#robotics Logs

Nov 04 2013

00:00 evil_dan2wik defaultro, Still on the camera trolley?
00:00 defaultro yup :)
00:00 evil_dan2wik :P
00:00 defaultro i'm trying to make it really good
00:01 defaultro current motor is heating up when I want it in angled position
00:01 defaultro but when flat, it's fine
00:01 defaultro I want to do some videos where camera goes bottom to top or vice versa
00:01 Triffid_Hunter defaultro: stepper motor will always be warm when it's holding, can't stop that. at least with a proper driver you can choose exactly how warm it gets
00:01 defaultro yup Triffid_Hunter . I think the current motor I have isn't 12v
00:02 Triffid_Hunter if you want it to run cold, put a worm gear servo on instead of a stepper
00:02 defaultro With that new one I bought, I hope it will be better
00:02 defaultro I was thinking about that too
00:02 Triffid_Hunter and/or add a spring to take most of the weight
00:02 defaultro first time i've heard that. how does it work?
00:02 evil_dan2wik defaultro, Getting warm is normal.
00:02 defaultro it's not warm. It's very hot
00:03 evil_dan2wik hmm.
00:03 defaultro i have to remove my finger in 1 second
00:03 evil_dan2wik Did it get hot when using the arduino stepper library?
00:03 defaultro yes
00:03 evil_dan2wik ok.
00:03 defaultro i looked at the library and it doesnt' send a LOW after it's rotated
00:04 defaultro i added it manually and it didn't get hot anymore but there is no more brake
00:04 evil_dan2wik defaultro, the LOW is the brake.
00:04 Triffid_Hunter defaultro: of course not.. like I said several days ago, that's *how a stepper works*
00:04 defaultro i added a digitalWrite(CoilA..B, LOW)
00:04 Triffid_Hunter evil_dan2wik: not on unipolar, all low = motor turns off
00:04 defaultro oops, Coils A to D
00:04 evil_dan2wik sorry, the HIGH is the brake.
00:04 defaultro yes, HIGH is the brake
00:05 defaultro so I am thinking that once I use the 12v motor I bought, it won't get as hot as this one I have
00:05 evil_dan2wik If you are worried about over heating, Drive the motor lower.
00:05 defaultro what are your thought folks?
00:05 defaultro that's what I thought too
00:05 evil_dan2wik Probably will get hot, not as much though.
00:05 defaultro that's why I bought a buck converter
00:05 Triffid_Hunter you bought a 12v bipolar and plan to drive it from A4982?
00:06 defaultro maybe Triffid_Hunter
00:06 Triffid_Hunter oops, should have got a really low voltage one
00:06 Triffid_Hunter like 2v, because A4982 and friends are smart current-mode drivers
00:06 Triffid_Hunter and they work best with some headroom
00:06 defaultro I did see one at 2.8v but it eats like 1.7A
00:07 defaultro if I go outside with a 6800 battery, it won't last long
00:07 evil_dan2wik defaultro, There is the option of cooling your stepper motor.
00:08 defaultro how?
00:08 evil_dan2wik its probably only at 60C right now.
00:08 defaultro I actually saw another product. It's called stepper motor brake
00:08 evil_dan2wik I would not worry unless it starts melting.
00:08 Triffid_Hunter defaultro: heh, A4982 also acts as a buck converter so when it's pushing 1.5A into your 2v motor, it will only take about 300mA from your supply
00:09 defaultro cool
00:09 Triffid_Hunter evil_dan2wik: 1s is closer to 80-90c I think, something happens to the magnetics at that temp from memory
00:09 defaultro do we have a table for that?
00:09 defaultro Today, I added 6k resistor before the TIP122
00:10 defaultro it took longer for motor to get hot. I thought it was fix but it wasn't, hehehe
00:10 evil_dan2wik Triffid_Hunter, at 90C, i burnt myself on my laptop's heat vent in 1 second.
00:10 defaultro so maybe 2 seconds
00:10 defaultro but i am sure, not more than 2 secodns
00:11 evil_dan2wik defaultro, some small heat sinks with thermal sticky pads might help cool it.
00:11 evil_dan2wik will*
00:11 defaultro i have a big heatsink connected to it
00:11 evil_dan2wik Get a small 0.5 watt fan?
