#robotics Logs

Dec 13 2011

00:01 rue_house I JUST built that
00:02 rue_house :) thats how good I am :)
00:03 zhanx rue is bragging
00:03 rue_house now if I could only put togethor a 12' mecha and a house in that timeframe I'd be set
00:03 zhanx i would too if i wasn't high on pain meds
00:03 zhanx yep
00:05 rue_house I dont think he's into it
00:07 rue_house 6:43 to 9:43-ish
00:07 rue_house 3 hrs to design it, I'm waaay tooo pickey
00:07 rue_house well and build it
00:07 zhanx well grab a tiny avr and make it sweep your floor
00:08 zhanx couple of ir walls and done
00:08 rue_house :)
00:08 rue_house sensors are extra
00:17 zhanx like 2 bucks
00:17 zhanx wait 5 and you get shorted one :P
02:01 zhanx rue_house: still up?
08:58 rue_house na, but I'm awake now
09:30 rue_house http://eds.dyndns.org/~ircjunk/robots/flatbot/p1030677.jpg
09:31 rue_house I shoudl peel and ebay it
10:24 diffract| hi
10:24 diffract| how do i assign axes to joints?
10:24 diffract| i know X points to the next link
10:24 diffract| then how do i choose Z?
11:13 RustyCage hello
11:13 RustyCage I have a question regarding the use of a gyro/servo combination
11:13 theBear well go on then
11:14 RustyCage I am a land surveyor, and I am attempting to build a device to allow me to drive an atv up and down the side of a levee system, while keeping the surveying pole perpendicular to the ground at all times
11:15 RustyCage as you can imagine if I just drove it with the pole in a fixed position, I would be getting bad data because of the angle
11:15 theBear hmmmm.... unless it's gonna be ridiculously powerful, or a stupidly lightweight pole, yer gonna wanna drive real slow
11:15 theBear or does it only gotta be right when you stop ?
11:15 RustyCage thats what I was wondering
11:15 RustyCage i would like it to work while driving
11:15 RustyCage I would be needing a very powerful unit
11:15 theBear just consider doing it manually, from the base of the pole, you need a LOTTA torque to keep that thing straight
11:16 theBear probably double the strength of a strong human, at least
11:16 RustyCage the pole itself is very light (carbon fiber)
11:16 theBear then i suppose you got leverage, ooh, and you need 2 axis... jeez
11:16 charolastra call a tank manufacturer; they've figured out how to always hold the gun horizontaly ;)
11:16 RustyCage but the gps unit on top weighs a few pounds
11:17 theBear few pounds ? gps on top ? jeez, surveying has gone crazy the last few years
11:17 theBear wtf use is a gps to a surveyor ? even a mil grade one isn't that accurate
11:17 RustyCage I can usually get within .1' consistently
11:17 theBear with a gps !?!?!?!?!
11:18 RustyCage its a specialized surveying unit
11:18 theBear oh, foot, but stil
11:18 theBear how long does the pole gotta be ?
11:18 theBear absolute minimum
11:18 RustyCage I had planned on only driving directly across the levee and not down the side, to eliminate the need for two axis
11:18 RustyCage it really doesnt have to be a certain length
11:19 RustyCage by down the side I mean driving the length of the levee horizontally
11:19 RustyCage I plan to just do cross sections
11:19 theBear hmmm... so you put it on the roof (i assume you want some height) ... does it need to clear both ends of the vehicle horizontally when the vehicle is at say, 45degrees ? if you can keep it short it's a lot easier.... if you can lose the pole and maybe use some kinda wheel i imagine even easier
11:19 theBear oh sideways
11:19 theBear same questions still apply
11:20 RustyCage These are things im trying to decide
11:20 charolastra i'd like to see that vehicle that drives on 45° inclination. do you own a tank? ;)
11:20 theBear you good with this kinda stuff ? know what a linear actuator is, how a solenoid works ? etc etc
11:20 RustyCage the vehicle Ill be using would be a polaris ranger
11:20 RustyCage a six wheel atv
11:21 theBear charolastra, a lot of jeep/4wd things can just barely do 45 in at least one direction err, not-sideways
11:21 RustyCage actually Im a newb when it comes to robotics, but I do understand what a solenoid is
11:21 charolastra yeah, under ideal test conditions
11:21 RustyCage youve lost me on linear actuator though
11:22 theBear charolastra, nah, i've been in ones my age going down forwards without rolling.... youcould try to stop, but the tyres wouldn't do it
11:22 RustyCage I dont suppose there is a self contained unit that can keep something at a specific angle?
