#robotics Logs

Sep 12 2014

00:04 rue_mohr2 or softwares
00:06 GargantuaSauce get one of your arms stacking blocks or something
00:07 rue_mohr2 ah arm control software
00:09 rue_mohr2 what software would a movie geek have?
00:14 GargantuaSauce if it were a movie it could play jenga
00:27 rue_mohr2 I dont think I want to play jenga against a program
00:27 rue_mohr2 I wrote a tic-tac-two program and the best you could ever do was to tie
00:28 rue_mohr2 it knew EVERY move of EVERY tictactoe game!
00:50 GargantuaSauce i think you will have more trouble producing a perfect jenga player
01:12 Hyratel rue_mohr2, jenga blocks are just irregular enough that "shuffling" by tumbling the stack and rebuilding randomises the Fit of each layer enough that it'd be effectively competitive
01:22 GargantuaSauce that is almost irrelevant compared to just the motion control involved in pulling a block without toppling the structure i think
01:24 Hyratel GargantuaSauce, did you see the megaJenga with CAT laoders?
01:24 GargantuaSauce no
01:25 Hyratel oh man, it's a treat to watch
01:26 Hyratel https://www.youtube.com/watch?v=DWc8dUl7Xfo
01:26 GargantuaSauce cool
01:26 GargantuaSauce not a fan of the video production but cool nonetheless
01:33 Hyratel still, it's an impressive demonstration of operator dexterity
01:34 Hyratel like, i've seen backhoe operators shave half an inch off a bed of gravel
01:38 GargantuaSauce yeah it's pretty impressive what some can do
01:38 GargantuaSauce the cat dealership here had a public demo day and i got to dick around with an excavator for a bit, that was fun
01:39 GargantuaSauce i was pretty clumsy though!
01:49 mrdata_ at a cat dealership?
01:49 mrdata_ what were they excavating?
01:50 lowtierinquiry GargantuaSauce: hey im anonnumberanon. what was that board you showed me the other day that was cheap and powerful? im going to talk about it in robotics club tomorrow
01:50 GargantuaSauce stm32f4discovery
01:50 lowtierinquiry not sure but think it was based on ARM and with a lot of digital io ports?
01:50 GargantuaSauce yes, cortex-m4f, around 100 ios
01:51 GargantuaSauce well more like 85 i guess
01:51 lowtierinquiry yeah thats a lot
01:52 lowtierinquiry for computer vision I would need to make it send data to a computer with a beefy gpu?
01:53 GargantuaSauce depends on what you want to do, and the desired framerate, and the resolution of the camera etc
01:53 GargantuaSauce a single board computer might suffice
01:54 lowtierinquiry so like a board with integrated graphics like HD3000 for example?
01:55 GargantuaSauce i was thinking a software implementation running on an arm soc
01:55 GargantuaSauce i wouldn't do gpu acceleration on intel, that would be silly
02:00 lowtierinquiry like the stm32 ?
02:00 lowtierinquiry im not sure if you call that a computer
02:01 GargantuaSauce no i mean something with an order of magnitude more power, something like you'd find in a phone
02:01 GargantuaSauce the one i've messed with most is the allwinner a10 on the cubieboard but there are other options
02:08 lowtierinquiry does it take a lot of power? it would be for an autonomous project with a chatge of about 20 minutes
02:09 lowtierinquiry i know question is too vast
02:09 lowtierinquiry lol
02:09 GargantuaSauce well the thing about computation on a robot is that even if you're wasting a bunch of power on it it's probably way less power than you're using for locomotion anyway
02:10 GargantuaSauce it'd be on the order of 10W tops, probably less
02:11 GargantuaSauce anyway i'd still consider doing minimal computation onboard and having wireless communications with a pc to do the heavy lifting, it's a pretty valid approach also
02:11 GargantuaSauce and allows for flexibility in development
02:12 GargantuaSauce getting video from point A to point B is kind of a pain though, and i say that as someone who is making a business out of doing just that
02:14 lowtierinquiry funny cause that was my idea as well. sending the video through wireless. but who knows how fast you can do so
02:14 GargantuaSauce the simplest way to do it might just be analog video
02:15 GargantuaSauce or perhaps a turnkey solution like a security cam with wifi
02:18 GargantuaSauce also i don't mean to be discouraging but at the high school level doing computer vision stuff might be a little out of scope
02:19 GargantuaSauce oh wait you're the capstone dude
02:20 GargantuaSauce well the point stands to a degree. hope your linear algebra is up to snuff
02:20 lowtierinquiry yeah i am him
02:21 lowtierinquiry yeah i got an A in Lenear Algebra I really liked it.
02:21 lowtierinquiry heh
02:23 lowtierinquiry good talk. we'll be voting on a project today.