00:11 defaultro I actually have a cpu heatsink with fan, LOL
00:11 defaultro but it's heavy
00:12 GargantuaSauce_ the real stepper driver will help lower the waste heat immensely
00:12 defaultro ok
00:12 defaultro this new stepper motor I bought only sucks 0.4A
00:12 Triffid_Hunter well the heat/torque ratio is basically fixed for a given motor...
00:13 evil_dan2wik no.
00:13 Triffid_Hunter so if you need same torque but less heat, you'll need a motor with lower winding resistance and higher torque rating
00:13 defaultro Triffid_Hunter: please explain the spring
00:13 evil_dan2wik If you blow the motor up, it changes.
00:13 Triffid_Hunter defaultro: if the spring holds 80% of the weight, the motor only needs to supply the other 20%, so you can run it cooler and it won't skip
00:14 defaultro next motor I want to buy is gear stepper motor. But what if want to speed up the dolly, what is the solution to it?
00:14 GargantuaSauce_ well it means he'll easily be able to adjust the tradeoff instead of having to swap out resistors like a barbarian
00:14 defaultro so spring will be like a thread hanging down and dolly is attached to it?
00:15 GargantuaSauce_ hell even a counterweight would do wonders
00:15 defaultro just like old elevators
00:15 GargantuaSauce_ and new ones :V
00:15 defaultro oh, they still do. wasn't aware
00:16 evil_dan2wik What, you really want a stepper motor on an elevator to sit there holding all the time?
00:16 defaultro looks like worm gear is nice but I am not sure if I can make dolly move faster
00:16 evil_dan2wik defaultro, Does the motor have to be on the platform?
00:16 defaultro it will be on the dolly/slider
00:17 evil_dan2wik Does it have to be
00:17 evil_dan2wik ?
00:17 defaultro it can be used without the rail
00:17 defaultro but ideally when making a timelapse, it would be nice if it's on the rail
00:17 Triffid_Hunter defaultro: power = torque * angular speed. if you want fast AND strong, you can't escape needing a more powerful motor
00:17 Triffid_Hunter defaultro: so while you're learning, reduce the power requirement as much as possible- use springs or counterweights so the motor only has to move things around, not hold them in place too
00:17 defaultro Triffid_Hunter: got it. So looks like I need 2 types of motor for 2 types of applications
00:18 GargantuaSauce_ well if you have an adjustible counterweight, its performance when angled can be identical to when it's level
00:19 defaultro the leadscrew is nice too but the design is yucky
00:19 Triffid_Hunter counterweight also doubles the rotational inertia which is probably a *good* thing for a camera dolly but may be problematic in other cases
00:19 defaultro it's also more expensive
00:19 defaultro yup
00:21 Triffid_Hunter defaultro: ps: http://www.aliexpress.com/item/NEMA17-78-Oz-in-CNC-stepper-motor-stepping-motor-1-8A/541709270.html match A4982 and friends perfectly
00:22 defaultro ok
00:23 defaultro what if using battery? looks like it's going to drain it really fast
00:24 evil_dan2wik defaultro, 6.8AH battery would give around 4-6 hours of run time
00:24 defaultro ok
00:24 evil_dan2wik I think.
00:24 defaultro that's really good
00:25 defaultro holding torque is even 52 which is nice
00:25 defaultro that can do 17lbs at 0rpm
00:25 Triffid_Hunter defaultro: it's the winding resistance and rated current which you want to keep an eye on.. lower resistance is better, zero would be ideal
00:26 defaultro can you please check the one I bought. Tell me if it's bad
00:26 GargantuaSauce_ i'd sure like to have some cheap superconducting motors
00:26 defaultro http://www.stepperonline.com/nema-17-bipolar-stepper-12v-04a-40ncm567ozin-17hs150404s-p-14.html
00:26 defaultro that's the one I bought few hours ago
00:26 defaultro 12v, 0.4A, 40Ncm
00:27 Triffid_Hunter defaultro: it'll be ok as long as you feed your A4982 15v or more, and you don't try to run it fast
00:27 defaultro got it
00:27 evil_dan2wik Triffid_Hunter, Have you seen his project?