11:22 theBear probably, but it'd cost a fortune
11:22 RustyCage ouch
11:22 RustyCage so I can build one for... less than a fortune?
11:22 theBear ooooh, you could do it old fashioned style, pendulum
11:22 theBear maybe damped
11:23 RustyCage I actually have a pendulum style setup that we already built
11:23 charolastra say, how heavy can that vehicle carry?
11:23 theBear well, i could build one for less than a fortune, but i've got a lot of experience in these areas... you don't sound stupid, you've got a good chance
11:23 theBear i suppose... an assisted pendulum would be much less power-hungry
11:23 RustyCage ok tell you what, Ill go snap a picture of what we have, you might find it interesting
11:23 RustyCage have a minute?
11:24 theBear who knows
11:24 theBear i gotta have a beer and a smoke, but i'll be back before bedtime
11:24 theBear there will be others to take my place tho
11:24 RustyCage cool
11:24 RustyCage brb
11:25 charolastra can't you do it passivly? like a pendulum with a very heavy counterweight, suspendet in oil
11:25 theBear it's gotta be damped but quick, i think assisted pendulum is the trick
11:26 theBear even just assisted damping
11:29 charolastra ideally, yes; but there is so much to do; find a robust level sensor, find the right actuators, programm the PID loop, ....
11:29 charolastra with a weight suspended in liquid you could calculate the required viscosity and be done :)
11:30 theBear but i suspect it needs a variable viscosity to do the job
11:31 theBear it might drive over a rock, need to jump quickly, stabilise, then jump back and stabilise.... a pure damper can't do that....
11:31 theBear it's not like a shock with up and down... i suppose you can do like a multistage shock so hard/fast movement is adjustable damping vs soft/slow, but stilll, sounds much more complicated than a micro to me, but i'm less of a mechanical master
11:38 RustyCage ok back
11:38 Steffanx front
11:39 RustyCage im going to upload some pics real quick
11:40 theBear i thought thats where you went to do
12:17 RustyCage http://i1089.photobucket.com/albums/i345/ablackholesun/100_0574.jpg
12:17 RustyCage funny you mentioned a tank.. this is pretty close
12:18 RustyCage this vehicle is actually the one we had the pendulum set up on
12:18 RustyCage recently they removed the pendulum and I couldnt find it to take a picture but I can draw one
12:18 RustyCage this second one is the vehicle we are currently trying to outfit
12:18 RustyCage http://i1089.photobucket.com/albums/i345/ablackholesun/100_0576.jpg
12:22 RustyCage heres a basic drawing of the pendulum unit that we had fitted onto the argo (tank looking unit)
12:22 RustyCage http://i1089.photobucket.com/albums/i345/ablackholesun/pendulum.png
12:23 RustyCage there was a large weight on the bottom in a trough and the GPS unit is mounted on top
12:23 RustyCage we kind of scrapped the idea because on its own it just wasnt holding the unit in place securely enough to get solid readings
12:26 charolastra did you try damping it?
12:32 eliotn hello
12:32 eliotn anyone do the ratslife competition?
12:33 eliotn :)
12:40 eliotn what do people talk about here?
12:44 RustyCage what do you mean by damping?
12:44 eliotn dampening the forces?
12:46 charolastra it looks like the pendulum is freely swinging
12:47 charolastra but i give up, i can't find the right searchwords but i know that tank barrels where once mechaniclay stabilize, maby you have better luck searching
19:04 rue_house http://eds.dyndns.org/~ircjunk/robots/flatbot/p1030678.jpg
19:05 rue_house 14cmx14cm robot platform for sale, no need for motor drivers, comes with 6V battery pack (4xAA)
19:05 Tom_itx how do you erase partitions in linux?
19:05 Tom_itx to ensure a drive is wiped clean
19:05 orlok use dd instead
19:06 orlok if you want to actually wipe the disk
19:06 Tom_itx this says it has an extended dos partition with logical drives but it won't let me delete them with fdisk
19:06 orlok dd if=/dev/urandom of=/dev/diskname
19:06 Tom_itx does that take a while?
