#robotics Logs
Jul 18 2017
#robotics Calendar
12:23 AM rue_house: I have a video
12:26 AM rue_house: anniepoo_, of a screw sorter cart
02:01 AM rue_house: https://youtu.be/2UoOIluY6ck
04:37 AM Jak_o_Shadows: ohhhh
04:37 AM Jak_o_Shadows: neeeeat
04:41 AM Jak_o_Shadows: Also, veverak, I read about a bezier curve formulation that has implicit control points that the curve actually passes through
04:41 AM Jak_o_Shadows: (http://personal.mecheng.adelaide.edu.au/will.robertson/splines-matlab.html)
04:41 AM Jak_o_Shadows: So I was going to (eventually) swap to that formulation, and use IK to get a couple of good starting point
05:40 AM deshipu_ is now known as deshipu
06:36 AM veverak: :)
07:30 AM Jak_o_Shadows: What variety of IK do you use? From when I last looked, there was jacobian, cyclic coordinate descent, and maybe a couple of others
07:47 AM deshipu: I just calculate it in a closed-form formula
07:51 AM Jak_o_Shadows: ah, righto. Because your leg limits are such that there's only one solution?
07:56 AM deshipu: there are two, but I hardcoded to pick one of them
08:06 AM Jak_o_Shadows: Fair enough
08:06 AM Jak_o_Shadows: I suppose that my legs are more constrained than yours are even
08:06 AM Jak_o_Shadows: So I think there only is one solution.
08:24 AM deshipu: that should simplify things
08:29 AM veverak: yup
09:40 AM rue_house: the peak velocity occurs at the percentage of the target distance thats the ratio of the acceleration and decel rates
09:41 AM rue_house: from there, the velocity can be worked out as sqrt(a*x) where x is that position
09:46 AM rue_house: didn't calc that ratio right
09:47 AM rue_house: that should do it
09:48 AM rue_house: this looks good, cause its basically the old formula
09:48 AM rue_house: peakX = (this->end - this->start) * (this->accel / (this->accel + this->decel));
09:48 AM rue_house: this->vTop = sqrt( this->accel * peakX);
09:48 AM rue_house:
09:48 AM rue_house: / this->vTop = Min( sqrt(accel * ((end - start) / 2.0)), topSpeed);
09:49 AM rue_house: ... put the cap back in...
09:50 AM rue_house: .. that should actually do it
01:03 PM Snert_: http://www.cnn.com/2017/07/18/tech/cute-japanese-space-drone/index.html
01:19 PM deshipu: cute
02:23 PM Snert_: I want detail! How does the spaceball manuever around?
02:23 PM Snert_: whirling gyroscopes I guess?
02:49 PM peepsalot: it says it has 12 propellers
02:49 PM peepsalot: which I'm guessing are inside those little nozzles that look like passenger airplane A/C vents
03:03 PM Snert_: oh yea...makes sense
03:33 PM deshipu: veverak: https://hackaday.io/project/6303-ros-hexapod-robot-called-golem-running-ros
07:22 PM veverak: interesting
07:22 PM veverak: like hte CPU unit
07:26 PM anniepoo_: I have 4 servos to be connected to an arduino.
07:26 PM anniepoo_: I was going to make a veloboard just for neatness.
07:27 PM anniepoo_: the arduino has female dupont connectors, so do the servos
07:28 PM anniepoo_: But the veloboard has copper pads on only one side
07:29 PM anniepoo_: I plugged male headers into the arduino, put a board on them, soldered in place, removed board and sawed away excess
07:29 PM anniepoo_: but this makes the servos need male headers inserted 'backwards' , sticking up from the copper side
07:29 PM anniepoo_: how do I deal with these?
07:35 PM rue_house: anniepoo_, did you see the video?
07:35 PM anniepoo_: no, hang on
07:36 PM rue_house: anniepoo_, plug a male-male header into the arduino to make the male headers you might want without having to modify them
07:37 PM anniepoo_: Hmm... ok, maybe that's something I don't have
07:38 PM anniepoo_: I have jumpers -
07:38 PM anniepoo_: that'd work, of course, but wouldn't be 'neat'
07:38 PM rue_house: long pins on both sides of the tie-bar
07:38 PM veverak: hmm
07:38 PM veverak: intel nuc looks like interestin choice for robot
07:39 PM anniepoo_: yes, that's hwat I need
07:39 PM rue_house: https://youtu.be/2UoOIluY6ck
07:40 PM anniepoo_: omg - it's working!