00:28 defaultro :)
00:28 Triffid_Hunter evil_dan2wik: seen? no, don't think he's posted pics. I know he's moving a camera of some sort, that's about it
00:28 defaultro I posted the video previously
00:28 evil_dan2wik Triffid_Hunter, He showed me a video
00:28 Triffid_Hunter ah I missed it
00:29 defaultro let me pull it
00:29 defaultro Here is one I made with it, http://www.youtube.com/watch?v=c7Y93hxZdes
00:30 evil_dan2wik https://www.youtube.com/watch?v=A95uCHp5Q7Q
00:30 defaultro yup
00:30 defaultro you'll see the stepper motor(taken from dot matrix printer) there
00:31 defaultro 38mmx38mm motor
00:38 defaultro alright folks, I'm taking off. Catch you all later
00:40 GargantuaSauce_ sure am having a hard time finding the right balance of encouragement and "for the love of god learn the theory" with that dude
00:41 GargantuaSauce_ i mean to be honest it's pretty impressive that he's gotten this far while still having questions like "which pin on a transistor is the output"
00:42 Triffid_Hunter yeah there's only so much I can take.. when I start eating my beard I up and leave
01:02 evil_dan2wik He needs to google more.
01:03 GargantuaSauce_ yeah
01:49 MrCurious wow
01:50 MrCurious hats off to him for synergizing all the help he is given into something useful
01:50 Triffid_Hunter MrCurious: yeah that's why I keep coming back
01:51 MrCurious wife just told me its time to go to bed or to know regrets...
11:17 GuShH local grubmint fucks up again, lack of an htaccess allowed anyone to obtain anyone's picture and ID number http://bucket1.clanacion.com.ar/anexos/fotos/36/privacidad-en-la-era-digital-1793436.jpg
12:35 GuShH http://www.youtube.com/watch?v=svFwsJsHHGs
14:57 GargantuaSauce_ defaultro http://xn--d-bga.su/TAOE.pdf forgot about this
14:58 defaultro what is it?
14:58 GargantuaSauce_ a most sacred text
14:59 defaultro oh cool!!!
14:59 defaultro :D
14:59 defaultro Thank you so much!!!!! :)
21:46 defaultro I think i need to find a new job
21:51 Tom_itx i agree
21:53 InSaneGame second
22:02 defaultro :)
22:03 defaultro got pissed off this evening when I read the comment of my boss to the hack I found on our application. He declined the fixes I did! What a friggin boss
23:26 GuShH defaultro: write a backdoor in the meantime
23:26 defaultro hehehe :D
23:27 ShH can't s
23:27 defaultro me too, my head is aching because I've been thinking about it
23:27 defaultro i'm really pissed off
23:28 defaultro then in the evening, he posted to the whole group in our chat channel
23:28 defaultro he acknowledges it
23:28 defaultro but he declined my fixes
23:28 defaultro "It seems Neil is able to perform JS injection from the UI. I tried the same trick using only the API and I got this"
23:28 GuShH I'm pissed off at this supplier I found for aluminum, brass, etc... he sent me a quote 40% higher than it should be, he's just reselling the stuff to me (trying to at least) asshole
23:29 defaultro wow
23:29 defaultro some are like that, they trick us
23:29 GuShH only problem with the regular supplier is the distance, getting the stuff from point A to point B costs a few bucks
23:29 defaultro k
23:29 GuShH yeah I thought he would just tell me the name of his supplier, since he deals with extrusions not rods, etc.
23:29 defaultro yup
23:30 GuShH instead he wants to take a piece of the pie.
23:30 ShH shakes
23:30 GuShH otoh I would still make a profit if I bought from him, alas a smaller profit...
23:30 ShH wonders if all jews are the
23:31 defaultro wow
23:31 GuShH it's true what they say though
23:31 GuShH I've dealt with several jews so far they're all the same.
23:31 GuShH But I'm sure there are a few exceptions?
23:31 GuShH Also just an assumption based on his last name, and to somehow get back at him... also because I'm bored.
23:32 GargantuaSauce_ casual antisemitism is the best
23:32 GuShH "'cos I was bored..." - Hitler
23:33 GuShH GargantuaSauce_: not as good as casual sex though
23:33 GargantuaSauce_ this is true
23:33 GuShH So there have been untrue things said by me?
