowest i have is 10 ohm ;)
[11:39:00] <vectory> looks interesting, i suppose its gonna blink, is it?
[11:39:19] <grummund> slow flash (hopefully)
[11:51:12] <theBear> i'm no expert, but the back to back transistors with the flasher looks a little suspect to me, like there should be 1 more resistor
[11:51:33] <theBear> unless the big led doesn't flash
[11:51:42] <grummund> good luck ;)
[11:51:57] <grummund> sorry wrong chan :-/
[11:52:43] <grummund> theBear: where?
[11:53:49] <theBear> the current limit, and the left side of the flasher,i'd have to doublecheck stuff i constantly and will always forget like the way the arrow in a transistor should point, but it just looks like the current limit will make that side of the flasher ineffective
[13:55:39] <RikusW> amee2k: here is everything you want to know about pcb etching ->
http://www.p-m-services.co.uk/index.htm
[14:09:33] <vanquish> hai #avr
[14:09:40] <vanquish> i have a need to record timestamps
[14:09:54] <vanquish> i'm trying to find the most efficient way of doing this
[14:10:08] <vanquish> i need millisecond accuracy
[14:10:36] <vanquish> i'm thinking i'd name the datafile as the current date
[14:10:46] <vanquish> and then count seconds?
[14:10:51] <vanquish> but that needs 9 bits
[14:11:06] <vanquish> i think it needs to be byte aligned
[14:11:16] <vanquish> sorry, 17 bits
[14:11:27] <RikusW> so you want to minimize the data size ?
[14:11:32] <vanquish> yeah, ideally
[14:11:38] <vanquish> or come up with a better scheme
[14:11:59] <RikusW> and over how long will it run ? hours ? weeks ?
[14:12:03] <vanquish> i'm gonna have billions of data points, with a milisecond timestamp
[14:12:08] <vanquish> more space i save the better
[14:12:13] <vanquish> but should be byte aligned i think
[14:12:29] <vanquish> years, fingers crossed, but it would be intermittent
[14:12:34] <RikusW> how often will you take timestamps ?
[14:12:45] <vanquish> data will be on ring bufer
[14:12:54] <vanquish> so it'll only safe the most recent however much
[14:13:44] <vanquish> RikusW: the avr will check inputs as fast as it can, or will be clocked ever 1/10/100 milliseconds (not sure yet
[14:14:10] <RikusW> and store it to eeprom ?
[14:14:15] <RikusW> flash ? ram ?
[14:14:23] <vanquish> you thinking i could use 3 bytes and mask the higher/lower to count seconds/milliseconds?
[14:14:31] <vanquish> storing on sd card
[14:14:43] <vanquish> 1-2gb
[14:15:28] <RikusW> how often will you take timestamps ?
[14:15:33] <RikusW> many per second ?
[14:15:39] <vanquish> yes
[14:15:54] <vanquish> i have an rtc that will interrupt each second
[14:16:00] <vanquish> and i will reset a timer on the avr
[14:16:20] <vanquish> and grab the mS value from it when i measure the data
[14:16:22] <RikusW> you could make a record that stores data per second
[14:16:35] <RikusW> so you only have to store the millisecond part
[14:16:41] <vanquish> hmm, i like
[14:17:03] <RikusW> and then store the seconds part and length in the header of each record
[14:17:13] <vanquish> that would lower disk io overhead too
[14:19:34] * vanquish ponders
[15:21:09] <DarkSector> Can I use the I2C and ADC simultaneously in the Mega* ?
[15:21:20] <DarkSector> I mean the 28 pin versions only
[15:23:31] <RikusW> you just won't be able to use ADC4 and ADC5
[15:24:10] <DarkSector> Okay so to enable the ADC I need to connect AVCC to VCc
[15:24:12] <DarkSector> *VCC
[15:24:22] <DarkSector> but to enable the I2C what do I need to do?
[15:24:41] <RikusW> you always need to connect vcc to avcc
[15:24:49] <RikusW> even when not using adc
[15:25:10] <RikusW> you need to setup some IO registers for I2C
[15:25:34] <DarkSector> okay, that I'll google
[15:25:34] <DarkSector> thanks
[15:25:52] <RikusW> when using adc you might want to put a 10uH coil between vcc and avcc
[15:26:07] <RikusW> and a 100nF cap from avcc to gnd
[15:26:08] <DarkSector> RikusW: oh! why so?
