#robotics Logs

Mar 03 2014

00:19 rue_more I recommend this video for borred people
08:51 gushhtab Brobotics
08:51 gushhtab Always so quiet
08:55 aemquo :(
08:55 aemquo gushhtab, Up to much?
09:00 gushhtab No
19:03 dswain sup
19:03 ace4016 ahoy
19:03 dswain lunatecs is the best
19:04 dswain amiright
19:04 ace4016 what's lunatecs?
19:04 dswain its the best robotics team
19:04 ace4016 ah...k
19:04 dswain what team are you on
19:06 ace4016 no team
19:06 ace4016 not everyone here does things like FIRST
19:06 dswain ah
19:06 dswain well first
19:06 dswain is awesome
19:06 ace4016 infact, i'm too old and can't join FIRST as a participant due to my career field
19:07 dswain well that suxx
19:07 ace4016 iirc engineers can't join FIRST :P
19:07 ace4016 they can only be mentors
19:07 dswain yeah anyone over 18 is a mentor
19:07 dswain you cant be on drive team if youre over 18
19:09 ace4016 so i'm guessing you're in highschool then?
19:09 dswain yeah
19:09 dswain sophmore
20:34 robotustra_ evening
20:36 MrCurious yes it is
20:36 MrCurious has Putin just pulled off the Crimea of the century
20:41 robotustra_ ?
20:41 robotustra_ is it a question?
20:41 armyofevilrobots haw.
20:41 robotustra_ I don't follow
20:41 MrCurious crime of the century
20:41 MrCurious crimea of the century
20:41 robotustra_ http://www.wired.com/images_blogs/dangerroom/2011/10/AI-Weapons-3Oct2011REL-VED01833-STILL-020.jpg
20:42 robotustra_ Crym was a russian territory from the time of Tsar Ivan Grozny
20:42 robotustra_ many many years ago
20:43 robotustra_ so I don't really care, it's just internal slavic war
20:44 robotustra_ some douzen of clanes fight against each other.
20:44 MrCurious so far, doesnt seem like a war
20:44 robotustra_ yes, just
20:44 MrCurious russia marched in, calmly, took up possitions, then said you are out numbered, be calm, put down guns, and welcom new overlords
20:44 robotustra_ огые сщтакщтефешщт
20:44 robotustra_ just confrontation
20:45 MrCurious i suspect for the average vlad on teh street, there will be very little differencec
20:45 robotustra_ russian navy are there
20:45 MrCurious yeah, like russia willl give up its ONLY warm water port
20:45 robotustra_ yep
20:45 MrCurious not gonna happen
20:45 robotustra_ that's why I don't care
20:46 MrCurious i dont care either. just liked the pun
20:46 robotustra_ one mafia change another, simple people will not notice big difference
20:46 MrCurious putin will probably put the old crook who was there back in control
20:46 robotustra_ there is no old crook
20:46 robotustra_ that's the problem
20:47 MrCurious thought old crook fled to russia
20:47 robotustra_ he is a political impotent
20:47 robotustra_ putin will not do this
20:47 robotustra_ he should find better replacement
20:48 robotustra_ yanukovich will not fly any more
20:48 MrCurious wonder how russia will dispose of him
20:49 robotustra_ ukriane is a conglomeration of territories
20:49 robotustra_ I don't care, he stole enough of money to buy a small island
20:51 MrCurious i had read he stole so much money tht it left the country budget non viable
20:51 MrCurious would think that rulle would be in Dictator 101...
20:52 robotustra_ I think that he is not only who stole money
20:57 robotustra_ I just finished to draw approximate block diagram of robot communication
20:57 robotustra_ Now I more less imagine what blocks I will have in the robot
21:01 MrCurious looks like hackedgdgets.com didnt pay their hosting bill
21:09 rue_more they fired bill
21:13 orlock bill?
21:24 rue_more <MrCurious> looks like hackedgdgets.com didnt pay their hosting bill
21:36 MrCurious and another laptop lid cam salvaged
21:41 orlock i have a few of them too
21:41 orlock need a rasberry pi to hook the mup
21:43 GargantuaSauce have fun getting multiple usb cameras working with the rpi
21:45 orlock GargantuaSauce: power?
