#robotics Logs

Sep 29 2012

00:49 rue_house you made a servo control howto right?
00:49 rue_house can I steal images from it?
00:49 rue_house its for the good of the world, really
01:20 rue_house http://hackadaycom.files.wordpress.com/2012/09/analysis-of-4-digit-pin.png
01:20 rue_house ahhahahaaha
04:44 wizzbrah http://hackadaycom.files.wordpress.com/2012/09/analysis-of-4-digit-pin.png
04:44 wizzbrah I'm really wondering what is wrong with 5678
04:44 wizzbrah or 4567
05:02 wizzbrah http://hackadaycom.files.wordpress.com/2012/09/analysis-of-4-digit-pin.png
09:30 AuroraX does anyone familiar with LonTalk here?
10:03 rue_bed not i
13:03 rue_shop4 or i
15:02 rue_shop4 heh, I brushed the plastic case4 with my solding iron and the smell of the burning plastic gave me memories of my early days soldering
15:15 rue_shop4 oops I made a chromatic error
15:15 rue_shop4 I was supposed to use the grey and red wire for th left and right
15:16 rue_shop4 instead of red I picked up and did a bunch with the blue
15:42 rue_shop4 ok 16 inputs are wired to DC filters
15:44 home rue_bed: Why?
15:44 home I mean rue_shop4
15:44 home rue_shop4: Why do you ahve 3 irc accounts?
15:51 tsmeow-afk flipped on the tv and saw football game, and made some improvements: find a loophole where it's permissable to have a team member in the touchdown zone when the ball is hiked, embed a one-time-use very-high-speed throwing arm into the QB's padding, throw the ball at 400mph to the touchdown
15:52 theBear he's got a creative accountant
16:03 tsmeow-afk picks up stuff and throws it at the bear ,,, avrs, packs of 2000 leds, psu regulators, lan cab
16:38 jschall i've been spending a lot of time trying to work this out: a plane flying in wind with a constant rate of turn has a path that looks like this: http://imgur.com/wPdCL - i'd like my plane to fly a perfect circle relative to the ground (rather than relative to the airmass). given a known: wind vector, airspeed, ground speed, heading, and a given turn radius, how can i compute an instantaneous rate of turn to make it fly a perfect circle?
16:38 jschall i have written a simulator to play with this, and i've gotten nowhere for days
16:44 tsmeow-afk notes a tornado would make the rotating mass of air over a fixed p
16:46 katsmeow-afk what if your plane remembers the over/undershoots during banking against/into the wind, and each time makes a correction in it's predictions of what it should do to maintain the desired path?
16:47 katsmeow-afk you will need to establish acceptable error gradients in the plane's path to avoid excessive corrections
16:48 katsmeow-afk and some things like variable passing downdrafts and hitting birds, you cannot program for in advance very well
16:49 katsmeow-afk ditto fuel flow, loss of engine, engine power variations with temperature and humidity, etc etc
16:50 katsmeow-afk afk
17:02 jschall katsmeow-afk: i want to model it mathematically, rather than use control to guess it.
18:37 tsmeow-afk thinks you may learn to drive a car with some fixed procedure, you build in variability for unforseen situations, like wind gusts and wrecks in front of you,, and that's not called gues
18:37 katsmeow-afk unless yu are, then i wanna not be around when you are driving
18:49 katsmeow-afk the plane can make millions of calculations in the time the plane flies a foot, and the variables in the equations are bounded by previous results, and the acceptable output is bounded by the desire to minimise the rror off the ideal flightpath
18:49 katsmeow-afk it's not a wild assed guess
18:51 katsmeow-afk additional bounds are the current flight characteristics , the limits of the plane's reactions , and the limits of the cargo
18:52 katsmeow-afk cargo limit might be : the camera and antenna cannot pan-tilt past x degrees, so don't bank the airframe past x degrees
19:04 katsmeow-afk i am reminded of a rule no one made : do not roll a B-52H 90 degrees so the wings are vertical, and then try to fly it in a straight line 500ft off the ground
19:05 katsmeow-afk or another one : do not bring a KC135 to a complete stop, zero airspeed, 50ft off the ground at the end of the runway
19:06 katsmeow-afk or : do not barrel roll a 727 , altho everyone survived that one
19:06 katsmeow-afk or : do not fly your helicopter upside down (altho it's possible in rare situations)
19:07 katsmeow-afk or : if you rotate a helo past a certain angle when it's on the ground, the blades wear out real fast
19:08 katsmeow-afk the pilots wer not programmed with the missing rules, and they guessed wrong, if they ever did learn from history, they did so too late
19:09 katsmeow-afk i suspect the guy who landed the B2 wheels up did so on purpose, what with a copilot and lots of warning gear to tell him not to do that
19:11 katsmeow-afk a few yrs ago, there was video of the wings breaking off a 135 water dump forest fighter plane, my first reaction as it was happening was "i bet no one learned from that happening in ww2, and no one installed auto-ejection seats in that plane"
19:12 katsmeow-afk there's a video of a ww2 unwritten rule being broken: one bomber dropped several bombs thru the wing of the plane below it, the wing separated, the plane dropped exactly the same way
19:13 katsmeow-afk wings coming off it's all that unusual, but there's not a lot of video of it happening
19:13 katsmeow-afk i'd make a rule : if the wings come off, parachute the humans out
19:14 katsmeow-afk even with ejection seats, a plane can be moving such that the pilot cannot activate it
19:15 katsmeow-afk the F35 cuts off the pilot's oxygen, the pilot passes out, they cannot fire the ejection seat, they die
19:16 katsmeow-afk wings coming off it's NOT all that unusual,
19:22 katsmeow-afk "if i catch you trying to fly a plane fuselage with no wings on it, i'll demote your ass so fast,, damnit you are not certified to fly the individual pieces of an airplane!"