23:33 GuShH NAME A FEW
23:33 GargantuaSauce_ i would consider it the default state
23:34 ShH bl
23:34 rgantuaSauce_ lowers the flashl
23:36 GargantuaSauce_ i hope you've found this conversation....illuminating
23:37 ShH fr
23:37 GuShH Illuminating will be the outcome of what I've been coding for a month
23:37 GuShH It could however get me 6 feet under in theory
23:37 GuShH I BET YOU WANT ME TO RELEASE IT NOW
23:38 GargantuaSauce_ I wouldn't mind knowing wtf it is
23:39 GuShH It's a service that generates price lists from every major vendor in my country, provides said lists for free to the public and also generates several plots / graphs of actual inflation in real time, based on said lists. This, does not exist here. And the GRUBMINT does not want it to exist, because they're all about denying inflation.
23:41 GuShH Two major goals, one is to have a law grafted (at least) with regard to price lists (forcing all major companies to provide one free of charge if a customer requests one, currently nobody does this so they can charge you whatever they feel in most places)
23:41 GuShH the second one is to reveal actual inflation values, which are currently obscured.
23:42 GuShH And the hidden agenda is for everyone who feels like it to either copy the service or utilize the lists to generate their own databases and analysis tools.
23:43 GuShH I'm just sick of this game, people here are goldfish in general... or sheep, whatever you like. They don't quite notice when prices go up.
23:44 ShH notices that's also why he can't quite sleep, he has to finish
23:45 GuShH So far a months worth of data reveals that some items have gone up by up to 150%, some by 100% ("late adjustments" I call these) and in general I projected a 10% to 15% monthly inflation rate, whereas the GRUBMINT claims it's 10% annually...
23:47 GuShH The data is there, it's public data, whether running the code to obtain the data is legal or not, I would argue it is... as it mimics a regular user client at a similar browsing speed as to not raise any flags (total transfer speed is not important for this application, nor is multi-threading as the data does not change at a fast rate)
23:48 GuShH And anyway this is what search engine spiders do, why should it not be legal as far as there's an obscured link to an "erase me" form...
23:48 GargantuaSauce_ destructive GETs are the best
23:48 Triffid_Hunter GuShH: yeah have a process whereby individual listings can be removed by filling out a 37 page form and faxing it in
23:49 Triffid_Hunter GuShH: to a $1 per minute number forwarded to a fax -> email(pdf) service
23:49 GuShH GargantuaSauce_: it's not destructive in any way... it cannot possibly even begin to DoS any of the servers
23:49 GuShH every loop is delayed on purpose.
23:49 GuShH at random intervals plus a minimum rate.
23:49 GuShH Triffid_Hunter: hahah
23:49 Triffid_Hunter wget is good like that ;)
23:49 GargantuaSauce_ no I mean poorly written webservices that use GETs to carry out actions like deletion
23:49 GuShH But how the data is obtained... seems irrelevant
23:50 GargantuaSauce_ it does sound like something that will get you...scrutinized
23:50 GuShH I don't even have to run the scripts on a server, I can use any box... anywhere...
23:50 GuShH GargantuaSauce_: I know, at least.
23:50 GuShH People have gone missing for far less.
23:51 GargantuaSauce_ that's a pretty fantastic way to express one's "civil displeasure" in any case
23:51 GargantuaSauce_ most people just go out and break things!
23:51 GuShH Here's the thing, I can also display special deals based on the same analysis... The entire purpose of the service is not to be destructive.
23:52 GuShH Also I'm sick of not being able to have price lists, so I'm generating them myself.
23:52 GuShH And it's true I do exploit a few vulnerabilities on some sites, specially those running IBM e-commerce packages that are often very poorly implemented
23:52 GuShH and allow you to use their crappy ajax implementations against them by fetching 100s of items at once
23:53 GuShH so far every asp.net commerce site uses one form or another of lousy encryption and encoding
23:53 GuShH seems like an obfuscated base64... that's as much as I know right now, never dealt with .net products
23:54 GuShH of course if the js client can resolve the data, so can I.