#robotics Logs

Nov 12 2013

01:59 GargantuaSauce ~15W to hold that at widest stance
02:01 MrCurious1 wont it self hold at wide stance without any power?
02:02 GargantuaSauce uh no
02:02 GargantuaSauce the servos go all floppy!
02:02 GargantuaSauce it is holding the body ~4cm above the ground
02:02 MrCurious1 ok
02:03 GargantuaSauce and i lied, it isnt the WIDEST stance just the default / widest i'll let it get
02:03 GargantuaSauce last two joints bent 45 degrees
02:03 Curious1 yawns too hard and accidentally turns himself inside
02:03 GargantuaSauce gotta adjust one hip joint which it would appear I accidentally offset
02:03 GargantuaSauce and clean up the wiring, then pics
02:03 GargantuaSauce then walking!
02:04 MrCurious1 regret spending on those ervos yet
02:04 MrCurious1 servos
02:04 GargantuaSauce 300 bucks well spent i think
02:04 GargantuaSauce well we'll see how they perform actually moving
02:04 MrCurious1 true
02:04 Curious1 tips had and folds himself into
02:05 GargantuaSauce i noticed some jitter when i was testing with one leg but i think i can chalk that up to the bolts being loose as hell and thus the structure flopping around and that's hard to stabilize
02:05 GargantuaSauce i just picked it up and shook it by the body and nothing moved
03:10 theBear don't shake the baby !
06:07 GargantuaSauce http://workman-industries.net/images/hexapod/4dof-2.jpg OBEY
06:08 GargantuaSauce still need to make feets
07:34 GuShH GargantuaSauce: what are you going to use for the feet? looking great
07:34 GargantuaSauce i am going to print hollow cylinders with bolt holes at one end to match the brackets, and gluegun halves of rubber bouncy balls on the other end
07:35 GuShH hrmm
07:35 GargantuaSauce hopefully that will minimize the amount that i piss off the downstairs neighbours, and maximize grip on hardwood floor
07:36 GuShH speaking of neighbours here goes again the neighbour's gardner fucking things up
07:36 GuShH brb
08:30 GuShH look it's KongfuPanda
08:31 KongfuPanda omg
08:31 KongfuPanda it's not me
08:32 GuShH no?
08:41 Tom_itx KongfuPanda, make touch sensitive sensors for the feet
08:44 Tom_itx http://www.huv.com/blog/
08:44 Tom_itx somewhere in there he's got some feet sensors for the MicroRaptor
09:30 KongfuPanda GuShH, what were we talking about?
09:30 GuShH nothing
09:31 KongfuPanda GuShH, about a hexapod?
09:31 GuShH not me
09:31 GuShH that was GargantuaSauce
09:32 GuShH well I asked one question about it that's all
09:34 GuShH KongfuPanda: http://jor1k.widgetry.org/
09:59 GargantuaSauce one bad servo
09:59 GargantuaSauce middle gearshaft is bent, quite considerably
10:00 GargantuaSauce damaged during assembly i guess
10:00 GargantuaSauce glad i have one spare
10:00 GuShH Now you have no spares.
10:00 GargantuaSauce yeah
10:00 GargantuaSauce should have got 2-3
10:00 GargantuaSauce because i'll probably destroy a couple more
10:00 GuShH SHOULDA COULDA WOULDA your best friends
10:01 GargantuaSauce this thing is a fucking beast though
10:01 GargantuaSauce i picked up one leg
10:01 GuShH can it carry me?
10:01 GargantuaSauce or rather
10:01 GargantuaSauce i picked IT up by one leg
10:01 GuShH isn't that how one gets a shaft bent? heh
10:01 GargantuaSauce not that shaft
10:01 GuShH it's a beast that bends when you pick it up!
10:02 GuShH I like it, but I don't see a use for it
10:02 GuShH Similar situation with flyback and his man parts
10:02 GargantuaSauce it makes wonderful stompy noises and scratches up my floor
10:02 GuShH You can get a woman to do that for you just by walking on heels
10:03 GuShH And, she could find a use for that bent shaft.
10:05 GargantuaSauce i dropped one of the gears and the grease on it found all the dust and hair my broom did not
10:06 GuShH Another reason to get a woman!
