#robotics Logs

Nov 23 2014

00:08 mrdata on some processors, the baud rate depends on the setting, but also on the system clock rate
00:12 rue_shop2 they are all PC's
00:13 rue_shop2 but the way you set the baud rate of a serial port under linux is a black art
00:13 rue_shop2 esp if you want to do it in the same way regardless if its a usb or 16550 port
00:13 orlock well, depends on the serial library.. oh, right ;)
00:13 rue_shop2 yea
00:13 orlock i remember dealing with setserial like, a decade ago
00:13 rue_shop2 my library is 3 years of google research
00:14 rue_shop2 nobody agrees on exactly how you set the baud rate of a serial port
00:14 orlock and eyah, it was always horrible
00:14 rue_shop2 (over about 2400 baud anyhow)
00:14 rue_shop2 and they keep defining new baud rates in the kernel
00:14 rue_shop2 I think they are all the way up to 115200 now
00:15 rue_shop2 which is the baud rate I need to set, but the call wont take that paramiter
00:15 rue_shop2 at one point I was going crazy enough to look at writing my own kernel driver for a usb serial chip
00:16 rue_shop2 I should look at how minicom does it again
00:18 rue_shop2 tho, if its like I recall I rejected it uses a library that adds 15M to your program size and uses a library chain that requires an exact set of versions of all its sublibraries and uses function calls that are undocumented and every time they upgrade the library they change the order and count of the arguments in the call to it
00:18 Hyratel asshole-obfuscation
00:18 rue_shop2 yea
00:19 rue_shop2 and they run it thru a comment stripper before they post the source...
00:19 rue_shop2 nobody could maintain code like that with no comments
00:25 rue_shop2 aha, I have labeled the arms
00:25 rue_shop2 this will help me keep track
01:38 rue_shop2 hmm
01:38 rue_shop2 first I scale, then I offset
01:38 rue_shop2 which means I'm not alwasy sure what the offset should be
01:38 rue_shop2 oh no
01:38 rue_shop2 I offset, then scale
02:55 rue_more so, the units I have beforehand dont mean much, offsetting is kinda just guesswork
03:02 mrdata offset what?
03:13 rue_more axies of my robot arm
03:13 rue_more I ahve a 'slave arm' I can use to "1:1" control it
03:13 rue_more there are a few offsets and scalings in the process
03:19 mrdata ok
07:28 septictank test
07:35 deshipu failed
07:39 septictank is it onlne
07:48 deshipu no, it's afternoon
08:08 septictank what time to online
08:12 deshipu you accidentally a verb
08:16 septictank ???
08:18 deshipu so what's up?
08:54 MjrTom !!!
10:29 Steffanx lol deshipu :D
11:15 SquirrelCZECH fuu
11:15 SquirrelCZECH well
11:15 SquirrelCZECH anybody some exp with speaker wires?
11:15 SquirrelCZECH :)
11:16 SquirrelCZECH me got speaker set, when "Second" speaker was connected with RCA jack
11:16 SquirrelCZECH and it got damaged
11:16 SquirrelCZECH so I want to resolder the jack with new one (cable to second speaker got connetor one one side and leads into speaker ...)
11:16 SquirrelCZECH buuut
11:17 SquirrelCZECH the speaker cable is not something I would expect for RCA but just two wires
11:17 SquirrelCZECH so I can't detect which should go on the GND of RCA and which should go on positive..
11:17 SquirrelCZECH P.S: second speaker is also powered via that cable
11:17 SquirrelCZECH can I somehow figure out the polarity?
11:17 SquirrelCZECH two wires: completely black, one of them got white line
12:19 rue_bed is its not a power cable the polarity does not matter
12:22 Tom_itx sure it does
12:23 Tom_itx for phase
12:23 rue_bed your prolly the only person who cares about phase
12:23 rue_bed :)
12:23 Tom_itx i always wired them the same
12:24 rue_bed how about with the same length cable so there is equal propigation delay :)
12:24 Tom_itx that too
12:30 rue_bed good show, I'm sure your sound is quite technically correct :)
12:30 rue_bed I was really surprised when I used a computer to do a freq sweep on my computer speakers
12:30 rue_bed huge dip in the middle
12:31 rue_bed so I equalized it out and everything sounded horrid
12:31 rue_bed level responce sucks?
