#robotics Logs

Aug 06 2015

06:49 just_pink someone have an experience with the 80/20 products?
07:00 Jak_o_Shadows I've used maytec before
07:00 Jak_o_Shadows which I believe is similar
08:30 rue_school cans aren't worth it
08:30 Jak_o_Shadows heatsinks seem like they'd be good.
08:30 rue_school heatsinks did pretty good, funny metal
08:31 rue_school Id say heatsinks are "light" aluminum, must be an unusual alloy
08:31 rue_school old 5.25" floppy frames and hard drive frames are great
08:32 rue_school lawn mower engies
08:32 Jak_o_Shadows Yeah. They do seem different.
08:32 rue_school maybe heatsinks are just purer aluminum
08:33 rue_school its 'whiter' too
08:34 Jak_o_Shadows TBH, aluminium is an odd metal I think
08:34 Jak_o_Shadows and copper too
08:34 Jak_o_Shadows Ok, I only know squat about steel
08:35 Tom_itx rue_house, where are the pics of your foundry stuff?
08:38 rue_school hmm
08:38 rue_school http://ruemohr.org
08:38 rue_school lets hunt...
08:38 rue_school http://ruemohr.org/~ircjunk/projects/smelter/
08:38 rue_school I win
08:39 rue_school http://ruemohr.org/~ircjunk/projects/smelter/p1040233.jpg
08:39 rue_school I didn't take pics of the propane torch :/
08:39 Jak_o_Shadows Have you casted 3d printed stuffs?
08:39 rue_school yes
08:39 rue_school not with lots of success yet
08:41 Jak_o_Shadows That's something I am vaguely interested in doing in the (somewhat far) future
08:41 rue_school I have a split cope/drag, so I made a board with some flat sided prints, and all the channels on it
08:42 rue_school its hard to keep the angles right so that the sand dosn't sheer off
08:43 rue_school I also made a little setup for making wax positives, which would have worked better if I had a vacuum chamber
08:43 Jak_o_Shadows Did you do the lost PLA method?
08:43 rue_school no, I have a problem with burning it out
08:43 rue_school I only have a really small electric furnace for it
08:43 Jak_o_Shadows Yeah, I've never thought of it as being too sucessfull.
08:44 rue_school that guy in alaska did a great job
08:44 rue_school plaster of paris sucks as an investment, lots of sulfur and it takes forever to dry
08:44 Jak_o_Shadows Yeah. I've heard it done, but it seems bad.
08:45 rue_school I started with the plaster, and then made some green sand
08:45 Jak_o_Shadows TBH, I would try for what they actually do: building up sand layers with some sort of glue-sand mix, then shove it in more sand.
08:45 rue_school water sand actually
08:46 rue_school technically they use a mix with a bit of hydroscopic oil in it...
08:46 rue_school hyrdro.... hmm
08:47 rue_school http://ruemohr.org/~ircjunk/projects/smelter/p1030995.jpg
08:47 rue_school 5 years is pretty good for that lining, I really ought redo it
08:47 rue_school http://ruemohr.org/~ircjunk/projects/smelter/p1020016.jpg
08:47 Jak_o_Shadows I wonder how flour+water make that weak glue
08:48 rue_school origionally I was playing with lost foam
08:48 rue_school you dont need glue
08:48 rue_school just the bentonite clay
08:48 rue_school once the heat hits it, it locks/hardens
08:48 rue_school http://ruemohr.org/~ircjunk/projects/smelter/p1020013.jpg
08:49 rue_school http://ruemohr.org/~ircjunk/projects/smelter/p1020009.jpg
08:49 Jak_o_Shadows A mate showed me this video the other day: https://www.youtube.com/watch?v=s9IdZ2pI5dA
08:49 Jak_o_Shadows quite cool I thought
08:50 Jak_o_Shadows Laser sintering through a 5-axis moving nozzle, with milling built in, so you can mill the 3d printed product.
08:54 rue_school nice how they go straight for the earospace market
08:55 Jak_o_Shadows The margins are just so much tighter for aerospace
08:55 rue_school its like "look, we can make a jet cone"
08:56 Jak_o_Shadows Well, you've got to show off somehow, it'd be expensive as heck
08:58 rue_school my servo library can co-ordinate 32k axies at once
08:58 rue_school (the interpolator)
09:00 rue_school wow, totally cantilivered robot arm
09:00 rue_school man, i cant do words in the morning
09:07 Jak_o_Shadows cantilevered robot arm?