19:27 katsmeow-afk before ww1, there was no rule about touching an airplane while it was flying, so the idea came about to hang thin wires from balloons, the pilots didn't have this rule, they wrecked a lot of planes hitting those wires
19:28 katsmeow-afk so the rule was made: while you are in control of this aircraft, you will not allow it to touch wires, poles, other aircraft, mountains, bullets, or missiles
19:29 katsmeow-afk the part about the bullets was added AFTER the first machine guns were added to shoot between the blades of the single engine prop planes, you can prolly guess why
19:32 katsmeow-afk oddly, the Cuba debacle was a case of not learning that, the fighters the usa flew could go faster in afterburner than the bullets they shot, so the filled the air in frontof the jets with lead and then ran into the bullets at supersonic speeds,, tsk tsk, touching the bullets while flying, ripping holes in the planes is what they did
20:29 rue_house kat, finished the audio switch, no noticable dropoff at high freq
20:29 rue_house I swept it
20:30 katsmeow-afk k
20:31 katsmeow-afk males often cannot hear to 20khz anyhow, there's a male dj on one fm station here that rolls the high end down so much that his desk sounds like a telephone
20:40 rue_house I stop at 15k
20:40 m_itx won
20:41 katsmeow-afk the roll off will be above that
20:41 katsmeow-afk it's based on whatever the capacitance of the fets is and the drive resistance of the source
20:41 katsmeow-afk a classic low pass filter
20:42 tsmeow-afk waves hi to
20:44 Tom_itx hi kat
20:51 rue_house if the freq rolloff is above my ability to hear, I'm not worried
20:51 Tom_itx what did we do today?
20:52 rue_house no robotics today, he couldn't show up
20:52 Tom_itx so you're down to one?
20:53 rue_house that was the one
20:54 Tom_itx so what did rue_bed rue_house rue_shop4 et others get done today?
21:12 rue_house finished the audio switch
21:12 rue_house just hooked up the gear, but there is an intereting noise problem
21:15 rue_house its not 60hz
21:15 rue_house i sounds like a 120hz sine
21:19 katsmeow-afk 120hz = full wave rectified 60hz
21:20 katsmeow-afk didja use big filter caps?
21:20 rue_house its comming in from the modified tape deck I use as a mic preamp
21:20 katsmeow-afk o
21:21 rue_house it persists even if I pull the power from the deck
21:22 katsmeow-afk flourescent lites?
21:22 rue_house nope
21:22 rue_house no power to the deck
21:22 katsmeow-afk i mean in the room anywhere
21:22 rue_house comming in on the signal line
21:22 rue_house no
21:22 rue_house I can select another channel and it goes away
21:22 Tom_itx poor ground?
21:23 rue_house the tape deck has no ground
21:23 katsmeow-afk unplug from deck, short the input cable at the far end, see if it still hmmmms
21:23 rue_house it dosn't
21:23 rue_house erp wait
21:23 tsmeow-afk waits before saying "carpy ca
21:24 rue_house if I short the input I get it
21:24 katsmeow-afk if it does not hmm, then gnd the chassis of the tape deck, it's acting like an antenna out there
21:25 rue_house no tape deck involved
21:25 rue_house if I short the input to the channel selector, it 'generates' this tone
21:25 katsmeow-afk short it to what?