12:31 Tom_itx heh
12:31 Tom_itx i'm more lofi anymore
12:31 Tom_itx not so much hifi
12:32 rue_bed its surprising how much music isn't even really stereo
12:34 rue_bed well, the sun is up
12:34 rue_bed ideas on making a device to track the position of the sun?
12:34 rue_bed tilt and pan photosensor in a tube?
12:35 Tom_itx my telescope will
12:35 rue_bed heh
12:35 rue_bed did you see that other blown chip?
12:35 Tom_itx i didn't look
12:35 Tom_itx which board?
12:35 rue_bed small one in the bottom right of the fpga board
12:35 Tom_itx that's what i told you
12:35 rue_bed I think its a power supply one
12:35 Tom_itx just above the header
12:36 Tom_itx the little dot on the so23?
12:36 Tom_itx i think that's supposed to be there
12:36 rue_bed it didn't have paint on it
12:36 Tom_itx there are 2 just the same
12:36 Tom_itx exact same markings
12:36 rue_bed yea, one looks ok
12:36 rue_bed other has a mountian on it
12:36 Tom_itx i looked at under the scope
12:37 Tom_itx just deeper mark than the other one i think
12:37 rue_bed do the fpga even have a 5V supply?
12:37 Tom_itx kinda hard to tell
12:37 Tom_itx i think they're 3.3
12:37 rue_bed aren't they all like 3.3 and 1.8?
12:40 rue_bed true story
12:41 rue_bed a couple are walking with their dog on a trail, they come around a corner and there is a bear, the guy throws the dog at the bear and runs
12:42 rue_bed I'm sure the bear and the dog were stunned
12:42 rue_bed bear prolly had a conversation with the dog about the company it kept
12:43 rue_bed the sun is out
12:43 rue_bed it'll be out till 2
12:43 rue_bed its 10 now
12:44 bezoka 19:24 PM here ^^
12:44 rue_bed I wont see the light of day at home till next weekend
12:44 rue_bed the cat is giving me a back massage
12:44 rue_bed hmmmm
12:52 SquirrelCZECH it's wired all nicely :)
13:23 rue_more hmmm, I'v never tried making a capacitor...
13:55 mrdata rue_more, making capacitors is fun
13:56 mrdata especially high voltage pulse rated ones
14:07 rue_shop2 hmm .33uF, not bad
14:07 rue_shop2 its about 2' of aluminum foil tho
16:19 rue_more TELunus, were you sizing a capacitor bank for an leectric vehicle?
16:19 TELunus Don't think so?
16:19 rue_more ah
16:20 TELunus I've been looking at caps for a railgun.
16:20 rue_more TELunus, how much do ya think a person could get if they turned 2 rolls of tinfoil and 2 rolls of sawran wrap into a capacitor?
16:20 rue_more oh, right, railgun
16:21 TELunus How long is a roll of saranwrap/aluminum foil?
16:21 rue_more about 100'
16:21 TELunus How wide
16:22 rue_more I know neither the diaelectric constant nor the thickness of the sawran wrap
16:22 TELunus I was going to google that.
16:22 TELunus 0.5mills
16:23 TELunus Except we should really switch to metric now, so 12.5 micrometers
16:23 TELunus 30m long
16:23 rue_more 12" wide
16:24 rue_more the sawran wrap has a U on it, thats the only thing that might be a plastic type indictor
16:24 rue_more I'm guessing about 2uF
16:24 TELunus My saranwrap is ~30cm wide
16:25 rue_more with a breakdown voltage of about ... 60v...
16:25 rue_more (my guess)
16:25 TELunus So we've got an area of 9 sqm
16:25 rue_more is that rolled
16:25 rue_more you have to account for hte double siding when its rolled
16:26 TELunus Well, if you think about it a 9sqm plate capacitor is 2 9sqm plates, we're just using both sides of the foil as our 2 plates.
16:27 rue_more so I think you should get about 18m^2 of capacitor area
16:27 TELunus Wait, no.
16:27 TELunus That's why we need 2 rolls each.