09:07 rue_school yea
09:07 rue_school I'm all about counterbalanced ones
09:09 Jak_o_Shadows Oh yeah, I agree. Cantilevered limits your weight, while counterbalanced only reduces your speed, potentially. But probably less than cantilevered anyway
09:12 rue_school bbl
12:01 JT-Shop Tom_itx, thanks, when his he around?
13:35 Tom_itx JT-Shop, it's hit and miss, he's in class this week. toward evening or early morning usually
13:35 zhanx Tom_itx your alive i see
13:36 Tom_itx http://ruemohr.org/~ircjunk/projects/smelter/p1030995.jpg
13:36 Tom_itx mostly
13:36 zhanx how you feeling
13:36 Tom_itx the good half is good
13:36 zhanx nice
13:37 zhanx i am able to jog for 5 minutes now and walk / job 3 miles again
13:37 zhanx icing the knee right now from it
13:37 zhanx what did you melt down cans?
13:37 Tom_itx no that's rue's stuff
13:37 Tom_itx posted for JT-Shop
13:38 zhanx i was like not sure how he did it but sweet
17:01 Hyratel http://skyvaal.tumblr.com/post/126040142573/ultracheese-digg-when-you-find-out-your
17:19 rue_school apparently I'd not paid for lodging yet, $1500 bill...
17:48 wolfmanjm anyone ever got a PS3 game controller to work on linux? I have followed all the guides, the kernel sees it (connected via USB) but there are no events generated
17:48 wolfmanjm guess i could try bluetooth
18:00 rue_school no, xbox
18:01 rue_school you need to work out how to trick it into seeing it as an hid device
18:01 rue_school you have to add the vendor/product id somewhere
18:01 rue_school iirc
19:01 zhanx rue is right
19:29 wolfmanjm it is detected, it just does not generate any events, jstest even sees it, and xboxdrv detects it, but no events are generated.
19:45 rue_school it'll hook in as an HID device when it works and you can use gygame to access and test it
19:48 wolfmanjm yea that all works, it just not send any events
19:49 wolfmanjm it shows up as a sony PS3 controller. it is there and mapped fine it just does not send any data.
20:09 rue_school what are you testing it with?
20:09 rue_school pygame, right?
20:16 wolfmanjm no jstest
20:16 wolfmanjm and even evtest
20:16 wolfmanjm the controller is simply not sending any data
20:31 rue_school no, use pygame
21:26 rue_school orlock, it can only step the motors forward?
21:28 orlock Backwards should work too
21:28 rue_school your function only goes one way
21:30 orlock It tracks the step number
21:31 orlock increments or reduces it
21:31 orlock then steps based on that number
21:31 rue_school I noticed
21:39 rue_school orlock, are you set up to give some code a quick try?
21:43 rue_school void stepRA_Motor(int thisStep) {
21:43 rue_school dirStepRA_Motor(1);
21:43 rue_school }
21:43 rue_school dirStepRA_Motor(char dir) { // use between -1 and 1 for dir
21:43 rue_school static unsigned char phasePtr = 0;
21:43 rue_school unsigned char phaseData = {5, 6, 10, 9};
21:43 rue_school phasePtr = (phasePtr + dir) && 3;
21:43 rue_school
21:43 rue_school digitalWrite(RA_motor_pin_1, (phaseData[phase] && 0x01) != 0);
21:43 rue_school digitalWrite(RA_motor_pin_2, (phaseData[phase] && 0x02) != 0);
21:43 rue_school digitalWrite(RA_motor_pin_3, (phaseData[phase] && 0x04) != 0);
21:43 rue_school digitalWrite(RA_motor_pin_4, (phaseData[phase] && 0x08) != 0);
21:43 rue_school }
21:43 rue_school its backwards compatible
21:44 rue_school it would make more sense in C, because you can apply it to the port more efficiently
21:54 rue_school orlock, you want to poll the serial, not have it interrupt driven
21:54 rue_school you want your timers to be interrupts
21:55 orlock Theres also a more effecient command i can use for the stepper movement
21:55 orlock instead of changing speed
21:55 orlock and then changing it back
21:56 orlock it says "change speed for X duration"
21:56 rue_school I'm not that deep yet
21:56 orlock but the real problem that needs fixing
21:56 rue_school I see a few sources of timing errors
21:56 orlock is the fact the motor stops moving after about an hour due to microsecond wraparounds
21:57 rue_school I'll get to that too
22:24 rue_school aaaaaaaaaaaaaaaaaaaAAAAAAAAAAAAaaaaaaaaaAAAAAAAAAAaaaaaaaaaAAAAAAAAAaaaaaaaaAAA I NEED TO BUILD SOMETHING
22:24 e_school spins a toothbrush into the table to try to generate enough heat to do some soldering wit