07:40 PM rue_house: I use them in breadboards too, for plugging in servos
07:40 PM rue_house: well, it goes to a position its told to, goes home, and can tip back forth and the like
07:40 PM anniepoo_: nice!
07:40 PM rue_house: I left it running a cycle last night, it should still be going
07:41 PM rue_house: I'll check later
07:41 PM Tom_L: what more could you ask for in a pet
07:41 PM rue_house: I think I need 2 hours sleep
07:55 PM rue_bed: I need to design a 'dove tail ' for the pipes to 'hook' them onto the 2x4
07:55 PM rue_bed: ^^^ RUE_MOHR, THATS A HINT ^^^^
08:09 PM robopal: anniepoo_, where should I follow you? instagram?
08:10 PM robopal: do you have a youtube channel?
08:13 PM robopal: need to see that snowman moving at some point :P
08:16 PM anniepoo_: yes, hang on
08:16 PM anniepoo_: the snowman's not finished, the above discussion aobut headers was for snowman
08:17 PM anniepoo_: https://www.youtube.com/channel/UCfWpIHmy5MEx2p9c_GJrE_g
08:17 PM anniepoo_: but that's playing with prolog, the Prolog language youtube channel we're making the snowman for
08:20 PM anniepoo_: I just got an Echo. Going to wire up echo to take NLP commands, following sam's setup, then we'll feed it a song and it'll use the SIATEC algorithm to find the beats, then use dcg's to construct a dance that 'makes sense' from them
08:20 PM anniepoo_: and feed that to the snowman robot using the arduino/prolog stuff we did a few weeks ago
08:20 PM anniepoo_: 8cD might be some constraint programming in there as well
08:22 PM anniepoo_: and fwiw the 'linking open data with wouter beek' video has an announcement of a new cool thing - they've managed to compress the entire semantic web into 304 GB
08:40 PM anniepoo_: .
08:41 PM Tom_L: o
08:42 PM anniepoo_: O
08:42 PM Tom_L: ¿
08:42 PM anniepoo_: . o O ( wonders about the sanity of people hanging out on #robotics )
09:17 PM rue_bed: zhanx, Tom_L tell me its impossable for some reason, to turn a 4 stroke engine into a 2 stroke
09:18 PM rue_bed: I need to design those hangers for the screw sorter
09:18 PM rue_bed: and print 20 or so
09:18 PM rue_bed: then I know the spacing and can start coding the put-away code
09:18 PM rue_bed: zhanx, .....
09:19 PM rue_bed: Tom_L, planes, are planes 2 stroke?
09:19 PM rue_bed: radial engines
09:19 PM anniepoo_: robopal - I also have an instagram
09:19 PM anniepoo_: http://instagram.com/anneogborn/
09:20 PM zhanx: rue it is
09:20 PM rue_bed: good why
09:20 PM rue_bed: will I blow the crank case?
09:20 PM zhanx: your crank, stroke, timing
09:20 PM rue_bed: you double the lobes on the cam
09:20 PM rue_bed: use the valves
09:21 PM rue_bed: plumb the intake to the crank case
09:21 PM rue_bed: move the carb to it, add a reed valve
09:21 PM zhanx: and time it how
09:21 PM rue_bed: mix the fuel
09:21 PM * zhanx waits
09:21 PM rue_bed: there are 2 lobes on the cam
09:22 PM rue_bed: their both 1 sided
09:22 PM rue_bed: you take a welder,grinder, make them 2 sided
09:22 PM zhanx: and waiting still
09:22 PM rue_bed: drill a small hole in the back of the crank connector for oil?
09:23 PM zhanx: rue, how is this, flat out not worth the effort
09:23 PM rue_bed: I dont know the displacement of the compression stroke on a 2 stroke
09:23 PM rue_bed: where the hell do I find a 2 stroke 2 HP!?
09:24 PM zhanx: you make a cast one.
09:24 PM zhanx: that is a hot or miss engine
09:24 PM rue_bed: cant recall the last time I saw a lawn-boy mower
09:24 PM rue_bed: hit or miss!?
09:24 PM zhanx: google it
09:24 PM rue_bed: their are diesel aren't they?
09:24 PM zhanx: well gas too
09:25 PM rue_bed: where they 2 stoke ?