16:27 rue_more yup
16:28 rue_more polyvinylidene chloride
16:28 rue_more hah, googles autocomplete did polyvinylidene chloride dielectric constant
16:28 TELunus Nice.
16:29 SquirrelCZECH never
16:29 SquirrelCZECH ever
16:29 SquirrelCZECH I imagined
16:29 SquirrelCZECH that 3d printer airless wheel with weight 9g
16:29 rue_more ooo pp is 2700V/mil
16:29 SquirrelCZECH would be able to endure >5kg pressure
16:29 rue_more dieelctric constatnt of 2.2
16:31 rue_more TELunus, ok, I got 17.6uF
16:32 TELunus Cool.
16:32 rue_more but it would be able to take 1300V
16:33 rue_more 23J
16:34 rue_more huh
16:34 rue_more TELunus, how many joules for your railgun?
16:35 TELunus I's more a matter of current. I don't much care how long I can accelerate my projectile for, I just want to see it start moving.
16:36 rue_more unlike mine that hopped and fused to the rails
16:36 rue_more SquirrelCZECH, cool
16:37 SquirrelCZECH rue_more: yeah
16:37 SquirrelCZECH had to print another
16:37 SquirrelCZECH to ... get the right configuration :D
16:39 uirrelCZECH have to assign "microwave sound" to the printer, it would be
17:56 rue_more ok I worked on the retainer wall more
17:57 rue_more moved the solar cells for the yard lights to the top of the clothes line pole
17:59 deshipu now you can wear other closthes than transparent ones \o/
18:01 deshipu I got another one of my robots to walk http://youtu.be/uTGFulDR2lg
18:01 deshipu those servos are slow :(
18:42 GuShH deshipu: why are you blocking comments? afraid of criticism? :p
18:42 GuShH or tired of younoobers
18:42 deshipu GuShH: I yet have to see a useful comment on youtube
18:43 GuShH lol
18:43 deshipu GuShH: you can comment here if you want: https://hackaday.io/project/3301-pico-kubik-quadruped-robot
18:43 GuShH nah
18:43 GuShH deshipu: I could comment here if I wanted to!
18:44 deshipu GuShH: that's also true
18:44 GuShH deshipu: other than great job, what else can be said
18:44 GuShH also, why is youtube still the same crap, for some reason my "viewed" videos are not flagged as such
18:47 GuShH rue_more: it appears your hunch on that lathe bed was correct, I began to clean up the bed after taking the saddle, compound, etc. apart and I noticed a few grinder marks -- which makes me wonder whether something horrible happened to the poor lathe and they had to remove the bad portion out or... if that is just a left-over from a casting raiser, which on these old machines is common to find grind marks everywhere.
18:47 GuShH also, the hump on the bed is to extend the swing, you can actually remove one portion of the ways for extra swing
18:48 GuShH which is pretty neat, but those ways are quite worn.
18:51 GuShH sort of an older style gap bed
18:52 Tom_itx maybe they broke it and re'welded it
18:52 Tom_itx and it's all warped
18:53 GuShH Tom_itx: broke what?
18:53 Tom_itx just speculating
18:53 GuShH no, rue complained about the bed being too short
18:53 GuShH I was just commenting on how the front of the ways can be removed
18:53 Tom_itx well he just likes to do that
18:53 rue_shop2 seen the gap beds before
18:53 GuShH it uses two pins to locate and a nut/bolt to hold down
18:54 GuShH rue_shop2: you migt be talking about sliding gaps, this is a fixed gap
18:54 rue_shop2 I dont recall actually complaining it was short, maybe commenting that it was odd
18:54 ShH sh
18:54 Tom_itx see, he cooked his reprap so to make him feel better i fried my cnc control boards
18:54 rue_shop2 nope a section under hte head that comes out
18:54 GuShH yes
18:54 GuShH Tom_itx: huh?
