#robotics Logs

Feb 27 2015

04:46 RustyShackleford is it feasible?
04:46 RustyShackleford the safe I have has 50^3 combinations
04:47 deshipu I'm picturing http://www.bakeryandsnacks.com/var/plain_site/storage/images/publications/food-beverage-nutrition/bakeryandsnacks.com/r-d/hydrocolloids-improve-seasoning-adhesion-on-crackers-study/8484065-1-eng-GB/Hydrocolloids-improve-seasoning-adhesion-on-crackers-Study.jpg
04:47 RustyShackleford saltines are always a safe cracker choice
04:48 orlock but how do you handle the feedback?
04:48 deshipu some kind of vibration sensor? microphone?
04:48 RustyShackleford the idea would be to brute force it
04:48 RustyShackleford what sort of feedback do you mean?
04:49 orlock oh, never mine then
04:49 RustyShackleford cracking a safe by sound would be pretty darn cool
04:50 RustyShackleford anyway, one combination could take lets say 10 turns
04:50 RustyShackleford i have no idea how fast a stepper motor could do that
04:52 Stellar_Mind I think brute force shouldn't be the first choice, there should be some feedback. Don't you think?
04:53 RustyShackleford cracking a safe isn't that easy unfortunately
04:53 RustyShackleford i found this safe inside a wall, we moved here in august
04:54 RustyShackleford there are shortcuts if you know about the lock/safe
04:55 RustyShackleford so a standard gym lock, for example, has 40 numbers printed on it, but only 17 or so positions
04:55 RustyShackleford so if the combo is 10 20 30, then 10 21 30 and 10 19 30 would open it too
04:55 Stellar_Mind Do similar safes give a smilar click on opening? (I am guessing based on completely scientific resources like bollywood movies, just throwing around ideas :P)
04:55 Stellar_Mind oh
04:55 Stellar_Mind didn't know that
04:56 RustyShackleford i couldn't find anything about doing it by sound
04:56 RustyShackleford anyway if I can't build a robot to do this, i'm gonna pry the damn thing apart
04:56 Stellar_Mind Either way it's gonna be brute force
04:56 Stellar_Mind :D
04:56 RustyShackleford haha nice. i literally loled
04:56 RustyShackleford brute force
04:57 RustyShackleford anyway, if it takes 1 minutes per combination we try, that's 86 days worst case
04:57 orlock hard part will be the pull
04:57 orlock leftright, leftright, leftright, pull
04:58 Stellar_Mind Without any down time.
04:58 Stellar_Mind yeah that's what i thought
04:58 Stellar_Mind how would the microcontroller know
04:58 orlock as long as the stepper can turn it without any extra gearing needed
04:58 Stellar_Mind if the safe is open or not?
04:58 RustyShackleford orlock: on this safe, you rotate counterclockwise until it unlatches
04:58 RustyShackleford but yeah, figuring out the extra torque there is a problem
04:59 lock has a pile of steppers hammering away in the
04:59 orlock ones getting hot to touch
04:59 orlock i think i'm mmssing steps and under extruding due to it
05:00 RustyShackleford so i should probably just smash it open
05:00 RustyShackleford i'll bet it's empty anyway
05:00 orlock take a pic
05:00 orlock put it on reddit
05:00 orlock ask for funds to hire locksmith
05:00 RustyShackleford i'd get more karma if i cracked it
05:00 RustyShackleford and showed them how I designed a robot to do it
09:27 rue_more wow, thingverse has hinges nailed
09:27 deshipu also, frogs
09:27 rue_more hah
09:27 deshipu and teapots
09:28 rue_more atleast hinges register on a usefullness scale
09:29 deshipu unlike teappots
09:31 rue_more hmm I havn't looked up quadcopter yet...
09:36 deshipu quadcopters register negative on the usefullness scale
09:36 rue_more ?
09:36 deshipu they suck out your time and money :)
09:36 rue_more I should think there would be lots of good parts kits
09:37 deshipu well, 3d printers too, actually
09:37 deshipu you think they would be useful
09:37 deshipu until you try one
09:37 rue_more I'v made some great stuff so far
09:37 rue_more and I'm not including the owl when I say that
09:37 deshipu rue_more: is the owl artificial?
09:38 veverak deshipu: 3D printers are awesome
09:38 veverak when you got working 3d printer
09:38 veverak :)
09:38 rue_more http://www.thingiverse.com/rue_mohr/designs
09:38 deshipu veverak: that seems to be rarer than a unicorn though
09:38 rue_more why are hosecaps $2ea?
