#robotics Logs

May 21 2013

00:04 theBear err, full of win that is, not homophobic racist or, well i spose i am disabled currently :)
00:05 theBear aww, us only :( i wanted to see where all the racist homophobes and other cripples were here
00:11 MrCurious seems i should NOT act surprised when a access point run off of a small usb wifi dongle has shit propigation and packet loss while operating in a congested 1,7,11 spectrum
00:12 GargantuaSauce this is a dongle plugged into an rpi too isnt it
00:12 GargantuaSauce which has a usb peripheral with drivers of questionable quality
00:13 theBear WOAH ! it's bright just after you notice you been wearing your sunnies indoors for the last 20 mins
00:14 MrCurious GargantuaSauce: spot on the money
00:14 MrCurious but in its final deployment, i may get a better wifi dongle with a bigger antenna
00:14 MrCurious though i only need 10 yards range
00:37 MrCurious and there is some drilling win
00:41 MrCurious wondering if i need to ground shield a 3 foot length of +5, G, tx, rx
00:42 GargantuaSauce might want to turn the serial lines into twisted pairs
00:43 GargantuaSauce and maybe add an extra capacitor on the power line if whatever it's running doesnt already have a big one
00:48 theBear kinda depends a lot on speed and cable stype and stuff, but if it's 5v or higher levels (0/5v data for example) and not crazy speeds, well, it takes a lot of noise to make a 0v look like a >2.5v, and likewise for 5v.... and twisted pairs aren't much good unless you differential and undifferential the signal either end
00:50 Triffid_Hunter GargantuaSauce: twisting random signal wires generally isn't particularly helpful.. you need to run it as a differential line for that to help. see RS422 which is basically the differential version of RS232
00:51 theBear and which can comfortably run say, 250kbps serial past racks of noisy 3phase gear and piles of associated poorly placed feed cables, easily 50meters without even a hint of a problem
00:51 MrCurious GargantuaSauce: used a pair of twisted pair
00:52 theBear and if someone guesses where i picked those particular numbers/example from, don't bother complicating my example with facts like it's not 100% rs422, i know, but it's a reasonable/valid imaginary example
00:53 MrCurious at 3 foot of length, the solid aluminium housing should be enough to shield
00:55 theBear i've been enjoying doing all kinds of silly things over cat5 (cos i've already got it, and in several cases it's already in place with 2 pairs just sitting idle!!!!) in recent times, and abusing/misusing salvaged coils and transformers... if you are the adventurous type and feel like 'wasting' a few hours doing tests that may get you nowhere different to when you started, albeit a little more in touch with some facts, you might experiment with self w
00:55 theBear ound or various common salvaged transformers for running a twisted pair, but 3 foot, it'd have to be damned fast and a HORRIBLE environment for things to go wrong
00:56 theBear at 'regular' kinda serial speeds and levels, you can run any crappy old idc skinny conductor ribbon cable way longer than that and not have issues
00:57 theBear back in the day i used to plug together what few random serial/rs232 cables i had way over 10meters and the 2400baud modem never seemed to care <grin>
00:58 theBear and there was at least 3-5 meters of that jumble made up of crappy beaten old idc/ribbon cables :)
00:58 theBear then again, these days even 'really slow' serial isn't usually THAT slow :)
00:58 theBear that was just the transition period where you couldn't QUITE read/type as fast as your modem could receive/send :)
00:59 theBear and if you downloaded a plaintext file breaking the 240character/second barrier was considered a good day :)
01:16 MrCurious the end is nigh
03:40 Jak_o_Shadows right. Motor is mounted to wheel. Unfortunately it's off center, so that's bad. Also bad is that it runs crazy fast.
03:41 theBear yep, 1 step forward, 2 steps back, that old chestnut :)
03:46 Tom_itx h
03:47 Jak_o_Shadows also bad is that i'm just using a dpdt switch, not a h-bridge, so I nly have on-off thing.
03:48 Jak_o_Shadows So I'm gonna run it on for a microsecond, then off lol.
03:48 theBear Tom_itx, lol
03:48 theBear w
04:05 Triffid_Hunter Jak_o_Shadows: this is what the gearbox is for
04:05 Triffid_Hunter Jak_o_Shadows: even with PWM it will have very little torque. your 'bot will likely not run at all on carpet
04:05 theBear heh, i know a dog whose bot runs like a train on carpet <grin>
04:33 Jak_o_Shadows Actually, it runs ok on tiles.