[15:26:13] <DarkSector> yeah I know about the caps
[15:26:17] <RikusW> filter
[15:26:19] <DarkSector> but why the coil?
[15:26:29] <DarkSector> okay is there a tutorial on understanding solenoids?
[15:26:39] <DarkSector> I know about the caps but nothing on the solenoids
[15:26:46] <RikusW> the 10uH coil is tiny
[15:26:54] <RikusW> need only supply a few mA
[15:27:07] <RikusW> it improves filtering
[15:27:07] <DarkSector> yes but I've seen it many datasheets
[15:27:14] <DarkSector> and have never understood it
[15:27:31] <RikusW> a cap resists change in voltage
[15:27:40] <RikusW> a coil resists change in current flow
[15:27:41] <DarkSector> oh and that in current
[15:27:42] <DarkSector> nice
[15:27:49] <DarkSector> okay I'll read up more on that on these terms
[15:27:51] <DarkSector> thanks a lot RikusW
[15:28:03] <RikusW> wikipedia ?
[15:28:12] <RikusW> look for inductor
[15:47:46] <Jan-> Can I drive a piezo sounder directly from an AVR pin?
[15:57:10] <devilsadvocate> Jan-: how much current does it need?
[15:59:19] <Jan-> I uhoh.
[15:59:25] <Jan-> It'll prob'ly be from the its box.
[15:59:28] <Jan-> er, bits box
[16:02:06] <grummund> with a limiting resistor it should be okay. use two pins in flip-flop fashion
[16:18:28] <Jan-> how big of a limiting resistor
[16:18:35] <Jan-> But yeah. AC drive.
[16:18:41] <Jan-> I've heard of people using PWM pins.
[16:25:38] <vectory> thats what i heard
[16:26:14] <vectory> and wondered how the negative side of the amplitude would be generated
[16:26:46] <grummund> start with 1k and see if it's loud enough
[16:27:15] <vectory> as in, it wont be smooth anyhow
[16:29:56] <grummund> pwm might be an option, using complimentary pins.
[16:29:58] <grummund> but piezos don't have a massive bandwidth anyway
[16:32:25] <nintendo> i'd like to amplify the signal of a voltage source. is there a possibility to limit the voltage of a solar cell to a maximum value, let's say 0-5V? i thought a zener diode may be the right part but i'm not sure
[16:33:12] <Casper> zener would eat up all unused power
[16:34:35] <nintendo> well, i guess it would distort my measurement, too
[16:35:32] <nintendo> i'm just afraid it could kill my op amp by setting something like +12V
[16:40:57] <Casper> resistor in series with a zener
[16:41:18] <Casper> so the zener never conduct until the voltage excede the zener
[16:41:28] <Casper> once it happend the resistor limit the current
[16:41:38] <Casper> making it not wastefull, while saving the opamp
[16:42:01] <Casper> another way would be to make a voltage dividor with 2 resistors
[16:42:16] <Casper> so your 12V become 5V or alike
[16:42:22] <nintendo> hmm sounds good
[16:43:12] <devilsadvocate> if it is a solar cell, then how does it matter if its wasteful or not? once the zener is in play, you're going to lose energy anyway
[16:44:51] <nintendo> well, the solar cell acts as a sensor... the usual measurement voltage is approx. <100 mV... as light is turned on/sun shines, the voltage rises up to 12-20V
[16:45:56] <devilsadvocate> are you trying to draw energy from the cell?
[16:46:37] <nintendo> nope, i just need the potential difference (no current flows)
[16:47:07] <devilsadvocate> then a resistive dividor that scales the output from 0-max to 0-5 should do fine
[16:49:46] <nintendo> the (negative) side effect would be a diminishing of my measurement voltage... but that solution sounds fine
[16:49:56] <nintendo> i just tune up the op amp hehe
[16:54:25] <Casper> nintendo: actually, the mesurement voltage might actually be more usefull that way
[16:54:31] <Casper> than to limit it
[16:56:21] <nintendo> the limitation would be only to protect the electronic device (TS912IN op amp)
[16:57:00] <Casper> do you want to mesure or just an on/off? or want to know which panel have more light?
[16:57:14] <nintendo> i haven't tried it out yet, but +20V sounds kinda brutal to me - although, there is no load
[16:58:27] <nintendo> i have three solar cells in series to measure light polution at night (which is indeed measurable)
[16:58:44] <nintendo> why solar cells as sensors... don't ask me ;-)
[16:59:14] <raden> Anyone know of a tutorial somewhere on doing long delays ? 10 - 30 minutes ?