09:39 veverak deshipu: my experience tells me that Stratasys 3d printer is reliable
09:39 rue_more hopefully the world will print them and the price will drop
09:39 deshipu rue_more: demand
09:39 veverak or at least the one on local university, either it prints
09:39 veverak or you call support and guy comes to repair something
09:39 veverak :D
09:39 rue_more I suppose its like a car, if you know what your doing and how it works, your ok
09:40 veverak yeah
09:40 rue_more tho my mendel is pretty plug and play right now
09:40 rue_more I'v not had to modify anything on it in well over 20 prints
09:40 rue_more and its still a mess
09:40 deshipu 20 prints, wow
09:40 veverak nah
09:41 rue_more I'm not going crazy on printing everything
09:41 veverak I really need some cable managment
09:41 deshipu I didn't know it can stay that long in one piece ;)
09:41 veverak sill sucks on my machine
09:41 deshipu veverak: go wireless ;)
09:41 deshipu veverak: this way it can keep printing while exploding ;)
09:41 rue_more the first 1kg of plastic was a bit of a fiasco
09:42 deshipu veverak: by the way, about your rover
09:42 deshipu veverak: I was wondering, do you have any solution for the threads tension?
09:42 deshipu veverak: because you know, they get loose over time
09:42 rue_more tracks?
09:43 veverak deshipu: I can add tension wheel
09:43 rue_more I came up with some great printed tracks
09:43 deshipu veverak: you need to pick up slack somehow
09:43 rue_more no wheels so I havn't posted
09:43 deshipu veverak: I've seen those tracks with the wheels on a small lever
09:43 deshipu veverak: so that the weight of the robot works for tensing them
09:44 veverak deshipu: I was thinking that moving the front wheel would be best
09:44 veverak rue_more: https://cloud.veverak.org/public.php?service=files&t=3e47d1f2eec7d491c4b9533283ae77f8 I've got wheels!
09:44 veverak :D
09:46 rue_more :)
09:46 deshipu veverak: what are you using for the binding pins?
09:47 veverak deshipu: nothing yet
09:47 veverak there is only 1mm thick hole
09:47 veverak or 2mm?
09:47 rue_more I used 3" nails, cut to length
09:47 veverak propably steel wire with bended ends ?
10:51 veverak FUUUU
10:51 veverak one of my z-motors on i3 is broken
10:51 veverak dunno why :/
10:54 veverak it's like, it tries to move
10:54 veverak but skips it
10:54 veverak or is not strong enough
10:54 veverak than it tries to move again...
11:03 rue_shop3 you should be able to easily turn the screw by hand when the motor is disconnected
11:04 rue_shop3 if the Y carrige is not level, its probably jammed the motors screw
11:04 rue_shop3 RUN THE PRINTER SLOWER
11:04 rue_shop3 dial it down to about 25% or 30%
11:04 veverak nah
11:04 veverak bad nuts
11:04 veverak :/
11:05 veverak rue_shop3: wasn't able to turn by hand
11:05 veverak really considering buying that cheap ball screws from china
11:05 veverak horrible ball screws, but sitll better than threaded screw
11:05 rue_shop3 threaded rod works fine
11:06 rue_shop3 if you take the rod and nut off, can you run the nut by hand across the rod?
11:06 rue_shop3 its verry unusual for a rod or nut to be readed wrong,
11:06 rue_shop3 not to say it might have a damaged thread
11:07 veverak rue_shop3: used different not, works just fine :)
11:07 rue_shop3 if its been hit with somwthing hard
11:07 rue_shop3 are you in the states?
11:07 veverak nope
11:07 rue_shop3 ah
11:07 veverak rue_shop3: it is all metric!
11:07 veverak ;D
11:07 rue_shop3 fair enough
11:08 rue_shop3 lots of people in the US go to a lot of trouble to use metric on everything, which is stupid, for the resolution of it, imperial is even fine on the Z axis
11:11 veverak rue_shop3: I just suppose that
11:11 veverak 'I need nut now... wow there is one laying on the table randomly with dia I need'
11:11 veverak I suppose that nut was there for some time
11:41 rue_shop3 upc bar codes use 4 bit pdm
12:14 veverak well
12:14 veverak it's hard to print properly
12:14 veverak if you use 0.5 width for line
12:14 veverak and you got 0.8 nozzle...
13:51 veverak RifRaf: ping
13:59 veverak deshipu: hmm, I thought about it
13:59 veverak deshipu: and I will postpone this first version, and implement tensioning into it
13:59 veverak practically, I will add screw so I can move fron wheel :)
14:00 veverak *front
14:03 veverak not to mention that I should do the weight calculation
14:05 deshipu veverak: better safe than sorry
14:05 veverak 5yeah
14:05 deshipu veverak: then again, making a lot of prototypes works too
14:05 verak started to print beta-wh
14:05 veverak they are bigger tahn I supposed they will be
14:05 veverak deshipu: yeah, slowly starting with that
14:06 veverak but it looks like I should be able to finish tracks/wheels really soon
15:38 RifRaf https://www.youtube.com/watch?v=M8YjvHYbZ9w
15:38 RifRaf veverak, hello
15:40 veverak RifRaf: hi, I've got your frame O:) (If you remember)
15:40 veverak i3, metal, 4mm thick
15:40 veverak it's awesome! but have you ever thought about using ball screws for z axis?
