#robotics Logs

Sep 30 2012

00:00 rue_house as the people in the encoder channels tell me there is no computer powerfull enough to live encode video for a robot
00:00 katsmeow-afk use something like LM567's as demodulators
00:00 rue_house aren't they slow?
00:00 katsmeow-afk a couple Mhz
00:01 katsmeow-afk fine for 67Khz
00:01 rue_house huh
00:01 katsmeow-afk there's faster ones, for sure
00:01 rue_house 4046 > 567 ?
00:01 katsmeow-afk i didn't say use it on the rf stuff, just the audio demodulation
00:01 katsmeow-afk could also use it as the modulator, sure
00:01 rue_house if decoding?
00:02 katsmeow-afk 567 will demod bits and bytes, the DTMF demod chip is basically a dual 567
00:03 katsmeow-afk the 567 is an oooolllddeee chip, i'm sure there's betetr out there now, if you need "better"
00:03 rue_house the application note uses 7 567's :)
00:04 katsmeow-afk there's prolly fast enough video compressors, specially if you use a fpga core, buy why use up that power on a battery operated robot?
00:05 katsmeow-afk i'd just transmit as the camera outputs it, then munge it at the reciever end
00:05 katsmeow-afk you can same abttery power *per camera* if you alternate cameras on the feed
00:06 katsmeow-afk camera1 - camera2 -camera1 - camera2 , etc
00:06 katsmeow-afk best to sync the cameras and switch in Vinterval
00:08 katsmeow-afk i think, seriously, if you wanna minimise battery use, use a 8bit flash adc chip, feed memory, compare to previous memory, send only the difference between whatever is new and what you sent last ,, but i think you will be wasting time, because the small bouncy robot is never going to have cameras-on the same scene twice
00:10 katsmeow-afk if you want only 7bit video, you could use 8bit flash, drop the last bit, then send signal only when there's bit changes
00:11 katsmeow-afk it will look real grainey, but save transmitter battery
00:11 katsmeow-afk not by a lot
00:11 rue_house hmm
00:11 rue_house or transmitt it analog on ch3?
00:11 tsmeow-afk
00:12 rue_house we got point-to-point bluetooth working
00:12 rue_house took ~2 mins to tranfer a 3.5M file
00:12 katsmeow-afk you could still use digital methods to gate the analog , like if the camera is looking at essentially the same wall, stop sending
00:13 katsmeow-afk ouch
00:13 rue_house well its bluetooth
00:13 rue_house I thought that was pretty good
00:13 rue_house I see bluetooth as a short range control
00:14 rue_house wireless serial
00:14 katsmeow-afk "i told it to go north, and before i could tell it to stop at the end of the driveway, it was out of range, i have not seen it since"
00:15 rue_house we were both on desktops, aka, we didn't check range
00:15 wizzbrah what is the name for the method of computing 3D from a single camera via comparing adjacent frames while the camera is moving?
00:15 Triffid_Hunter wizzbrah: monoslam
00:15 Triffid_Hunter wizzbrah: youtube.com/activevision has some really interesting work on that
00:16 rue_house hi Triffid_Hunter
00:16 Triffid_Hunter hi :)
00:16 katsmeow-afk and the new Apple has excitng pics of applying that to maps ;-)
00:17 katsmeow-afk http://theamazingios6maps.tumblr.com/post/31933286987/oaklands-980-freeways-have-awesome-new-rock
00:17 katsmeow-afk http://theamazingios6maps.tumblr.com/post/31931200687/oh-no-galloping-gertie-is-back
00:17 katsmeow-afk don't they usually make airports flat ? : http://theamazingios6maps.tumblr.com/post/31926886562/ladies-and-gentlemen-prepare-for-some-turbulence
00:17 rue_house I have realized that humans see in depth layers, but so far I cant tell the resolution of differentiation of the layers
00:18 rue_house I'm studdying depth perception of trees to find out