[17:00:36] <specing> raden: decrement an unsigned long until it reaches 0?
[17:00:54] <raden> hmmm
[17:02:43] <nintendo> so i'd like to amplify the input signal, A/D-convert it and send it to a PC for further analysis/graphing... it works fine at night but as soon sun rises, the voltage of the solar cells rises too from ~50mV to max. 20V
[17:03:15] <nintendo> i'm just afraid to kill the op amp
[17:03:40] <raden> nintendo, what u trying to do ?
[17:04:46] <nintendo> raden: limiting the "high voltages"
[17:05:54] <nintendo> but Casper and devilsadvocate already gave me valuable hints, thanks guys :)
[17:07:32] <Casper> nintendo: in general, never excede the supply voltage
[17:07:39] <devilsadvocate> nintendo: you need it to be able to measure the low voltages as well?
[17:07:46] <Casper> if your opamp is 5V powered, then never excede 5V
[17:08:02] <Casper> but really, the dividor seems to be your best bet
[17:08:25] <nintendo> devilsadvocate: only low voltages are measured, yes
[17:08:33] <nintendo> Casper: exactly
[17:09:54] <devilsadvocate> nintendo: then you may be better off with the zener + resistor setup
[17:10:06] <devilsadvocate> nintendo: assuming you dont care of the >5V range
[17:10:20] <nintendo> right
[17:11:31] <nintendo> hmm, any rules of thumb for dimensioning the resistor?
[17:11:42] <nintendo> i'll try both methods :P
[17:18:38] <Casper> nintendo: 1/4 watts shall be fine
[17:19:07] <nintendo> thanks alot Casper :)
[17:19:08] <Casper> the official value is to find the current going throught it and the voltage drop and calculate the wattage dissipated...
[17:19:33] <Casper> but unless you go very low you won't dissipate much
[17:22:34] <nintendo> the solar cell datasheet tells something about 81 mA @ 5V but i've measured like 40 mA @ 7V
[17:23:43] <nintendo> (a single solar cell) since there are 3 of them in series
[17:33:11] <nintendo> time for zZzZ.. thanks alot guys
[17:35:00] <abcminiuser> Well thank christ Microsoft finally fixed this bug:
http://support.microsoft.com/kb/2607576
[17:38:27] * Landon bets his boss could possibly run into that problem
[17:38:59] <Landon> but then all of his applications are probably spread across some pseudo-cluster of windows machines
[18:45:25] <CapnKernel> grummund: Re your bike light flasher
[18:45:56] <CapnKernel> I don't think much of using R1* to limit current
[18:46:08] <CapnKernel> The current through the LED will change with temperature and phase of the moon.
[20:52:42] <inflex> lo folks
[20:52:50] <inflex> hiya CapnKernel - back in AU or still over seas?
[21:00:41] <Valen> anybody have any handy circuits for driving big LED's over a wide current range
[21:00:46] <Valen> want to get a feel for inductor size
[21:01:07] * Valen also plots using 2Mhz synchronous buck converters wewt ;->
[21:07:01] <Casper> you should give number
[21:07:09] <Casper> because big led refer to the size, not current
[21:09:14] <Valen> 8A or so
[21:09:21] <Valen> max
[21:09:31] <Valen> but I'd also like to run it at around .5A
[21:09:49] <Valen> and the inductor gets much larger at lower duty cycles
[21:27:58] <sparrW> I'm using an AVR to drive serial shift registers which then drive a string of LEDs
[21:28:14] <sparrW> I'd like to speed up writing to the shift registers.
[21:28:48] <sparrW> I'm thinking of putting a parallel-in-serial-out shift register in between the uC and the serial-in shift register
[21:29:17] <sparrW> then the AVR can spit out 8 bits in two(ish) cycles, and they will get sent down the line much faster by the higher frequency shift registers
[21:29:25] <sparrW> viable idea?
[21:30:04] <Valen> hmm
[21:30:25] <Casper> what about using the synchronious uart?
[21:30:27] <Valen> I wonder if you could use a clocked serial port to do your xfers
[21:31:00] <Valen> Casper: how fast does that go? SPI can run at something like fosc/2 or so as i vuagley recall?