10:08 GargantuaSauce nah i definitely didnt bend the shaft with external abuse
10:08 GuShH Maybe you bent it with your MIND
10:08 GargantuaSauce the spline is supported by a pair of bearings
10:08 GuShH Speaking of bending, I gotta cut and bend some tubing
10:08 GuShH real ball bearings?
10:08 GuShH or just bushings
10:10 GargantuaSauce radial ball bearings
10:10 GargantuaSauce open and greased
10:10 GuShH no need for shielding there
10:10 GuShH less cost
10:10 GargantuaSauce yeah
10:10 GuShH less weight
10:10 GuShH MORE CHINA
10:10 GargantuaSauce these are pretty sweet servos for 10 bucks
10:11 GuShH haven't seen them but they look nice
10:11 GuShH as long as the gears are metal and they have proper bearings...
10:11 GargantuaSauce yup
10:11 GuShH and they aren't a stutter fest like the cheaper ones
10:11 GargantuaSauce the drive gear is fucking beefy
10:23 GargantuaSauce looks like the angle bias on the fourth joint was a mistake, can't do very narrow stances
10:24 GargantuaSauce i'll just ignore it for now though, no frickin way i'm going to redo another 60 screws
10:27 GuShH does this work for you? www.aluar.com.ar ... doesn't ping back, tried from another ip same deal
10:27 GargantuaSauce times out
10:27 GuShH bastards
10:27 GuShH that's our only aluminum smelter in the entire country and they can't keep their site up
10:27 GuShH you gotta be shitting me
10:27 ShH feels like shooting something to get the frustration
10:28 GargantuaSauce yes, photography is an excellent stress reliever
10:32 GuShH no, guns are.
10:32 GuShH destruction = instant gratification
10:33 GuShH plus they're forever if you take good care of them... cameras tend to fall apart
13:44 flatr0ze hello
13:45 SquirrelCZECH hmm
13:45 SquirrelCZECH my gyroscope detects the rotation itself, and calcualtes angle from that
13:45 flatr0ze I'm trying to drive a big stepper (6-wire, using 4 wires with easydriver 4.1). It seems to be too weak @ 12V. Could please someone suggest ways of improving the torque of my motor?
13:45 SquirrelCZECH now it sends only the "rotation aprt"
13:46 uirrelCZECH is thinking if he should calculate angle from that or no
14:12 flatr0ze what would be the most powerful stepper motor which could be driven by <=36V?
14:21 GuShH flatr0ze: you are doing it wrong
14:21 flatr0ze GuShH: why?
14:21 GuShH because you are!
14:21 flatr0ze :(
14:21 flatr0ze I'm tryig to use Nema 17 right now, but it's not strong enough to rotate what I need
14:22 flatr0ze and the project I'm working on also requires speed... 3 turns per 1.5 sec.
14:22 ShH hands flatr0ze a V12 en
14:22 flatr0ze looking at Nema 34 right now, not sure if will be able to drive it with EasyDriver
14:22 flatr0ze GuShH: that helped, thanks
14:30 flatr0ze GuShH: seems like I may try to supply 36V to the motor I have via EasyDriver... got plenty of both, not really afraid to burn
14:30 flatr0ze GuShH: your idea with using v12 is very bad btw... my dad just kicked my ass for trying to disassemple his Mers
14:51 Tom_itx flatr0ze most any stepper can be driven like that
14:51 Tom_itx with a chopper drive
14:52 Tom_itx mine are running on 48v
14:52 Ubuntivity Hello
14:52 Tom_itx yeah yeah
14:52 Ubuntivity What is the drill bit used for cutting (rather than making holes) called?
14:52 Tom_itx flatr0ze, i'm getting 80ipm from mine
14:52 Tom_itx Ubuntivity an endmill
14:53 Ubuntivity thanks Tom_itx
14:53 Tom_itx ball nose, bull nose, roughing, flat etc
14:53 flatr0ze Tom_itx: I'm using http://www.originalmind.co.jp/useds/38176 this one, will try 30V today
14:53 Ubuntivity Tom_itx: can the regular drill bits be used for cutting as well?
14:53 flatr0ze can't find any good arduino-compatible driver for 50V
14:54 Tom_itx for cutting holes yes
14:54 Ubuntivity Tom_itx: I mean for cutting 'lines' rather than holes?
14:58 Tom_itx you want a single point cutter
14:59 Tom_itx not a drill
14:59 Ubuntivity Tom_itx: forgive my limited knowledge, but what is 'single point cutter'?