00:18 katsmeow-afk it sucks, depth is the angle tween the eyes , or offset in the two images recieved, of each object
00:19 katsmeow-afk study the sterio camera shots of the boat bow i don't have any more
00:19 wizzbrah Triffid_Hunter https://www.youtube.com/watch?v=5VyLAH8BhF8
00:20 rue_house not from what I can tell
00:20 rue_house most of the vision is taken from one eye, which is chosen depending on the better view
00:20 rue_house most of the depth is worked out by sheer planes
00:21 rue_house which is what interests me
00:21 katsmeow-afk then it's based on what hides what when moved
00:21 katsmeow-afk and data on relative sizes
00:21 rue_house if shows how, a human can tell you what eye they are seeing from
00:21 katsmeow-afk car bigger than cat, so if the cat looks bigger, the car is far away
00:21 rue_house the answers are interesting when you randomly ask them
00:22 rue_house not til there is movement
00:22 katsmeow-afk my brain shut off, i lok sleepy
00:22 rue_house http://www.youtube.com/watch?v=laty3vXKRek
00:23 rue_house alot of depth perception is done with forknowledge and assumtions about the scene
00:23 rue_house in some cases are wrong
00:24 rue_house without access to see the plannar division, i jst assumptions
00:29 katsmeow-afk i need to pump from creek tomorrow, my water is getting low
00:42 Triffid_Hunter wizzbrah: that looks more useful for video compression than 3d reconstruction
00:50 katsmeow-afk i just tried to boot Tiggr, no luck, the lightning strike was fatal, fans come on and it blows smoke
01:13 rue_house is it the power supply thats blown?
01:41 rue_house so it looks like 50hp should do well for my truck
01:41 rue_house (electric)
01:41 rue_house so, numbers for a 300V, 50hp brushless motor
02:07 katsmeow-afk you need only 10-15hp on level gnd at 40mph , you need 100's climbing a steep hill
02:09 katsmeow-afk my vw beatle pulled ~210/230amps@36vdc/48vdc@35/40mph
02:10 katsmeow-afk that said, the tires, air resistance, and weight are bigger with your truck, so while 10hp was enough for me for casual town driving, you will need more, and a 350cuin 4bbl and automatic won't maintain 70mph on a steep hill with 1800lbs in the back
02:11 katsmeow-afk gnites
07:44 Modeuse hello
07:45 ace4016 hi
07:47 Modeuse how are you?
07:48 ace4016 doing alright
07:48 ace4016 and you?
07:49 Modeuse I'm okay
07:49 ace4016 cool
07:49 Modeuse XD
11:18 rue_bed kat, I'm switching it to a standard for the conversion
11:18 rue_bed so, 300V
13:13 katsmeow-afk have you weighed any motors lately?
13:25 rue_house I was gonna make a brushless, rememeber?
13:29 rue_house http://eds.dyndns.org/~ircjunk/images/servocurrent.jpg
13:30 rue_house - top trace at 5V/div
13:30 rue_house - bot trace at .2V/div (I had some pressure on the servo HS311 iirc)
13:30 rue_house (so .2A/div) (sorry, zero is out)
13:30 rue_house - time at 0.5ms/div
13:37 rue_shop4 M51660L
13:38 katsmeow-afk brushless have lower peak power density, and haveto be more cooled
13:39 katsmeow-afk if the magnets get hot, they lose field, and if too hot they lose it permanently
13:39 katsmeow-afk it's also possible to apply so much magnetic field to them, they lose field and even reverse magnetise
13:40 katsmeow-afk that's how they got magnetised in the first place, right?
13:47 tsmeow-afk ponders a way to make thinwall copper pipe into flat hollow motor/transformer wind
13:49 katsmeow-afk because then the cores run cooler, and the heat in the cooling liquid can be recovered/recycled
13:52 katsmeow-afk 3||E
13:53 izua_ o_
13:53 izua_ O
13:53 katsmeow-afk Picasso ascii art?
13:53 izua_ 3з!
13:54 izua_ i was just looking at it trying not to see goatse
13:54 izua_ also, i think there are different ways to cool a transformer.