18:54 GuShH sorry to hear
18:54 GuShH rue_shop2: however I've yet to attempt to remove the section, I might try that for cleanup
18:55 GuShH wonder how well it will locate again, I bet not very well. such primitive crap
18:55 Tom_L http://tom-itx.ddns01.com:81/~webpage/rue/7I43.jpg
18:55 Tom_L http://tom-itx.ddns01.com:81/~webpage/rue/7I47.jpg
18:55 GuShH the tailstock has been repaired before, but I'll fix that one of these days, I was bored today so I worked a little on it. have no need for that thing, but I want to see it restored now
18:56 GuShH first time I see a solid spindle
18:57 GuShH it would be a good candidate for metal spinning
18:58 ace4016 what's the blue goo for Tom_L?
18:58 Tom_itx i dunno, it came that way
18:58 GuShH lol
18:58 ace4016 heh
18:58 Tom_itx maybe to mark original chips?
18:58 GuShH I think it might just be smurf blood
18:58 anonnumberanon Hey Loshki
18:58 Tom_itx lower right on that one by the headers is blown
18:59 GuShH yeah I see the bulge
18:59 GuShH pop!
18:59 ace4016 looks like an FPGA board?
18:59 Tom_itx yup
19:00 ace4016 ah, reading up...is that your CNC control board? :P
19:00 GuShH was
19:00 anonnumberanon I have been learning vhdl for fpgas. But I still don't get the point of using an fpga. All these microcontrollers abound.
19:00 Tom_itx faster
19:00 Tom_itx parallel processing
19:01 Tom_itx overall kick ass
19:01 ace4016 you can technically get an ASIC that does a better job
19:01 ace4016 but...
19:01 ace4016 they're generally good at what they're designed to be good at only
19:02 anonnumberanon How can I like, get an fpga for projects, and should I ?
19:02 ace4016 FPGAs are more flexible
19:02 anonnumberanon over something like an ATMEGA328p
19:02 ace4016 Xilinx, Altera, and a few others have FPGAs/FPLDs/etc. that you can use with tooling and all
19:02 ace4016 depends anonnumberanon
19:02 Tom_itx hardly a comparison between a mega328 and a fpga
19:03 anonnumberanon OUr vhdl teacher just gave us a huge fpga dev board today, it has like everything on it.
19:03 anonnumberanon An Altera branded one.
19:03 anonnumberanon For us to play with.
19:04 Tom_L http://tutor.awce.com/wpv-1.htm
19:04 Tom_L start playing
19:05 Tom_L http://www.asic-world.com/verilog/veritut.html
19:05 Tom_L http://www.xess.com/projects/
19:10 anonnumberanon so you're just telling me to learn Verilog ehh?
19:12 ace4016 learn either or both? :P
19:12 anonnumberanon wer learning Verilog in a few weeks as well
19:12 Tom_itx quite similar
19:13 Tom_itx once you learn your first language the next 10 are easy
19:14 anonnumberanon heh yeah
19:15 anonnumberanon I'm going quite hardmode on C presently
19:15 anonnumberanon With K&R
19:21 Tom_itx 2nd edition?
19:21 Tom_itx you need that one for the joke
19:22 Red_Onyx how much do you think that Altera FPGA cost?
19:23 ace4016 which one?
19:23 ace4016 the studend dev boards or so are usually $100-$500
19:23 Red_Onyx the altera one, anonn gfot it from a teacher
19:23 ace4016 ah
19:23 anonnumberanon oh
19:23 Red_Onyx I have seen some really expensive FPGAs
19:23 ace4016 they can be
19:23 anonnumberanon he said a few hundred bucks, it looks like it's at least a few years old
19:24 Red_Onyx oh
19:24 ace4016 don't need anything too fancy either for a beginner though
19:24 anonnumberanon if i had a list of them I'd be able to find it from memory, my colleague is holding it right now
19:24 ace4016 the expensive stuff has some impressive clock speeds and such
19:24 anonnumberanon That one has a 50 Mhz oscillator though I rememnber that.
19:25 anonnumberanon Actually I'll try to find it hang on.
19:25 anonnumberanon Tom_itx, 2nd edition yeah. I don't knwo why it's a joke though heh.
19:25 anonnumberanon Although the hardness of the exercises is kind of a joke. It's pretty hard-mode.
19:27 anonnumberanon Also he lent me a book called Numerical Analysis, third ed, by Burden and Faires
19:27 anonnumberanon Cause it can teach to do integrals and differentiation using other numerical methods.