15:00 Ubuntivity I need to cut a material in a straigt line (like the CNC does) but manually, how can I use the drill for that?
15:00 Tom_itx http://www.google.com/imgres?imgurl=http://www.techno-isel.com/tooling/EngravingBits/Engraving-Bit.jpg&imgrefurl=http://www.techno-isel.com/tooling/EngravingBits/&h=200&w=69&sz=11&tbnid=0wQFVWyS48BYAM:&tbnh=90&tbnw=31&zoom=1&usg=__zxExvmmvkAzMxZmwZ6p1OjnATZc=&docid=Mxibt4YL9yrYjM&sa=X&ei=RZOCUtOKCKSY2AWf14GoBA&ved=0CFUQ9QEwAQ
15:01 Tom_itx cut or engrave?
15:01 Tom_itx cut you would use a slitting saw
15:01 Tom_itx or a regular saw
15:01 Tom_itx engrave you would use an engraving bit
15:01 Ubuntivity Sorry but I'm not native English
15:02 Tom_itx ^^ that is an engraving bit
15:02 Ubuntivity I think I need to use engraving technique to cut the material (for the sake of accuracy)
15:02 Tom_itx what are you cutting?
15:03 Ubuntivity Composite Aluminium Panel (Alcobond)
15:03 Tom_itx are you writing on it or wanting to cut it in half?
15:03 Ubuntivity I can't get it straight with my hand saw (and I can't get an electrical saw) but I have a drill
15:03 Tom_itx you won't do much better with a drill
15:04 Ubuntivity I'm thinking of 'motorizing' my workstation to make my part move in straight line (with the drill doing the cutting)
15:04 Tom_itx you _can_ get it straight with your hand saw if you work at it
15:05 Tom_itx if you cut across the piece instead of straight through it, it will come out alot straighter
15:05 Ubuntivity What do you mean by 'across'?
15:05 Tom_itx the width instead of the thickness
15:06 Ubuntivity Oh I see.. won't that make cutting more difficult?
15:06 Tom_itx it might seem that way but it isn't
15:06 Tom_itx start on a slight angle to get it started
15:06 Tom_itx then flatten it out until you have a 'line' cut across it
15:06 Tom_itx then cut thru it
15:07 Ubuntivity That will let me make use of the straigt-ness of the saw, right?
15:07 Tom_itx yup
15:07 Ubuntivity Thats really good idea, I've got to try that!
15:07 Ubuntivity Thanks a lot Tom_itx
15:07 Tom_itx just take your time getting the first marks thru it
15:08 Ubuntivity So you think this might be actually better than my drill idea?
15:08 Tom_itx quite sure of it
15:08 Tom_itx use lubricant on the blade too and it won't load up with material
15:09 Ubuntivity Honestly I've never used a lubricant nor did know I should!
15:09 Ubuntivity What are the types of lubricants?
15:09 Tom_itx aluminum will load up between the teeth
15:09 Tom_itx i use wd40 for that
15:09 Tom_itx or some kind of light oil
15:09 Ubuntivity Can I use any kind of oil or grease as a lubricant?
15:10 Tom_itx probably
15:10 Ubuntivity I know this might sound stupid, but can the cooking oil be used as well?
15:10 Tom_itx i dunno, you could try it
15:10 Tom_itx if it's all you have
15:10 untivity feels that he's gonna mess his workspace with
15:11 Tom_itx just a few drops at a time
15:11 Tom_itx not a swimming pool full
15:11 Ubuntivity :)
15:11 Ubuntivity Thanks
15:11 Ubuntivity You've helped me a lot today
15:12 Ubuntivity and -most importantly- helped me relax again
15:12 Ubuntivity Getting those straight lines wrong was driving me crazy!
15:13 Ubuntivity Tom_itx: can you please give me some comments on this: http://www.youtube.com/watch?v=e393Gh92htQ
15:14 Ubuntivity What can be done better, what was done wrong, etc...
15:15 untivity wonders if Tom_itx is still there
20:56 defaultro GargantuaSauce: Triffid_Hunter my DRV8825 Pololu arrived today. I hooked it up. Bipolar motor is working great. It is very strong. However, I would like to know how much the pot current limiting is set at
20:57 defaultro can I remove the stepper motor and put my multimeter instea in one of the coils?