13:55 katsmeow-afk several ways, i was just pondering
13:55 katsmeow-afk there are transformers wound with hollow wire <shrug>
13:56 katsmeow-afk there is/was a transmisson line in Ca strung with hollow wire
13:56 izua_ that's a fancy way of saying pipe
13:57 katsmeow-afk true
13:57 izua_ although, hollow wires might be more flexible
13:58 katsmeow-afk a few yrs back, someone made a superconducting motor by winding it with tubing and pumping refrigerants thru the hollow windings
13:58 rue_house if they are made square you can save space
13:58 rue_house al the gaps on the INSIDE of the wire
13:58 tsmeow-afk runs more wire inside the "wire"
13:59 rue_house ooo then you would get even MORE surface area
13:59 katsmeow-afk lol, run the secondary inside the primary
13:59 rue_house low leakage
13:59 rue_house high capacitive coupling
13:59 tsmeow-afk
14:01 katsmeow-afk i wonder if there is a point where making the copper clad on a pcb becomes too thick
14:01 izua_ /j #stm32
14:01 izua_ disregard.
14:02 katsmeow-afk "it's 1 inch thick copper on this .064 pcb!"
14:03 tsmeow-afk joins #disre
14:06 izua_ it's either/or like #kierkegaard
14:07 tsmeow-afk didn't read
14:11 katsmeow-afk afk to be outside doing things
15:12 wizzbrah Can I say something brutally honest here?
15:13 wizzbrah The NAO robot from france... that thing is is just not built for ergonomic motion http://www.youtube.com/watch?v=h548R3N49No
15:13 wizzbrah the NAO's hands are basically useless
15:13 wizzbrah It can't walk per se... but sort of shuffle
15:17 Monie I'm new to robotics, just joined the club at my university. I want to start out with a simple project, any recommendations?
15:20 chris_99 a line following dealio?
15:32 Monie alright
15:36 katsmeow-afk a dealio might be a big step for a beginner
15:38 chris_99 heh
15:42 katsmeow-afk there's been roughly one ferry crash into dock per day in Europe the last week, they could use a line follower to get to dock properly
15:44 chris_99 eek, that's rather bad
15:44 chris_99 i guess you'd also want some nice little algorithm that allows the ferries to talk to one and other
15:45 katsmeow-afk they aren't so concerned, one kept carrying passengers the next day till some gov offical shut them down for having a hole in the side of the ship
16:02 wizzbrah I see that my brutal honesty in regards to the NAO robot is going to be feverishly ignored by you
16:03 tsmeow-afk frantically agrees with
17:48 afro robotics?
17:48 afro sounds good
17:51 sw0rdfish hi afro :)
18:08 afro hi swordfish
18:20 rue_shop4 a given carb has two adjusts, high and low, the idle speed is too low, which gets adjusted?
18:22 Tom_itx low
18:22 Tom_itx or the butterfly stop
18:25 tsmeow-afk has a opinion poll: if i want a 1kw xformer for 60hz sine, from 100vdc to dual 25vac@20amp , should i stay with the MOT approach, or try abusing other forms of xformer co
18:29 katsmeow-afk <cough>
18:34 sw0rdfish heh
22:04 katsmeow-afk ...
22:28 sw0rdfish ... :p
22:34 katsmeow-afk oh
22:35 rue_house hmm
22:35 rue_house whats wrong with a mot?
22:35 rue_house there are lamp ballasts, but I dont think they handle as much power
22:36 wizzbrah if the NAO robot is going to be used for "AGI", then it needs completely re-engineered and designed
22:37 katsmeow-afk i was thinking using two mots, 1kw is a lot of power, even if i don't pull that much
22:38 katsmeow-afk i also wanna put the whole mess into a 3U rack space (minus the batteies, of course)
22:39 katsmeow-afk i can allocate 1/3 to battery charging, and 2/3 of it to making it back into 115vac
22:39 katsmeow-afk may end up being 50-50 tho
22:40 katsmeow-afk i just need the transformer for the ac peak above 110dc
22:41 katsmeow-afk ok?
22:43 tsmeow-afk still does not know the significance of "the caliope crashed to the gro
22:45 sw0rdfish hmmmmm
22:45 sw0rdfish I wonder if I can get lulu.com to print for me a .pdf ebook and send it to me
22:51 katsmeow-afk do you often wonder that?
22:59 katsmeow-afk i need an on-off switch on me
23:39 katsmeow-afk got Tiggr back up
23:43 katsmeow-afk i still dunno if the psu or the mobo is toast, but the hd survived