02:23 lowtierinquiry then ill be listing our challenges and requirements
04:39 deshipu GargantuaSauce: thanks, I think I will try to loop them, I want to be able to reuse the servos in other projects if this fails
09:12 rue_mohr2 even security wireless tends to be 3 seconds lag
09:32 GargantuaSauce yeah low latency digital video is hard
09:34 rue_mohr2 I think its only hard if people insist on using hardware or software that buffers frames
09:34 rue_mohr2 er protocols
09:35 rue_mohr2 from what I can tell (iirc) a webcam to mencoder to a webbrowser over wifi ends up with over 100 frame buffers
09:35 rue_mohr2 every layer must buffer a frame or two
09:46 deshipu rue_mohr2: show me your board!
12:39 GargantuaSauce rue_mohr2: show me a digital video system that doesn't buffer frames
12:39 GargantuaSauce hint: they don't exist
12:40 GargantuaSauce even $40k studio cameras do it
12:50 chris_99 anyone played with lidar here out of interest, i just bought a cheap module of fleabay
12:52 GargantuaSauce no but i have plans to
12:52 GargantuaSauce what did you get
12:53 chris_99 it's one from a vac cleaner so it's called neato xv-11
12:53 deshipu "cheap" for a lidar is like $300?
12:53 chris_99 this was �60
12:53 GargantuaSauce oh yeah that on, cool
12:53 GargantuaSauce my experiments are gonna be vision based
12:53 chris_99 im thinking of looking into slam
12:53 chris_99 *SLAM
12:53 GargantuaSauce relevant to my interests
12:54 chris_99 :)
12:55 chris_99 i should read up on how my sensor actually measures depth, as i can think of a couple of ways i think
12:58 GargantuaSauce that xv11hacking wiki doesnt seem to have any actual info on its function
12:58 chris_99 mm
12:59 chris_99 i was thinking 1 way it could work is measuring pulse times
12:59 chris_99 and then isn't there the interferometer
12:59 chris_99 way
12:59 GargantuaSauce i would say it's more likely to be interferometry because time-of-flight requires ridiculously accurate timing measurement
12:59 chris_99 mmm
12:59 chris_99 i agree
13:00 chris_99 interferometer would be hard to DIY right?
13:00 GargantuaSauce kinda
13:02 GargantuaSauce it might also just measure parallax
13:02 GargantuaSauce that's how i would and will do it
13:02 chris_99 interest
13:02 chris_99 ing
13:03 chris_99 so that would require a image sensor?
13:03 GargantuaSauce well all it really needs is a line
13:03 GargantuaSauce and that potentially could just be two sensors in a line
13:04 chris_99 doesn't it require an array of photo detectors to measure the divergence?
13:04 GargantuaSauce well you can have two spatial samples with known sensitivity distributions right
13:04 chris_99 you mean look for the amplitude of it?
13:05 GargantuaSauce yes
13:05 chris_99 ah
13:05 chris_99 interesting
13:05 GargantuaSauce you'd need some reasonably fancy optics i guess
13:05 GargantuaSauce or could also just use a line sensor like you'd find in a scanner
13:06 GargantuaSauce i have one but couldn't make heads or tails of it
13:06 chris_99 ah darn
13:06 GargantuaSauce i imagine a 10 year old one would be much more approachable
13:06 GargantuaSauce what i plan on using is a camera and a laser line projector
13:07 chris_99 sounds like a good idea
13:07 GargantuaSauce no idea how quickly it can be swept before the rolling shutter becomes a real problem
13:08 deshipu getting the photos sent for developing and back can introduce some lag ;)
13:08 GargantuaSauce no man, onboard development lab
13:08 chris_99 lol
13:08 GargantuaSauce can get the latency down to 10s or so with some effort
13:10 deshipu realism aside, how cool would that be? :)
13:10 GargantuaSauce pretty cool until you leak a sodium hydroxide solution all over the floor
13:11 deshipu oh no, for efficiency you would have that in a high pressure tank
13:11 deshipu so it's not the floor, it's the ceiling
13:11 deshipu and walls
13:11 GargantuaSauce and eyes
13:11 GargantuaSauce woo i like this idea
13:11 deshipu the goggles, they do nothing!
18:57 -hobana.freenode.net:#robotics- *** Notice -- TS for #robotics changed from 1410562104 to 1164523368
18:57 hobana.freenode.net changed topic of #robotics to: Arduino controlled, 3d printed psycho robots! | http://tom-itx.ddns01.com:81/~webpage/index.php | happy hour at 2am GMT!
21:07 MrCurious i do not like this game
21:07 MrCurious this scotland succession thing looks to be getting very serious.... http://waterfordwhispersnews.com/2014/09/12/backtrack-on-yes-vote-as-buckfast-threatens-to-pull-distributation-in-scotland/