21:05 robotustra no
21:06 robotustra you can to connect ampermeter sequentioally
21:07 robotustra cut 1 wire and put ampermeter between 2 contacts
21:09 defaultro ok
21:10 defaultro so remove 1 stepper wire from breadboard then connect it to either red or black probe, then the other probe, put it to the breadboard
21:12 Triffid_Hunter defaultro: no
21:13 Triffid_Hunter defaultro: measure the voltage on the face of the adjust pot. the datasheet has a mathematical algorithm that connects coil current to pot voltage
21:13 Triffid_Hunter defaultro: your multimeter is not capable of giving a useful reading due to the shape of the signals
21:13 defaultro on the face?
21:14 defaultro I didn't get it
21:14 defaultro maybe that's the VREF I read
21:16 Triffid_Hunter yeah vref, that's the one
21:17 defaultro ok, let me find the datasheet
21:19 defaultro lol, I couldn't understand a thing on the datasheet :)
21:21 Triffid_Hunter defaultro: http://www.pololu.com/product/2133 "Current limiting" section
21:21 defaultro ok
21:22 Triffid_Hunter "So, for example, if you have a stepper motor rated for 1 A, you can set the current limit to 1 A by setting the reference voltage to 0.5 V."
21:23 defaultro ok
21:23 defaultro mine is 0.4a
21:23 defaultro 12v
21:24 Triffid_Hunter defaultro: what's your supply voltage?
21:24 defaultro 12v
21:24 Triffid_Hunter yikes, driver isn't gonna like that much.. you'll have to set it below 0.4A
21:24 Triffid_Hunter or give it more volts
21:25 defaultro why won't it like it?
21:25 Triffid_Hunter no headroom. smart current-mode drivers need extra volts so they can keep the current smooth
21:25 defaultro right now it's working but i know what the current limiting is set at
21:25 defaultro oops
21:26 defaultro but I don't know what the current limiting value is
21:26 Triffid_Hunter that's what the vref test point is for...
21:26 defaultro I couldn't find the vref pin though
21:27 Triffid_Hunter then use the face of the pot
21:28 defaultro that's where I am confused. What is face of the pot mean? I know where the pot is
21:29 Triffid_Hunter defaultro: know what the face of a clock is? now take a look at the pot
21:30 defaultro ok. I see the pot, it's at the opposite end
21:30 defaultro but I don't see any pin labeled VREF
21:31 defaultro i'm uploading a pic
21:32 Triffid_Hunter that's why I keep saying measure the face of the pot
21:33 defaultro http://i.imgur.com/Dk9qKjt.jpg
21:33 rue_house usually pot faces are pretty relaxed
21:33 defaultro are you saying there is voltage on the pot knob?
21:34 rue_house knob is uyaually the wiper
21:34 Triffid_Hunter there's only so many times I can say it before I have to stop talking at all...
21:34 defaultro i'm really sorry but I don't get it
21:35 defaultro you said measure the face of the pot
21:35 defaultro I interpretted that as there is voltage on the screw
21:35 rue_house in grams, not oz
21:35 defaultro so am I right that there is voltage on it?
21:38 defaultro I just did. I set multimeter to 20 DCV. The value came out 0.5
21:38 defaultro i think it 0.05
21:39 defaultro i redid it. it is showing as 0.11 for a long time. What does it mean?
21:40 Triffid_Hunter defaultro: http://www.pololu.com/product/2133 "current limiting" section
22:01 defaultro I've read it 12 times now and I still don't get it :(
22:02 defaultro their terminologies are so confusing
22:03 defaultro "One way to set the current limit is to put the driver into full-step mode and to measure the current running through a single motor coil without clocking the STEP input."
22:03 defaultro That one is easy but you don't recommend it because you said earlier, multimeter reading the current will not be precise
22:04 defaultro Then this one "The ref pin voltage is accessible on a via that is circled on the bottom silkscreen of the circuit board." What the is silkscreen
22:05 defaultro The silkscreen i know is the one I used when painting over t-shirts
22:07 defaultro this is the silkscreen I know, http://www.printwand.com/blog/media/2012/01/silk-screen-printing.jpg but I don't see any silk material on the drv8825
22:10 robotustra http://www.lukhash.com/ music
23:41 MrCurious anyone used freemill?