04:33 Jak_o_Shadows although, I didn't have much choice apart form a whole redesing
04:33 Jak_o_Shadows redsign
04:33 Jak_o_Shadows redesign
04:33 Jak_o_Shadows Although, a right-angle gearbox thing would be perfect really. Pity I don't have one.
04:34 Triffid_Hunter print one!
04:35 Jak_o_Shadows It's really really tempting actually
04:37 rue_house you cane make one easy
04:37 rue_house dont even need a lathe
04:37 rue_house drillpress helps
04:38 Jak_o_Shadows How would I do that? For future reference? Wouldn't I need to get the gears?
04:38 rue_house put a 1/4" tap in the drillpress and push a disk on a bearing into it, as the tap turns in threads itself around the disk
04:38 rue_house then you use threaded rod as the drive screw
04:39 Jak_o_Shadows Oh yeah, didn't think of that.
04:39 rue_house http://eds.dyndns.org/~ircjunk/tutorials/mech/p1010110.jpg
04:39 rue_house opps, not that one
04:40 Jak_o_Shadows haha.
04:40 rue_house http://eds.dyndns.org/~ircjunk/projects/lathe/p1040795.jpg
04:41 rue_house http://eds.dyndns.org/~ircjunk/projects/lathe/p1040789.jpg
04:41 rue_house I ued a lathe but I'v used a drillpress before
04:41 rue_house http://eds.dyndns.org/~ircjunk/projects/lathe/p1040788.jpg
04:43 Jak_o_Shadows cool
04:48 Jak_o_Shadows By sheer coincidence, the robot has a handy carry handle.
04:48 Jak_o_Shadows Also, the bloody wheel isn't staying attached to the main body
04:49 theBear hehehe, you gotta learn the simple art of purely aesthetic cleaning up after welding one day mr mohr
04:50 theBear hmmm, that is kinda a cool way to make a whatever you call that pulley/gear thinger
04:50 theBear what's the material ?
04:51 theBear err, stock, err, it's been a while, i done a lot more machining than talking to people about it :)
04:52 theBear hmm, first sip i'm not entirely sure how i feel about this beer, but i am entirely sure i like being tipped off that it was only 3/4 of the marked shelf price due to some labelling error :)
04:53 theBear and you know, a beer has to be pretty darned horrible and un-beer-like for me to rate it below the 'acceptable <> pretty good' scale that i use for beer :)
04:53 RyanS Beer is never good
04:54 theBear it is if you like your alcahol bubbly and with bonus water some of the time :)
04:55 theBear and at $3.75/litre, pfft, cheaper than buying bottled water <grin>
04:56 RyanS You could argue possibly beer is more environmentally friendly than bottled water... Perhaps
04:57 theBear hehe, fortunately i'm not that way inclined, but i can confirm that all things considered, i prefer beer to bottled water :)
04:57 theBear and soda water and mineral water... tonic water tho, that's a thinker
04:57 Triffid_Hunter tonic water is horrid to my tastebuds
04:59 Triffid_Hunter I wish I liked it.. it glows under UV lights
04:59 theBear mmm, that would put you in the majority according to my extensive polling over a large sample audience across a huge crossection of society and an unusually long period for this kind of research
04:59 RyanS You can't beat a nice strong cocktail
05:00 theBear heh, you know ! i used to love drinking it at 'discos', all the space cadets go crazy when they see one guy with a magical glowing drink in a sea of dark and shining teeth
05:00 theBear it's true, i've tried, even tried flogging one, it's tricky, they're so, liquid :)
05:00 theBear at the same time, nice, even horrible cocktails, don't really match my budget these days
05:01 Triffid_Hunter heh I used to go for double ouzo and red creaming soda.. looks like a "chick's" drink right up until you smell it ;)
05:01 theBear you sick bastard !