15:40 RifRaf squirrelczech?
15:40 veverak exactly
15:40 RifRaf ok cool, i remember
15:40 veverak yeah
15:40 RifRaf i have used threadless ballscrews
15:40 veverak well, I wanted to use ball screws
15:41 veverak but I need few more mm's between the smooth rod and ball screw
15:41 veverak so I have to modify the frame
15:41 RifRaf https://www.youtube.com/watch?v=hN1LMJ9FPqY
15:41 RifRaf can't you just modify the z parts? thats wat i did for the threadless ones
15:42 veverak I suppose?
15:42 veverak just thinking what is the 'lesser evil'
15:42 veverak I think I can just modify the top part of te frame
15:42 RifRaf yu can see the modifired parts in that clip
15:42 RifRaf yes the top and the Z motors holders
15:42 veverak just part of the mottors
15:43 veverak the 'U' shape that holds the motor can remain on the place
15:43 veverak I will just move the holder of the smooth rod
15:44 veverak nah
15:44 veverak I see that threadless ballscrew is good idea... still can't get to want it :/
15:45 veverak while this seems http://www.ebay.com/itm/CNC-SFU1204-Ball-Screw-L200mm-Ballscrew-With-SFU1204-Single-BallNut-/140982945410?pt=LH_DefaultDomain_0&hash=item20d33d0682 as do it once and don't care about it
15:45 veverak afaik I can't get solution that would be 'better' (if we don't count money effeciency)
15:46 RifRaf yep would definatatly be an improvement
15:46 veverak and the money part...
15:46 RifRaf not one i have had the need for yet though
15:46 veverak it's not so big ammount of money for these 'chinese quality' and I suppose I would get rid off buchload of problems
15:46 veverak only problem is that the 'nut' is too big :/
15:47 RifRaf i sent you the cad files didn't i? so change it :)
15:47 veverak yeah
15:48 veverak just wanted to ask if you have some exp. with modification such as this :P :D
15:48 veverak seems like I was right with the idea to just modify top
15:48 veverak anyway
15:48 veverak maybe
15:48 RifRaf yes i have done it, just showed you
15:48 veverak I can modify the nut O:)
15:48 RifRaf does not mater threadless or not, still same changes
15:48 veverak exactly
15:50 veverak hmm
15:50 veverak I will consider the nut modification too
15:50 veverak by my calculations
15:50 veverak I need 1.5mm of space
15:51 RifRaf have you got the ballscrews already?
15:51 veverak nope
15:51 veverak RifRaf: 1. plan the thing
15:51 veverak 2. buy things
15:51 veverak 3. replan agian
15:51 veverak :D
15:51 veverak *again
15:51 RifRaf ok, sounds like a plan
15:58 RifRaf veverak, did you get any of your tank printed yet?
16:00 veverak slowly
16:00 veverak printer is like 'no printing today'
16:03 veverak RifRaf: printed chains
16:03 veverak looks awesome so far
16:06 RifRaf cool, any pictures?
16:06 veverak nope :/
16:06 veverak cam is in different town now
16:07 veverak nah
16:07 RifRaf k
16:07 veverak small bug on the tracks, but nothing big
16:08 veverak one wall too thin :)
16:31 veverak nah
16:31 verak is looking at his
16:31 veverak i've got that feeeling
16:31 veverak that it's wrong
16:31 veverak but I don't have 'specific point' that says it's wrong
18:09 veverak https://github.com/SquirrelCZE/Rover/
18:09 veverak if somebody is interested in the source of the tank-robot
19:13 rue_more so when are you going to start assembly?
21:34 rue_bed hmm
21:35 rue_bed 2 bit pwm modulated, 7 slot
21:35 rue_bed 4 charters/word
21:36 rue_bed 4111
21:36 rue_bed 3211
21:36 Tom_itx bed already?
21:36 rue_bed had a nap
21:37 rue_bed 2221
21:37 rue_bed 2212
21:37 rue_bed 2122
21:37 rue_bed 1222
21:38 rue_bed 1123
21:38 rue_bed 1114
21:38 rue_bed hmm, I think I screwed up
21:39 rue_bed and I think I'm comming down with something
21:41 rue_bed 4111 3211 2311 1321 2221 2212
21:41 rue_bed whats all I get get that add up to 7, and aren't reversable
21:42 rue_bed 4 digits, add to 7, each digit is 1-4
21:42 rue_bed I fail
21:51 rue_shop3 oh I forgot to move 4 around
21:51 rue_shop3 http://blog.dukten.com/wp-content/uploads/2010/09/code-table.jpg
21:51 rue_shop3 this is the answer