#robotics Logs

Dec 23 2012

#robotics Calendar


02:34 rue_mohr robots are best when they are entertaining
02:34 rue_mohr ( http://www.youtube.com/watch?feature=player_embedded&v=Djc8FPHs45o )
02:41 Jak_o_Shadows rue_mohr: I have an electric fly swatter sitting here open on my desk, and i'm trying to decide waht to do with it
12:28 rue_mohr ok I have to make a table for a lathe
13:01 Tom_itx rue_mohr, did they send you dimensions finally?
13:03 rue_mohr no I recieved the lathe
13:03 rue_mohr its 31.5" between the bolts
13:03 Tom_itx just in time for christmas
13:03 rue_mohr :)
13:03 rue_mohr now I have to get the table assebled
13:03 rue_mohr need to re-liberate the welding tent
13:05 Tom_itx this should be a professional job
13:05 rue_mohr hmm need some #10 wire for the truck
13:05 Tom_itx you've had plenty of practice by now
13:05 Tom_itx i got some #6
13:05 Tom_itx 8
13:05 rue_mohr suppose I should get started, its miserable out
13:05 Tom_itx fine strand
13:06 rue_mohr yea, I need tranded
13:06 Tom_itx yeah it's cold here as well
13:06 rue_mohr 40A line to the back for power sockets
13:06 rue_mohr but I can do that anytime
13:06 Tom_itx got my blue lcds working last night
13:06 Tom_itx it was for an amp
13:06 Tom_itx i pulled out of the truck
13:06 rue_mohr cool
13:07 Tom_itx 2 lines run, one for each amp
13:07 Tom_itx not it just sits in a box
13:07 Tom_itx now
13:07 rue_mohr I have a portable winch I want to be able to plug in back there
13:08 rue_mohr and there is no point in not using it for the lights in the canpoy when its on
13:08 Tom_itx how many amps does the lathe require?
13:08 rue_mohr right now I have one of theose 2 prong rubber things
13:08 rue_mohr 12A 120V
13:08 Tom_itx have you fired it up yet?
13:08 rue_mohr the shop has lots of circuits :)
13:08 rue_mohr yes
13:08 rue_mohr I faced a peice of plastic
13:08 rue_mohr couldn't help myself :)
13:09 Tom_itx got lots of tooling for it?
13:09 rue_mohr just enough
13:09 Tom_itx you can never have enough
13:09 rue_mohr knurling, right hand, stright, left hand, and parting
13:09 rue_mohr the parting holder is on backorder
13:09 Tom_itx plenty of tool steel for grinding tools?
13:09 rue_mohr yes
13:09 Tom_itx what size square does it take?
13:09 rue_mohr the carbide?
13:10 rue_mohr or the parting?
13:10 Tom_itx just tool steel for grinding special bits
13:10 Tom_itx i get square blanks
13:10 rue_mohr I have 1/4" and 3/8
13:10 Tom_itx got some carbide as well
13:10 rue_mohr hss
13:10 Tom_itx that or cobalt
13:11 Tom_itx not alot of difference
13:11 rue_mohr I was trying to think of someting to make
13:11 Tom_itx hot end
13:11 rue_mohr heh
13:11 rue_mohr have one
13:11 rue_mohr better than stainless, quartz
13:12 Tom_itx you got 3 and 4 jaw chucks?
13:13 rue_mohr yes, and a plate
13:13 Tom_itx i've never used my plate
13:13 rue_mohr :)
13:13 rue_mohr it dodn't come with a dog for it
13:14 Tom_itx i got one of those too but never use it
13:14 rue_mohr machinist tricks I dont know
13:16 rue_mohr I need to go get a tree
13:16 rue_mohr later
14:15 home rue_mohr: lol
14:16 home rue_mohr: stupid rc car didnt work
14:21 dryc-x Hi there :-)
14:22 dryc-x Any one here?
14:27 KimLaroux I've been on IRC for a decade, and people's impatience never fails to impress me
14:28 KimLaroux He stayed 3 minutes... I wonder if he gets faster response on social networks
14:51 exiff γŸγΆγ‚“
14:53 DagoRed KimLaroux: same
14:54 KimLaroux I can see him pulling in a drive trough: place command, look at watch, leave if a minute as past
14:54 KimLaroux has*
14:59 DagoRed As long as he pays first.
15:00 KimLaroux you usually pay after getter served, but he probably leaves before
15:04 DagoRed not in America