19:07 rue_house yes
19:07 orlok depends on the disk size
19:07 Tom_itx right
19:07 orlok oh, bs=1M should speed it up
19:07 rue_house you can do cat /dev/zero > /dev/diskname which will take slighyly less time,
19:08 Tom_itx i'm gonna try something else first
19:08 Tom_itx if it doesn't get it i'll ask again
19:14 Tom_itx rue_house how many of those do you have ready to go?
19:17 rue_house right now
19:17 rue_house 0.8
19:17 rue_house I need to peel it
19:19 Tom_itx i need a newer tools disk
19:19 Tom_itx this one won't boot from a sata dvd
19:19 Tom_itx wrong dvd drivers
19:20 Tom_itx i'm always a bit nervous when ghosting 2 identical drives
19:27 zhanx Tom_itx, what sizes should i get for pcb drilling ?
19:29 Tom_itx if you want an assortment get the drillset1 from velleman
19:29 Tom_itx cheap but a variety
19:29 Tom_itx get 2
19:29 Tom_itx they're cheap
19:30 zhanx got a link?
19:30 zhanx i was looking at this
19:30 zhanx http://drillbitsunlimited.com/50-Piece-Solid-Carbide-Micro-Drill-Bit-Set-S3A-P2022287.aspx
19:30 Tom_itx http://www.amazon.com/dp/B003U6LZO6/ref=asc_df_B003U6LZO61813985?smid=ADWMM0Z727MRO&tag=dealtmp333248-20&linkCode=asn&creative=395105&creativeASIN=B003U6LZO6
19:31 Tom_itx these aren't carbide
19:31 Tom_itx a range from a #65 to a #75 would probably do
19:32 zhanx http://drillbitsunlimited.com/50-Piece-Solid-Carbide-Drill-Bit-Set-56-80-D7-P2027542.aspx
19:32 zhanx covers the whole range
19:33 Tom_itx you'd never use an 80
19:33 zhanx yea 80 looks big
19:33 Tom_itx .0135"
19:33 Tom_itx i have one that's not a stepped shank
19:33 Tom_itx really easy to loose
19:34 Tom_itx looks like you get 2 or 3 of each in that set
19:34 Tom_itx probably not a bad deal
19:34 Tom_itx just remember carbide doesn't flex
19:35 zhanx true
19:36 zhanx that should work as a starter set for me
21:13 thylon What kind of batteries does this use? http://forkliftcompare.com/specs.php?pid=108551
21:13 thylon And can we scale them down for robotics?
21:20 thylon http://i21.geccdn.net/site/images/large_wco/242047_8wco.gif
21:21 Tobias| http://www.crown.com/ncgi-bin/brochure_request.pl?sent=Parts
21:21 Tobias| :p
21:21 Paradoxial thylon: You'd probably have to purchase a model report
21:21 Tobias| Seems like the easiest way to figure it out
21:22 Tobias| Should identify the range of batteries used by that product line
21:22 Paradoxial But chances are, the batteries can be scaled down for robotics
21:22 Paradoxial Depending on the size of your robot of course
21:23 zhanx !assist arm
21:24 zhanx !assist robot arm
21:24 tobbor Possibly http://eds.dyndns.org/~ircjunk/robot arm
21:24 thylon Paradoxial http://www.greenbatteries.com/d5737.html
21:24 zhanx mmm
21:35 eliotn hello
21:35 eliotn I AM A ROBOT
21:35 eliotn LOCALIZING IN 3... 2... 1...
21:36 Paradoxial *explosion*
22:08 thylon Lead acid battery only 6 inches tall
22:08 thylon hmm
22:24 thylon anyone have any good sites about interfacing arduino with a laptop for "additional processing"?
22:29 zhanx thylon ever hear of the program processing?
22:31 Tom_itx http://axis.unpy.net/01198594294
22:31 Tom_itx http://emergent.unpythonic.net/01198594294
22:31 Tom_itx http://media.unpythonic.net/axis-files/01198594294/halintf.pde
22:32 thylon http://www.acraigie.com/programming/firmatavb/default.html
22:37 thylon Tom_itx what language is that?
22:38 Tom_itx that's to use an arduino with emc
22:40 thylon halfway through this video, this guy has interfaced his laptop with the servos on the wall-e
22:40 thylon http://www.youtube.com/watch?v=OJiMUzJHYFk
22:40 thylon to the point where the arrow keys directly control it
23:30 rue_house boiler is pushing a 24.5c rise
23:30 rue_house storage tank cant keep up
23:30 rue_house rising at 3c/min
23:30 rue_house on 40gal