[21:31:17] <Casper> F_CPU/16 or /8 for x2 mode
[21:31:40] <Valen> parallel > serial would probably be faster its true
[21:31:50] <Valen> but your serial line would be fairly humming
[21:33:01] <sparrW> Casper: I'm using hardware SPI for F_CPU/2 (I think)
[21:34:04] <sparrW> I'd like to improve on that significantly. If I bang 8 bits out the data port in two cycles then that will be an 8x speed increase (assuming the clock on the shift registers runs at least 8x as fast)
[21:36:30] <Valen> thats what I'm saying
[21:36:49] <Valen> 64mhz clock
[21:37:08] <Valen> what is your application that you need to do this?
[21:37:19] <sparrW> long string of LEDs, want a higher refresh rate
[21:37:36] <sparrW> or a bigger array of LEDs with the same refresh rate
[21:37:54] <sparrW> or more time for my non-led-driving code to run with the same led refresh rate
[21:38:05] <Valen> how many LEDs are you talking about?
[21:42:05] <Valen> if its just a fixed set of outputs perhaps look at making some kind of frame buffer
[21:55:38] <sparrW> a few hundred
[21:55:55] <sparrW> this device will BE the framebuffer :)
[22:06:18] <CapnKernel> inflex: October is my Melbourne month, so I'm in MEL now. Flying back to Shenzhen on Saturday.
[22:08:14] <CapnKernel> Anything I can do for you?
[22:14:24] <inflex> CapnKernel: nah, well, plenty I'd love people to do - but nothing realistic
[22:14:35] * inflex is just waiting for some $$$ to build up so he can buy an order of 100 LCs
[22:14:36] <inflex> LCDs
[22:52:20] <Valen> those teensy ones?
[23:07:31] <Valen> http://hackaday.com/2011/10/25/do-you-know-why-youre-supposed-to-use-decoupling-capacitors/ is kinda cool btw
[23:11:02] <inflex> Valen: erm, lemme show you
[23:11:15] <inflex> http://dxp.me/i/scc1-unfolded.jpg
[23:11:31] <Valen> yah teensy ones ;->
[23:11:44] <Valen> moq 100 is sucky
[23:11:55] <inflex> well, I need 100
[23:12:00] <inflex> I can get as low as 1 if I want
[23:12:30] <Valen> ahh
[23:12:59] <inflex> I suppose I could get away with an order of 20, but I'd be hurting due to the effective cost-per-unit after postage
[23:13:06] <inflex> not that I've got any money atm anyhow
[23:13:11] <inflex> just spent my last $4 on fuel
[23:13:27] <Valen> nasty
[23:13:35] <Valen> more book sales ftw?
[23:13:43] <inflex> yeah, I'm a tad shell-shocked atm because the last 3 weeks were really good
[23:13:47] <inflex> sales were coming in every day
[23:13:57] <Valen> rego due tomorrow
[23:13:59] <inflex> and I was able to pay out some bills
[23:14:12] <inflex> but now the bills are uptodate, the money has stopped
[23:14:25] <Valen> least the bills are done?
[23:14:57] * crazy_pete is glad he has little need to care
[23:16:44] <crazy_pete> but i am glad your bills are uptodate
[23:18:56] <inflex> Valen: until the end of this week
[23:19:05] <inflex> Valen: anyhow, I should stop bitching on IRC and just get some work done
[23:19:06] <Valen> :-<
[23:19:14] <Valen> helps with the sales some
[23:33:27] <CapnKernel> Anyone here know PostScript?
[23:37:52] <inflex> not real well
[23:39:19] <CapnKernel> I am messing around with barcodes. I'm using GNU barcode to generate the PostScript. That's all very well and good.
[23:39:46] <CapnKernel> I am trying to get the barcodes to line up exactly with my label paper. I need to be able to specify a translation and a scaling.
[23:40:15] <CapnKernel> I want the scale to happen relative to the translated point, not the original point.
[23:40:42] <CapnKernel> I'll get a trivial example to show what I mean.
[23:40:58] <inflex> yeah, I know what you're saying
[23:44:19] <CapnKernel> Trivial example:
http://paste.pocoo.org/show/498292/
[23:44:43] <CapnKernel> Save it as a .ps file
[23:45:00] <CapnKernel> Then play with the line that says "0 mm 0 mm translate 0 0 moveto 1 1 scale"
[23:45:22] <CapnKernel> In that file, the values are for the identity translation and scale
[23:46:39] <CapnKernel> How can I scale the square so the lower left corner of the square stays in the same position?>
[23:47:01] <inflex> you probably need to scale it first at the origin, then translate it
[23:47:25] <CapnKernel> I'll try.