05:01 theBear i suppose i did say horrible cocktails tho
05:01 theBear a good buddy is a bit like that, one of his favourites is lemonade and black sambuca, horrible sticky licorice flavoured mess that it makes
05:01 theBear nice colour tho
05:02 Triffid_Hunter black sambuca is nice by itself, wouldn't adulterate it with anything
05:02 Triffid_Hunter prefer white though
05:03 theBear i suppose it would be if you liked the flavour of licorice, or whatever the ingredient is that makes them both taste horrible to me
05:04 Triffid_Hunter yeah liquorice is awesome, love it :)
05:04 theBear well, i guess, i'm pleased for you :)
05:07 theBear hmm, better get what's left of the drying indoors before the air goes all moist and un-dry-friendly again... not a bad yield, but suffice to say, i really miss the washing machine, more for the spin cycle than anything else
05:09 RyanS I have too much disposable income, so I have all the good stuff :)
05:09 RyanS It's good to see my pension is going somewhere useful
05:10 RyanS hmmmmm.. I wonder if this works http://www.machines4u.com.au/view/advert/Mazak-CNC-vertical-Mill-machine-centre/83940/
05:10 theBear really ? hmmm, i'm only just getting over the pre-full-pension debts and learning to budget again (no use budgeting when you've got a negative net income before food/drink), but, i don't see myself ending up with a surplus :)
05:10 theBear still, bears seem to get thirstier than normal people
05:10 Jak_o_Shadows I like licorice
05:11 theBear heh, what can i say ? you're a nice guy too, and i'm glad you can be made to smile by something so cheap and available :)
05:11 Jak_o_Shadows I've tried ouzo, but never in any large amount, or mixed with anything
05:12 theBear i'm not fond of it, the homemade stuff people from those kinda areas make seems to be more palatable
05:13 theBear i like simpler non-sticky liquor in general, vodka, gin, tequila, and even the brown whiskey variants as i get older
05:13 RyanS weird the last 10 messages popped out all of a sudden
05:20 theBear mmm, wasn't unusual a week or so ago, or in the dark old days of last century :)
05:28 RyanS are open source 3-D printers actually useful except as a toy?
05:31 theBear can't see why not, i don't know much of what commercial ones are used for, but i've seen a few demo/prototype product cases (often fully populated and 'working') travelling around with various sales reps over the years, and they aren't much different to what even a basic reprap can do with maybe a quick sand and once over after printing, depending on the plastic used of course (some reprap result pics i see are horribly bumpy and 'not right' looking)
05:32 theBear and those professionally/commercially made/printed things cost a FORTUNE, even when all they have to do is load up your artwork and hit 'the go button', god forbid they have to scale or modify it somehow !
05:34 RyanS But of course you would probably have to spend a real fortune to get a professional printer that is more capable?
05:34 RyanS Some of the printouts on commercial machines look uber
05:36 theBear even equally, i mean, i'm not exactly familiar with what is common or the full range of options, but everything i've ever seen/heard from small 'basic' models to big fancy serious ones that can make 'real mechanical parts' etc sounds kinda extortionate... then again i suppose 'basic' commercially made cnc gear seems to have inexplicable markup % too
05:36 theBear suppose margins are tight making such complex machines that aren't exactly needed/purchased en masse
05:39 RyanS hmm, I wonder if the DIY ones can print assembled gearboxes like you sometimes see? Although I think thats SLS
05:39 Jak_o_Shadows I doubt you could do assembled ones
05:39 theBear assembled gearboxes ? i suppose it's not impossible, but that's kinda a cool trick
05:42 RyanS A multi axis CNC machining centre would be better but,... A 3-D printer is $199,000 cheaper but I want to build model engineering stuff
05:44 theBear there's no denying that statment
05:47 RifRaf RyanS, how much will a cnc cost you?
05:48 RyanS idk, too much?
05:49 theBear RyanS, remind mewhich state/city you in ?
05:49 RifRaf well a 3d printer is mile 699, so plus 199 would be 898, but where di i buy a cnc machine for less than a grand?
05:50 theBear 'mile' ?
05:50 theBear oh, mine
05:50 RyanS melbourne
05:50 Jak_o_Shadows ONE OF US! ONE OF US!
05:50 RifRaf mile = like :) lol so glad you worked it out, i considered correcting but then decided not to
05:51 theBear hmmm.... i mighta had a suggestion in syd, but you wouldn't wanna even ask what something that size/weight would cost to get to another city, i'm not thinking of a small machine
05:51 RyanS less than $1000 cnc?