21:45 GargantuaSauce bandwidth
21:46 MrCurious you can do multiple... just not at the same time aat any appreciable frame rate
21:46 orlock yeah, this would be with motion
21:47 orlock so not streaming as such
21:47 GargantuaSauce i mean usb bandwidth
21:48 GargantuaSauce you'll certainly need to be pulling video from them in order to detect motion, though i guess a couple frames per second from each would be feasible
21:48 GargantuaSauce will not be straightforward in any case
21:49 GargantuaSauce even at 320x240x15 i've had trouble getting two running at once unless it's using separate usb root hubs for each
21:49 orlock with USB 1.1?
21:50 GargantuaSauce i believe they're usb 2 devices but am not sure
21:50 orlock last time i played a lot with cameras was 13 years or so ago, and i was using a PCI tuner card
21:50 GargantuaSauce there are very strict limitations on how much bandwidth can be allocated for isochronous transfers over usb
21:51 GargantuaSauce personally i think the best way to go is find some cheap DV cameras on ebay and use firewire, but that requires a more fancy computer than a soc obviously
21:51 GargantuaSauce i am going to try cellphone cameras with a parallel interface with either the a10 (cubieboard) or the stm32f4 sometime in the near future
21:53 GargantuaSauce but from what i have seen usb cameras are pretty awful in general
21:53 orlock yeah, it all depends on how much you want to spend
21:53 GargantuaSauce even the fancy $150 webcams seem to suffer from the same issues as the $4 ones
21:54 orlock i was using a $90 webcam, it was nice
21:54 orlock adjustable exposure timing
21:54 orlock but a lot of it comes down to the sensors as well
21:54 MrCurious the ps2 eye cam is a weapon of choice....
21:54 orlock and specs vs quality
21:55 MrCurious i think its 60fps at 640x480
21:55 MrCurious or was it 120
21:56 orlock 60Hz, 120Hz at 320x240
21:57 MrCurious http://en.wikipedia.org/wiki/PlayStation_Eye
21:57 MrCurious 60hz @640
21:57 MrCurious 120 @ 320
21:58 orlock Sometimes you want lower frame rates though
21:58 orlock longer exposure per frame
21:58 MrCurious slower is always an option
21:58 orlock some webcams will do 30 second exposures
21:58 MrCurious but for robotics... fast is better
21:58 orlock not always - some webcams dont support the variable exposure
21:58 MrCurious minimizes motion jitter
21:58 orlock All depends on what you are doing
21:58 MrCurious do it in software :)
22:00 orlock real time feedback for a control loop to compensate for mechanical imperfections
22:00 orlock i think the fastest the control software even bothers to check is .5s
22:00 rue_shop2 drat, I wanted to use fets for the buck converter on my new power supply, but all the fet drivers I'v set myself up for are for low side driving
22:01 GargantuaSauce hehe
22:01 GargantuaSauce i distinctly recall you deriding the notion of even using fets on the high side :V
22:02 rue_shop2 the damn IGBT's I got ... combine the worst of the features I want
22:02 orlock hoping to be giften a rasberry pi for my birthday
22:03 rue_shop2 my gives orlock a raspberry pie with whipping cream
22:03 rue_shop2 huh
22:03 rue_shop2 I'm broken
22:03 e_shop2 gives orlock a raspberry pie with whipping c
22:03 rue_shop2 remember to share!
22:04 e_shop2 thinks about the damned buck conve
22:04 rue_shop2 lm2575
22:09 rue_shop2 thought i just permanently neutered my mouse, its ball went rolling off
22:09 rue_shop2 found it tho, all fixed
22:09 rue_shop2 lm2575 uses a PNP
22:09 e_shop2 goes back to trying to avoid dro
22:13 orlock you still use mice with physical balls?
22:13 orlock i havent used one of those in 15 years or something
22:19 rue_shop2 I scrapped optical mice right away, they jitter and creep
22:19 rue_shop2 I dont like that
22:19 rue_shop2 and I like to be able to pick a mouse up 1/4" and move it over without it tracking the motion
22:21 orlock i need to solder a new cord onto my mouse
22:21 orlock its intermittently losing connection
22:21 rue_shop2 just shorten the mouse end in more?
22:21 rue_shop2 when you do it, add a relief spring
22:21 rue_shop2 like a proper cord :)
22:21 orlock yeah - not sure where the fracture is
22:22 rue_shop2 right at the exit of the mouse
22:22 rue_shop2 where you keep crunching it up against your cup
22:22 orlock the cord already has mesh braiding all around it
22:22 rue_shop2 audiophile cord?
22:22 orlock nah - just expensive, old mouse
22:23 rue_shop2 also, funny enough, the last optical mouse I tried had only 2/3 the resolution of my good ball mouse
22:23 rue_shop2 "fff this!"