19:27 anonnumberanon It's kinda neat.
20:51 rue_more I have a pile of fpga's from stripped equipment
20:51 rue_more on boards
20:51 rue_more but I dont have a programmer
21:11 Tom_itx well, the chips are off of one board at least
21:15 Hyratel what are you scraping?
21:16 Hyratel I need to re-cap a large stereo
21:16 Hyratel but all the interconnects are wire wrap
21:16 Hyratel which is ... not easily undone. it has I think 1/8" posts with 18 or 20 awg wire
21:17 Tom_itx fixing: http://tom-itx.ddns01.com:81/~webpage/rue/7I47.jpg
21:17 Tom_itx http://tom-itx.ddns01.com:81/~webpage/rue/7I43.jpg
21:17 Tom_itx and that one
21:18 Hyratel pic1 it looks like U2 is failed, and pic2, U9?
21:18 Tom_itx u2 u3 u6
21:19 Tom_itx and u9 on the other one
21:19 Hyratel shiiit
21:19 Hyratel what happened to those
21:19 Tom_itx if i knew...
21:19 Hyratel you'd know who to gooberslap?
21:20 Tom_itx me i suppose
21:20 Tom_itx but i have no clue what caused it
21:21 Tom_itx http://tom-itx.ddns01.com:81/~webpage/cnc/psu/control8.jpg
21:21 Tom_itx probably one of those wires
21:25 Hyratel whazis
21:26 Hyratel looks like an industrial controller of some sort
21:26 Tom_itx cnc control for my sherline
21:26 Tom_itx beefed up a bit
21:33 rue_more I'm telling tom that the ground got pulled up between the pc and the cnc machine, but there is no word on evidence yet
21:33 rue_more Tom_itx, you still havn't told me if they were on the same power supply
21:37 Tom_itx pc has it's own
21:41 Hyratel ground got pulled up whuyhuh?
21:41 rue_more aha
21:41 rue_more so the neutral could have come off one of them
21:42 Tom_itx i seriously doubt that's what happened
21:42 rue_more if one of the two power supplies lost the neutral, it goes thru the signal parts between the equiptment
21:42 rue_more I think thats exactly what happened
21:42 rue_more and my proof is when you put all the equipment back in and it blows up again
21:42 rue_more for no reason
21:42 Tom_itx signals are the only connection from the pc thru the parport
21:43 rue_more yea
21:43 rue_more one side loses its neutral, and so the current path geso from the 120V hot thru the signal path, and to the ground/neutral of the equip on the other side
21:44 Tom_itx pretty sure at least 2 or more have gnd wires on them too
21:44 Tom_itx i recall hearing something short in the control box
21:50 Tom_itx rue_more, you're saying i need a better ground between the two?
21:51 rue_more no, you need to find out what neutral failed
21:52 Tom_itx with all that ratsnest of wires what makes you so confident that is the problem and not one of the wires in the box?
21:55 rue_more because you said you didn't do anything that could have caused it and everything was at the right votlages
21:55 rue_more and I think your right
21:55 rue_more I dont think you made a single mistake
21:55 rue_more I think this was a neutral failure and a coinncodintal timeing
21:55 rue_more and I think that whatever neutral failed will do it again
21:55 rue_more have a plug tester?
22:06 Tom_itx huh?
22:07 Tom_itx i have a meter
22:07 Tom_itx oh for 120v?
22:07 Tom_itx yeah somewhere
22:17 rue_more no, a tester with 3 lights that do a delta between the hot, neutral, and ground
22:18 Tom_itx yeah i got one somewhere
22:18 Tom_itx it's just an outlet plug if that's what you mean
22:20 Tom_itx i did that to the whole place when i put the basement in
22:20 Tom_itx some of the old wiring was wrong
22:20 Tom_itx all fixed
23:20 rue_bed your not really hearing what I'm saying
23:20 rue_bed but if they are off thie same outlet, it helps narrow things
23:20 rue_bed do they go into a power bar? or they seperate plugs on the same outlet
23:30 rue_bed Tom_itx, if the 120V neutral gets disconnected from a computer, where does the current go?
23:34 rue_bed I have had it happen twice to me