09:25 PM rue_bed: somehow I thought they were 4
09:25 PM zhanx: yes not everyone had 4's etc
09:25 PM rue_bed: oh god, oh god, oh god, I'm gonna end up trying this, I feel it in my boners
09:25 PM rue_bed: er,. bones
09:26 PM rue_bed: oooooooooh
09:29 PM zhanx: bad rue
09:29 PM rue_bed: I wonder, the horiz shaft or a vert shaft
09:29 PM zhanx: horiz is normal
09:29 PM rue_bed: horiz shaft is harder to find, but I have one
09:29 PM rue_bed: lots of vert mower engines
09:29 PM rue_bed: its for the mecha
09:29 PM rue_bed: run those two compressors
09:29 PM rue_bed: I know, I'll JUST start with modifying the cam
09:29 PM rue_bed: .... just for kicks
09:29 PM rue_bed: right!?
09:29 PM zhanx: go slow on the cam
09:29 PM zhanx: super slow
09:29 PM rue_bed: I'm glad I dont have a 2 cyl to make into a 1 cyl 2 stroke
09:29 PM zhanx: lots of testing
09:29 PM rue_bed: weld weld weld grind grind ~~~~ding~~~~~
09:29 PM rue_bed: assuming its not PLASTIC
09:29 PM rue_bed: }:|
09:30 PM rue_bed: I think its old tho, should be metal
09:30 PM rue_bed: ooooooh
09:30 PM rue_bed: k
09:30 PM rue_bed: zhanx, WHY ME
09:30 PM zhanx: you do it not me
09:31 PM zhanx: heck i got 5 transmission's and 8 clutch breaks to do by friday
09:31 PM zhanx: that will not happen
09:31 PM rue_house: instead of just building a printer
09:32 PM zhanx: i worked 14 hours everyday for a while, i want to just build a printer
09:34 PM rue_house: .... I thougth you said you were gonna use the money from all the working to just buy one?
09:34 PM rue_house: could you make up your mind?
09:34 PM rue_house: want me to give you the shape to make for the first peice?
09:34 PM zhanx: rue can i have time to buy one?
09:35 PM * rue_house segfaults and hides in a corner
09:35 PM zhanx: if i can research fully the one i want i will buy it
09:36 PM rue_shop3: you could have everything by now
09:36 PM rue_shop3: just be waiting on the nozzel
09:36 PM zhanx: true very true
09:36 PM rue_shop3: who was in my shop!?
09:36 PM zhanx: but i did buy parts for my toy also
09:36 PM * rue_shop3 sniffs the air
09:37 PM anniepoo_: 8cD <-- currently writing announcement of security vulnerability
09:37 PM rue_shop3: good news anniepoo_ the sorter has been doing that move for 24 hours now, and its still doing it
09:37 PM anniepoo_: nice!
09:37 PM rue_shop3: :)
09:38 PM anniepoo_: so how's it going to work?
09:38 PM rue_shop3: AND better yet, the nut I put in the tray, IS STILL THERE!
09:39 PM rue_shop3: screw is put on try by system, robot puts tray on scale, program generates bin number, robot pours screw on that, screw gets dropped in bin
09:39 PM rue_shop3: (tray tips left and right)
09:40 PM rue_shop3: bad news, I'm going to pull an old engine out of storage, and take the cam shaft out of it
09:40 PM SpeedEvil: At least you can sort the screws easily
09:41 PM zhanx: if i could spend a week at rue's
09:41 PM rue_shop3: damn, carb is quite shot, I'll have to fuel inject it too
09:41 PM anniepoo_: once you sort your own, you might find you've got lots of screws of one kind. You can put them on ebay.
09:45 PM zhanx: rue soak the carb in vinegar
09:46 PM SpeedEvil: Balsamic?
09:46 PM zhanx: nope white plain vinegar
09:47 PM rue_shop3: ok I emptied the tar out of the crank case
09:47 PM rue_shop3: zhanx, its aluminum, and peices are missing
09:47 PM zhanx: pieces as in?
09:59 PM anniepoo_: ok, I'm off to go make some more progress on dancing robot.
10:11 PM rue_shop3: CANT GET TEH OLD PULLEY OFF
10:25 PM Luminax-Work is now known as LuminaxWk
10:31 PM anniepoo_: 8cD hardware is as done as it's going to get until software proceeds
10:46 PM rue_shop3: had to destroy the pulley
10:47 PM rue_shop3: few cuts in the output shaft, it'll libve
10:47 PM rue_shop3: got the cam out
10:47 PM rue_shop3: its all metal
11:00 PM rue_shop3: ok, that wasted 1.5 hrs
11:00 PM rue_shop3: ok, uh
11:00 PM rue_shop3: holder
11:00 PM rue_shop3: fore tubes
11:01 PM rue_shop3: at some points its going to get so bad I'll be the same off just mashing the keybaord
11:01 PM Tom_itx: rue_shop3, you live in a forest. you tell me where you find a 2hp 2stroke chainsaw engine.