22:23 rue_shop2 ok this is an interesting problem
22:23 rue_shop2 ah
22:24 orlock mines a logitech G9
22:24 e_shop2 thinks
22:24 orlock adjustable weights and grip/casing
22:24 orlock programmable, etc etc
22:24 orlock you can turn the croll wheel detents on or off
22:25 rue_shop2 coool
22:25 rue_shop2 so, I either need a fet or a PNP
22:25 orlock flick the wheel and it spiiiiins
22:26 rue_shop2 its a 5A output buck converter
22:26 rue_shop2 wonder what P channel fets I have
22:26 rue_shop2 tho all P channel suck
22:27 rue_shop2 tho at 100k-300khz a PNP is gonna dissipate less drive power
22:27 rue_shop2 eee gad, i have a huge box of aluminum filings i been packing around for years to neutralize ferric chloride, ... which i dont even use anymore
22:29 rue_shop2 irf 9630
22:30 rue_shop2 irf 9530
22:32 rue_shop2 irf 9610
22:33 rue_shop2 what we got
22:33 rue_shop2 9630 at .8 ohms
22:34 rue_shop2 9530 at .3 ohms
22:34 rue_shop2 9610 at 3 ohms
22:35 e_shop2 throws out the
22:35 rue_shop2 root@freebee5:/tmp# ohm -r 0.8 -i 5
22:35 rue_shop2 Wattage is: 20.000000
22:35 rue_shop2 Current is: 5.000000
22:35 rue_shop2 Voltage is: 4.000000
22:35 rue_shop2 Resistance is : 0.800000
22:35 rue_shop2 :/
22:36 rue_shop2 root@freebee5:/tmp# ohm -r 0.3 -i 5
22:36 rue_shop2 Wattage is: 7.500000
22:36 rue_shop2 Current is: 5.000000
22:36 rue_shop2 Voltage is: 1.500000
22:36 rue_shop2 Resistance is : 0.300000
22:36 rue_shop2 bipolar would be from 3.5 to 10w
22:37 rue_shop2 I have dips that are .035R, which is like 1W, I thought that was bad
22:37 e_shop2 th
22:37 lock is disappoint that ohm is not available via
22:37 GargantuaSauce doesn't FeCl3 react quite....vigorously with aluminium?
22:38 rue_shop2 I think I'm gonna end up with lots of isolated dc-dc converters
22:38 rue_shop2 GargantuaSauce, it precipitates the copper out of spent fecl
22:38 rue_shop2 you get salt water and metal precipitate
22:39 rue_shop2 both of which can be disposed of easier
22:39 rue_shop2 ok, lets set a goal
22:39 rue_shop2 5A
22:39 rue_shop2 .5W
22:39 rue_shop2 root@freebee5:/tmp# ohm -i 5 -p 0.5
22:39 rue_shop2 Wattage is: 0.500000
22:39 rue_shop2 Current is: 5.000000
22:39 rue_shop2 Voltage is: 0.100000
22:39 rue_shop2 Resistance is : 0.020000
22:40 rue_shop2 that should be easy
22:40 rue_shop2 20mR
22:40 rue_shop2 so I need isolated 9V for the current amp, and 10V isolated for an N channel fet driver
22:41 rue_shop2 then i need to cough up a high side fet driver
22:41 rue_shop2 oh
22:41 rue_shop2 unless I put the switching logic off the bulk+ rail and makeit think its a - voltage reguator
22:42 rue_shop2 head hurts
22:42 e_shop2 d
22:44 rue_shop2 no, thats worse
22:44 rue_shop2 I'd have to put it on the output rail,
22:45 rue_shop2 the P channel fet in the dips I have
22:46 orlock Hmm. Hard rubbush time coming up
22:46 rue_shop2 P channel is 35mR, but can only take 30V
22:46 rue_shop2 so it would blow as soon as it let go
22:49 rue_shop2 hmm
22:49 rue_shop2 just the fet driver for this is gonna be a mess
22:51 rue_shop2 if I parallel 15 9530...
22:51 GargantuaSauce lol
22:52 rue_shop2 I would have enough gate capacitance to kick the ripple out of anything
22:52 rue_shop2 maybe I have a really good PNP
22:52 rue_shop2 unless
22:52 rue_shop2 *sigh*
22:52 rue_shop2 I buy fets just for this project
22:56 rue_shop2 price is getting higher for this new bench supply
23:07 rue_shop2 http://www.aliexpress.com/item/sub65p04-15-65p04-to-263-aerotron-field-effect-transistor/1524877788.html
23:08 rue_shop2 hmm, cheap USED
23:11 GargantuaSauce not sure i'd ever trust used fets
23:14 rue_shop2 its funny, I'd use some in a heartbeat if thye were from my shop
23:15 rue_shop2 but do I trust used stuff from anyone else?