05:52 RifRaf sorry maybe i misread you
05:52 RifRaf i see the cheapest used starting about 20k
05:53 RifRaf unless you want one from the 80's
05:53 RifRaf so a 3d printer seems way cool
05:54 RifRaf if i can ,make parts as nice as the ones i am biulding it with will be happy
05:54 RyanS I just like metal creations
05:54 RifRaf you need a nase metal 3d printer
05:54 RifRaf nasa*
05:56 RyanS There was Dr Karl on TV and also a lot of others are getting overexcited about 3-D printing being "the biggest thing since the industrial revolution". And in things like the aerospace industry are using them for 3-D parts. Except they failed to mention a DMLS machine is half 1 million bucks
05:56 RyanS And have been around since the 80s
05:57 RyanS I think CNC subtractive machinery will be around for a loooong time yet
05:58 theBear they're both kinda cool things, but they ain't changing the world overnight
05:59 Jak_o_Shadows 3d Printing takes far less skill than machining
05:59 RyanS Not with a multitasking CNC.... As long as you can use the cam software
06:00 RyanS But there probably is more skill and knowing what tools to use and so forth
06:03 RyanS The Industrial Revolution was really a revolution in terms of the upheaval it caused.. 3-D printing is merely an evolution and a small one at the moment
11:17 zero_coder hello
11:17 zero_coder where can i start learning about robotcs?
11:17 zero_coder total newbie :)
12:22 sw0rdfish http://www.xbox.com/en-US/hub/reveal xbox 720 being revealed
17:23 GuShH RifRaf: any wireless modules to recommend?
17:24 GuShH I'm thinking wifi but I could use BT or something even simpler, I want to start making the house a bit smarter.
17:24 GuShH and not every node needs to be directly accessible, I could just have a central node dispatch messages instead.
17:25 GuShH 433 MHz uart transceivers are a bit expensive
23:32 MrCurious suddenly worked out a 10 ping ping sensor using a 328 is actually cake to do
23:32 MrCurious time for the lead to meet the copper!
23:33 MrCurious though progress will be much more substantial if i actually plug the iron in
23:33 theBear hehe, we all been there
23:42 GargantuaSauce GuShH: nrf24l01+
23:44 GargantuaSauce also http://www.ebay.ca/itm/290908894527
23:46 GuShH GargantuaSauce: any particular reason?
23:47 GargantuaSauce it does all the heavy lifting for you
23:47 GargantuaSauce and modules are stupidly cheap
23:47 GuShH it's pretty much the same I posted but cheaper in bulk
23:48 GuShH assembled differently but the same nontheless
23:48 GuShH GargantuaSauce: what's the actual typical range at 5v?
23:48 GuShH indoors, outdoors
23:48 GargantuaSauce for the nordic one or that serial piece of garbage?
23:48 GuShH quiscent seems low enough not to be a problem
23:49 GuShH the one you linked to
23:49 GargantuaSauce i havent tested mine yet, probably a couple hundred metres at most
23:50 GuShH overkill
23:50 GuShH actually my gate / garage system uses a 433MHz module... it's not particularly good in range but it must be the TXs
23:51 GuShH it could even be lowered on purpose
23:51 GargantuaSauce anyway http://www.ebay.ca/itm/121042000247 is better
23:51 GargantuaSauce bidirectional and does retransmission and checksumming and so on
23:52 GargantuaSauce and addressible and has selectable transmission power blah blah
23:52 GuShH the idea is to have child nodes communicate with a parent node which in turn provides communication through other ports
23:52 GargantuaSauce yeah these would be much better for that
23:54 GuShH well the former is a lot more modern than the latter
23:54 GargantuaSauce yeah 4 decades or so
23:55 GuShH some people would be surprised to know rolling-code garage systems are still being made and sold :/
23:55 GargantuaSauce also there are amplified ones available for like 12 bucks
23:55 GuShH no need for extra range
23:55 GargantuaSauce you never know!
23:55 GuShH it's to be used within the house and one or two nodes outside
23:55 GuShH heh "you can't have too much power!"
23:56 GargantuaSauce might be a good idea for the master one to be amplified
23:57 GuShH I think it's much cheaper and smarter to go this way instead of using wifi or bt on every node, just because the master can provide that as well but at a fraction of the cost
23:57 GuShH problem is, master goes... they all go (fallback to autonomous mode)
23:58 GuShH must be a typo "power consumption is 400mA in power down mode" heh uA certainly
23:58 GargantuaSauce yeah wifi is super expensive, both computationally and financially
23:59 GargantuaSauce and bluetooth straight up would not work
23:59 GuShH I can provide it with an old x86 box, at the expense of power drw
23:59 GuShH draw
23:59 GargantuaSauce and every client?
23:59 GuShH as the master
23:59 GuShH "server"