11:02 PM rue_shop3: chainsaw couldn't be 2hp could it?
11:02 PM Tom_itx: big ones are i bet
11:02 PM Tom_itx: and if you pipe them right you could get more
11:03 PM Tom_itx: https://www.amazon.com/Husqvarna-240-Chainsaw-952802154-16-Inch/dp/B0055RSKFU
11:03 PM Tom_itx: bingo
11:04 PM rue_shop3: 38cc
11:04 PM rue_shop3: I wonder what this thing is
11:04 PM Tom_itx: https://www.amazon.com/dp/B008KSZ3QA/?shop28-20
11:04 PM Tom_itx: 42cc
11:06 PM anniepoo_: it's a small chain saw
11:06 PM Tom_itx: http://www.ebay.com/itm/Outboard-Engine-Motor-2HP-53cc-4-Stroke-Engine-Fishing-Small-Boat-Dinghy-kayak-/192243661936?hash=item2cc29d7c70:g:9iwAAOSw2gxYxV5s
11:06 PM Tom_itx: 53cc
11:06 PM Tom_itx: err that's 4 stroke
11:07 PM Tom_itx: http://www.ebay.com/itm/New-Portable-Outboard-Motor-Boat-Engine-3-5HP-2-Stroke-With-Water-Cooling-System-/272529549262?hash=item3f7406e7ce:g:ZdQAAOSw~rpZTJXs&vxp=mtr
11:07 PM Tom_itx: 3.5hp 2 stroke
11:07 PM Tom_itx: water cooled
11:07 PM rue_shop3: 2 should do it
11:07 PM rue_shop3: but I dont have funds
11:07 PM Tom_itx: also
11:07 PM rue_shop3: the whole project is $240
11:07 PM Tom_itx: what about snowmobiles?
11:08 PM Tom_itx: are they 2stroke?
11:08 PM Tom_itx: the list just keeps going
11:09 PM Tom_itx: 5hp lawnboy 2stroke mower
11:09 PM rue_shop3: yea
11:10 PM rue_shop3: havn't seeen a lawnboy in a LONG time
11:10 PM Tom_itx: http://www.diygokarts.com/vb/archive/index.php/t-785.html
11:10 PM Tom_itx: gokarts
11:10 PM Tom_itx: are mostly 2 stroke
11:10 PM Tom_itx: i had one
11:10 PM Tom_itx: definitely more than 2hp
11:11 PM Tom_itx: rotax from a ski do
11:12 PM Tom_itx: those may be 4 stroke
11:12 PM rue_shop3: it gives me things to put a search out on
11:12 PM Tom_itx: i bet i could come up with more
11:12 PM rue_shop3: this engine I tore apart was prettymuch scrap anyhow
11:13 PM rue_shop3: there is a possability of finding a scrapped snowmobile, but I think it would be larger than 2hp
11:13 PM Tom_itx: https://www.rbmods.net/ops_marine_45_engine_-winner_of_20_world_championship.html
11:14 PM Tom_itx: i had several of those
11:14 PM Tom_itx: 2.6 hp
11:14 PM Tom_itx: tiny
11:14 PM Tom_itx: expensive too
11:14 PM Tom_itx: model boat racing
11:14 PM rue_shop3: yea, I been really surprised that a boat engine hasn't come up yet
11:15 PM Tom_itx: there was also an OPS 90
11:15 PM anniepoo_: https://www.youtube.com/watch?v=ygl2ZOQFH_4
11:15 PM Tom_itx: i had a custom expansion pipe for mine
11:16 PM Tom_itx: boat engine was mentioned above
11:17 PM Tom_itx: https://www.youtube.com/watch?v=KsjRFE04ryU
11:17 PM Tom_itx: mine looked exactly like that but with a bigger expansion pipe
11:17 PM Tom_itx: that's the stock pipe
11:18 PM Tom_itx: and i ran 40% nitro and sometimes 60
11:18 PM Tom_itx: didn't use the stock carb either
11:18 PM rue_shop3: hmm
11:28 PM rue_shop3: hmm
11:28 PM rue_shop3: the dovetail holder for the pipe will hold it out about 8mm
11:28 PM rue_shop3: dont know if that throws things out too much
11:44 PM rue_shop3: today I taught myself more about state machines
11:45 PM rue_shop3: started to make progress on understanding how to use multiple state machines togethor
11:47 PM * SpeedEvil puts on some 808 state.