23:15 rue_shop2 maybe not if I'm paying for it...
23:16 orlock its "used" not "scorched" "seared" "blackened"
23:16 rue_shop2 I visualize kids scaping transistors off motherboard over a fire...
23:16 rue_shop2 and the thing is, they sell them for almost the same price as they are new
23:17 rue_shop2 RLY?!
23:17 rue_shop2 yea
23:17 rue_shop2 hey, its you
23:17 rue_shop2 yea how you doing
23:17 rue_shop2 I'm good, you?
23:17 rue_shop2 I'm ok
23:17 rue_shop2 where you been
23:17 rue_shop2 sleeping
23:17 rue_shop2 ok...
23:22 rue_shop2 yup, I think your gonna have to sort thu your PNP transistors
23:22 rue_shop2 damn
23:23 GargantuaSauce it's finally happened
23:23 GargantuaSauce he's cracked
23:23 GargantuaSauce we all expected it to happen, but so soon?
23:23 rue_shop2 cause even if you get the P channel fet, you will need to hang a driver under the + rail, and them make a level shifter to get to it
23:23 rue_shop2 but I can shift that signal with just resistors
23:23 rue_shop2 you could....
23:24 rue_shop2 should I buy the fets?
23:24 rue_shop2 should you put a financial cap on this project?
23:24 GargantuaSauce you can probably get better ones that are new for a better price
23:24 rue_shop2 I have one
23:24 rue_shop2 which is?
23:25 rue_shop2 well, by the time I'v hit the price of a new bench supply that can do all this stuff, I'v hit the cap
23:25 rue_shop2 but... you.... .... you.... nevermind....
23:25 rue_shop2 see? I win
23:25 rue_shop2 you cant spend $10 on china crap every week or you'll go broke
23:25 orlock i need to do something like turn on my bench supply
23:26 rue_shop2 I dont EVERY week
23:26 orlock and clean off all the junk on my bench so i have somewhere to put it
23:26 rue_shop2 use a PNP
23:26 rue_shop2 I dont want to
23:26 rue_shop2 maybe TRY it, THEN see if its not what you want to do
23:26 orlock i found a tiny black and white CRT on the side of the road that takes 13V of all things
23:26 rue_shop2 orlock, cool!
23:26 rue_shop2 but a pnp will throw too much power
23:26 orlock some sort of security monitor thingy
23:27 rue_shop2 you might have a good one
23:27 GargantuaSauce sounds like it's time for a diy oscilloscope
23:27 rue_shop2 orlock, they exist
23:27 GargantuaSauce or just a vector display
23:27 rue_shop2 GargantuaSauce, he wants to make his bench supply a signal genorator too....
23:27 orlock GargantuaSauce: already got a CRO and even a DSO
23:27 rue_shop2 I'm willing to forgo that feature...
23:27 rue_shop2 but you want to fit it in
23:28 rue_shop2 well yea, whats wrong with that?
23:28 GargantuaSauce orlock: i'm thinking less useful tool and more cool thing to dick around with
23:28 rue_shop2 your overloading the DESIGN of your project
23:28 rue_shop2 pff
23:28 rue_shop2 *I win* :P
23:28 GargantuaSauce could you two use separate accounts? this is disconcerting as hell
23:28 orlock oh, since its hard rubbish collection around this area - old TV's everywhere
23:29 GargantuaSauce unless this is really just rue who has lost his shit
23:29 rue_shop2 orlock, HOT transistors ;)
23:29 orlock outside one house, theres about 6 or 7 tubes - the plastic shell has been removed
23:29 rue_shop2 multisync monitors use a few good fets too
23:29 orlock and a few more intact TV's - its odd, pretty much ever second house normally has a TV, the tubes get smashed sometimes
23:30 orlock but i have never seen the cases stripped off before
23:30 rue_shop2 dude, time...
23:30 rue_shop2 EEEK, I gotta go make supper and stuff, see yall later
23:31 rue_more I dont know what to make for supper
23:32 rue_more I'll make you supper
23:32 rue_more what you gonna make?
23:32 rue_more what you want?
23:32 rue_more I dont know
23:32 rue_more how about spagetti
23:33 rue_more ok