21:25 rue_house signal to ground on the selector input
21:26 katsmeow-afk oh,, your input jacks are chassis gnd and your 4066's are not?
21:26 rue_house I used a ground star
21:26 katsmeow-afk run a gnd from chassis jacks to the input dc block pcb and to the fet pcb gnd
21:27 rue_house everything goes out from the star
21:27 Tom_itx a falling star?
21:27 rue_house I didn't check how smooth the outputs are of the dc-dc maybe I need more caps
21:30 katsmeow-afk yu can also do [switcher] --50ohm -- 1000ufd -- electronics ,, or whatever ohms works for you
21:30 katsmeow-afk or
21:30 katsmeow-afk yu can also do [switcher] -- diode -- 1000ufd -- electronics
21:30 rue_house I'm thining about this
21:31 katsmeow-afk my Yamaha has 100 ohm resistors on all pwr inputs to all channel pcbs
21:31 rue_house power noise shouldn't matter
21:31 katsmeow-afk ok
21:31 rue_house because its just bias voltage for the switches
21:32 rue_house so, if a channel is shorted
21:32 rue_house there becomes a potential difference between its output and ground at the other end
21:32 rue_house ground ---- cap ----*----- fet ----- output
21:33 rue_house * -----/\/\ 474k \/\/\--- gnd
21:33 katsmeow-afk you are running no LED displays? no ttl chips?
21:33 rue_house leddisplay with 1 ttl chip, but no changing states
21:33 katsmeow-afk oh, lol
21:34 katsmeow-afk you sure your fet -5 isn't being connected to the fet chip analog inputs?
21:34 rue_house if there were noise between the gnd of the 470k and the ground of the output
21:35 rue_house thats the same path between the switching power supplies and ground
21:35 katsmeow-afk 470k is aweful high
21:35 rue_house yes, its just to kill dc
21:35 katsmeow-afk * -----/\/\ 474k \/\/\--- gnd <<== sure that gnd isn't -5v ?
21:35 rue_house it turns out I missed by a pin and I switched 5V to the output, the PC speakers I was testing with had no dc filter and one side amp is blown
21:35 rue_house its gnd
21:36 katsmeow-afk k
21:36 rue_house its off the star
21:36 rue_house I
21:36 rue_house 'kll sjhsw
21:36 rue_house I'll show
21:36 rue_house keyboard problems
21:36 katsmeow-afk remove cats from keybd
21:40 rue_house http://eds.dyndns.org/~ircjunk/projects/audioswitch/p1040635.jpg
21:40 rue_house ground star is just right of the blue cables
21:41 rue_house bottom baord is controller
21:41 katsmeow-afk what's the coiled wire?
21:41 rue_house top board is dc block
21:42 rue_house the black or the stuff at the bottom right
21:42 rue_house or ontop of it
21:42 katsmeow-afk to the right of the dc block pcb
21:42 katsmeow-afk 1x3 pcb
21:42 rue_house all the black wires go to the ground stay
21:42 rue_house there is a spring on the middle of the ground star that grounds the lid
21:43 rue_house as there is a green wire that grounds the bottom plate
21:43 katsmeow-afk k, but it still is not a star gnd, your pwr lines don't go there,
21:43 rue_house good point
21:44 katsmeow-afk put the pwr lines there with the big filter caps there too
21:45 katsmeow-afk you can star the audio lines all you want, but if the fet bias is bouncing around, the fets will transfer it to the signals
21:45 rue_house but the fets are dc
21:46 rue_house what is the origin of the ac
21:46 rue_house I think I'll go scope the dc-dc outputs
21:46 katsmeow-afk the psu
21:46 rue_house its the only possability
21:46 katsmeow-afk scoping it should be the first thing you did
21:46 rue_house ah, you know what
21:47 rue_house I forgot a filter cap on the -5V
21:47 katsmeow-afk gnd the scope to the star pcb
21:47 katsmeow-afk oh
21:47 rue_house ok I'll go cap the hell out of it, and then scope it
22:00 rue_shop4 wow
22:00 katsmeow-afk hmm?
22:00 rue_shop4 the -5v is really noisesy
22:00 rue_shop4 and persistant
22:00 tsmeow-afk
22:00 rue_shop4 I'll ahve to make a power filter board
22:00 rue_shop4 50mv sawtooth
22:00 tsmeow-afk nods some more on the way to being afk and
22:06 rue_shop4 hmm maybe if I go stright for the iron
22:06 rue_shop4 forget ferrite
22:18 katsmeow-afk idiot radio station has the compressors set to completely cut off the audio every time there's any bass, and they have the bass boosted, so every time the drummer hits the big drum, there is no sound, i mean all the audio is cut off
22:18 katsmeow-afk the music is pulsing at ~2hz, it's intolerable
22:33 rue_shop4 ----/\/ 1R\/\/--*--1000uF electrolytic to gnd *---/\/\ 1R \/\/\---*---- 100uF tant to gnd *---\/\/\ 1R \/\/\----*---2000uF low esr elec to gnd *---- output
22:33 rue_shop4 pls tell me nothing found live thru that
22:33 rue_shop4 could live thru that
22:35 katsmeow-afk wow, lots of caps there
22:35 katsmeow-afk star gnd them ;-)
22:47 rue_shop4 its quiet after the first filter
22:47 rue_shop4 so by the third one its like a wind free lake
23:05 rue_shop4 yay! 3 ohms didn't make a difference to the resultant voltage under load
23:06 katsmeow-afk shouldn't have
23:06 katsmeow-afk 3 ohms vs the low esr of a big cap makes a difference to the psu noise tho
23:08 rue_house wtf
23:08 rue_house ARG
23:08 katsmeow-afk ?
23:09 rue_house still does it
23:10 katsmeow-afk lower the 470k to 47k
23:10 rue_house I think I'v had enough of this project for tonight
23:10 rue_house its only when singla is gronded that the noise comes up
23:10 rue_house '
23:10 katsmeow-afk where is the gnd point for the resistors on the dc blocker?
23:11 rue_house that peice of pcb
23:11 rue_house this is probably becuase I grounded it to power ground
23:12 rue_house see the big green wire?
23:12 katsmeow-afk yeas
23:12 rue_house http://eds.dyndns.org/~ircjunk/projects/audioswitch/p1040635.jpg
23:12 rue_house thats line ground
23:13 katsmeow-afk you could try lifting the gnd, but i'd still wonder why you get hm when gounding an input if you truely have a good gnd system
23:15 rue_house lifting it works
23:16 rue_house !???!?!?!?!?!
23:16 rue_house there must be noise on my ground
23:16 katsmeow-afk *all* pwr lines are noisey
23:16 katsmeow-afk pwr with flourescents can be horrible
23:17 katsmeow-afk the gnd included
23:18 rue_house grrr
23:18 rue_house anyhow
23:19 katsmeow-afk what can i say? some pro equipment comes with gnd lift switches
23:20 rue_house and I'm ure the studios have a seperate ground system that uses large guage wire
23:20 katsmeow-afk you can try a couple thngs, back-to-back 5v zeners, high value resistor, dc choke, etc
23:20 katsmeow-afk yeas
23:20 katsmeow-afk stages do not however
23:21 rue_house how many turns do you lock the tape on with your Reel2reel
23:22 rue_house http://eds.dyndns.org/~ircjunk/projects/audioswitch/p1040642.jpg
23:22 rue_house it came out a nice little unit
23:22 katsmeow-afk turns to lock tape on?
23:23 katsmeow-afk nice
23:23 rue_house :) now I need to add a VU meter
23:23 katsmeow-afk 2 meters, it's sterio
23:23 rue_house !!
23:23 katsmeow-afk don't want one side to get jealous
23:23 rue_house gee, I'm just using one turn
23:24 katsmeow-afk what are you talking about with turns to lock tape on?
23:26 rue_house you have to give the take a few turns to keep it on the reel
23:26 rue_house when you thread it
23:27 katsmeow-afk ah, one, you pull it into one of the lil hole-slots, and give it one turn, and it's good
23:27 katsmeow-afk i thread it before it gets to the takeup
23:29 tsmeow-afk ponders memory s
23:30 katsmeow-afk i can use 36bit addressing to access up to 68 gigabytes, but lets think even bigger: what if i wanted to addesss bytes on the harddrives as if they were memory bytes?
23:30 rue_house maybe I can think on how to get my preamp down to 1U
23:31 rue_house katsmeow-afk,
23:31 katsmeow-afk hmm?
23:31 rue_house make each address a sector of bytes
23:31 rue_house reads 1 - 1024 yeild successive bytes
23:31 rue_house for that sector
23:31 rue_house then you have 68000 gigabytes
23:32 katsmeow-afk i know that part
23:33 katsmeow-afk 44 bits would address every byte i have atm, but considering the pata address is 48 bits wide, why not go with that instead of lopping off 4 bits to make 44 bits?
23:34 katsmeow-afk if i ask the hd controller for file blahblah, and it says it's at address 23845602365023562340 , then i can ask what is the value of byte 23845602365023562345
23:35 rue_house at what point random access to individual bytes not make sense
23:35 katsmeow-afk the 48bit memory would be hds, which are still faster than some serial ram, and main memory would be the actual mobo ram
23:35 rue_house if your going 64 bit, go 64 it
23:35 katsmeow-afk actually, i want 8bit
23:35 rue_house ok
23:35 katsmeow-afk but bigegr addresses
23:36 rue_house like the 4040
23:36 katsmeow-afk who?
23:36 rue_house er wait, it had really funny addressing
23:36 rue_house the 4040, pre 8080 pre 8088
23:36 katsmeow-afk o
23:37 katsmeow-afk there's been other processors with different sized data and address busses, even the 8086 has 21 address and 16 data
23:37 rue_house the levels off this deck are pretty low
23:37 katsmeow-afk or 20 address
23:37 rue_house then again, these tapes are 50+ yrs old
23:37 rue_house 50?
23:37 rue_house hmm
23:37 katsmeow-afk maybe recorded low, old feric tape saturates easy
23:38 katsmeow-afk metal tapes have superb responce, better than chrome even
23:38 rue_house if I'd used a lcd screen and added a usb port, I could name each channel
23:38 katsmeow-afk they are hard on heads tho
23:38 rue_house I'v seen a steel wire machine
23:38 katsmeow-afk why a usb port? just put a avr into it
23:38 rue_house touched it even
23:38 katsmeow-afk me too
23:39 katsmeow-afk recorded on it :-P
23:39 rue_house :)
23:39 rue_house I got some of the tangled wire for free
23:39 katsmeow-afk had a tube vu meter
23:39 rue_house tube?
23:39 rue_house how did they do that
23:39 rue_house or as a preamp
23:40 katsmeow-afk yeas, it was like a mini scope tube, but only one grid to throw the beam onto the area to indicate a strong signal
23:40 rue_house I cant find my old tube book :(
23:40 rue_house oh, with the tiny little screens on the end
23:40 rue_house COOOOL
23:41 rue_house did they put a scale over the front?
23:41 katsmeow-afk called them magic eyes, for some wierd reason
23:41 katsmeow-afk i don't remember one
23:41 rue_house sngle axis deflection?
23:41 rue_house soryy, this keybaord is getting bad, keys aren't going down when I put the presure I should have to on them
23:42 katsmeow-afk http://www.antimath.info/electro/vu-meter-em84/ <<== magic stripe vu tube
23:45 katsmeow-afk http://www.magiceyetubes.com/
23:46 katsmeow-afk http://www.magiceyetubes.com/patterns.htm has animations of them working
23:51 rue_house oh, I have one of those on a cap tester
23:52 rue_house one of the end ones
23:52 rue_house EM800 is the stuff to get!
23:52 tsmeow-afk
23:53 e_house tret
23:53 rue_house I have to tear the keybaord apart again and lube it
23:53 rue_house maybe take the pressure washer to it
23:53 rue_house no, I dont want to lose and keys
23:54 e_house watches the tape go ar
23:54 rue_house oh I have these 4046
23:54 rue_house think I can make an FM audio carrier with a 15Khz bandwidth?
23:55 katsmeow-afk i think it is impossible to keep a clean keybd, i have tried everything from lubricants, ammonia, pine sol, clorox, potions and sprays, and in a month it needs a severe cleaning again
23:55 rue_house make some wireless headphones
23:55 katsmeow-afk i never use the number keypad, it gets grungy first
23:55 rue_house I think its been 2 years since I serviced this one
23:56 katsmeow-afk you can make a fm carrier do anything
23:56 rue_house but can I make fm with a 4046 with a 15khz bandwidth
23:56 rue_house one for a voltage -> freq, one for freq->voltage
23:56 katsmeow-afk i'd make a transmitter for on a blank spot on fm dial, and get a tiney rado and fasten to the headset
23:57 rue_house mmm
23:57 rue_house I have one I made form a kit
23:57 rue_house but the crystal for NA stereo spacing is wrong
23:57 rue_house there is a mod I cant remember
23:58 katsmeow-afk the channels for NA FM sterio are not broadcast in sterio
23:58 rue_house I took the automatic wire stripper all apart today and serviced it
23:58 katsmeow-afk they are sent as mono with the 19khz modulated as the difference
23:58 rue_house the muxing or whatever it is, its wrong
23:59 katsmeow-afk however, there's also a subcarrier above 19khz at 38Khz, and muzak or radio paging was carried at 67khz
23:59 rue_house I need a transmission amp for channel 3 tv