15:04 DagoRed We pay first... then wait... and wait....
15:05 DagoRed The US is retarded. We're screwed.
15:07 exiff wherever dryc-x is, i bet he doesnt realise he started an hour long conversation.
15:22 rue_mohr home, how "didn't work"
15:23 rue_mohr well the top frame of the lathe table is finished
15:23 rue_mohr its 1/2" out of square, and about 1/16" of twist
15:24 rue_mohr I think the 400lb lathe with fix the twist
15:30 home rue_bed: as in, the RC car did not work with the RC
15:30 home so now I have 2 motors
15:30 home 6 AA bateries, 4 of em NiCAD
15:30 home and urgh
15:38 rue_mohr hu?
15:38 rue_mohr you got an rc car that didn't work?
15:42 rue_mohr !thislog
15:42 tobbor This one: http://rueshouse.dyndns.org:82/~ircjunk/irclogs/html/%23robotics-2012-12-23.html
15:42 rue_mohr http://rueshouse.dyndns.org:82/~ircjunk/irclogs/html/%23robotics-2012-12-21.html
15:42 rue_mohr oops
15:43 rue_mohr fixed
15:43 Tom_itx what was broke?
15:43 rue_mohr the router didn't have the log server mounted
15:44 Tom_itx channels keep telling me not to log
15:44 Tom_itx i'm beginning to tire of irc
15:44 rue_mohr aren't you glad we control these ones?
15:45 rue_mohr if they ask you not to log ask them not to make an ass of themselvs so often
15:45 Tom_itx i didn't have to comply but i did
15:45 Tom_itx they didn't want the log to reflect bad comments made of their employers
15:45 rue_mohr if its someone elses channel then fiar enough
15:45 rue_mohr I log so that the same questions dont go around and aorund and around
15:45 Tom_itx i may suggest to not say them to begin with
15:46 rue_mohr yea
15:46 Tom_itx picture a nice heavy duty climbing rope
15:46 Tom_itx with a couple strands left holding it in one piece
15:46 rue_mohr nope, my mind is fixed on a steel table
15:46 rue_mohr Tom_itx, stick around, your not obligated to do anyhting
15:47 dryc-x Hello:-)
15:47 rue_mohr dryc-x, are you the 30 seconds guy?
15:47 rue_mohr you are
15:47 rue_mohr bye!
15:47 dryc-x What do mean?
15:47 Tom_itx you must leave too quick
15:47 rue_mohr aska question and leave 30 seconds later
15:47 rue_mohr dryc-x,
15:47 rue_mohr !thislog
15:47 tobbor This one: http://rueshouse.dyndns.org:82/~ircjunk/irclogs/html/%23robotics-2012-12-23.html
15:47 dryc-x I just joined here..
15:48 rue_mohr ^^^ see what people said
15:48 dryc-x It was internet problem! Sorry
15:48 rue_mohr uhuh
15:49 dryc-x I'm having a problem regarding h-bridges..
15:49 rue_mohr Tom_itx, besides, if anyone asks, I'm happy to remove a clip from a log fle
15:49 Tom_itx why are they called H bridges?
15:49 Tom_itx not if you don't log the channel
15:49 dryc-x They represent an H shape in their design
15:50 Tom_itx i may just rename the bot and join it back anyway
15:50 Tom_itx maybe i'll call this one 'snoopy'
15:51 dryc-x I'm using 2n2222 transistors but I always get a dysfunctional circuit!
15:51 rue_mohr http://eds.dyndns.org/~ircjunk/tutorials/elex/pwm/pwm.html
15:51 Tom_itx show me your table design
15:51 rue_mohr dryc-x, how big are your motors?
15:51 rue_mohr Tom_itx, 2 mins
15:52 dryc-x So far they are small for experiments..
15:52 dryc-x Oh by the way, if I use larger car-wipers motor, what transistor should I use? Or should I use relays??
15:53 Tom_itx bigger ones
15:53 Tom_itx mosfets
15:53 dryc-x I have a serious problem that might be hard to explain!
15:54 dryc-x I can't simply get whatever I need even if I've got the money for!
15:54 Tom_itx we handle serious problems before breakfast
15:54 rue_mohr dryc-x, how big are the mtoors your trying to run with the pn2222
15:54 Tom_itx rue_mohr, wiper motors
15:54 dryc-x Because not everything is available here in Iraq!
15:55 dryc-x So I have to use some parts that are commonly used for other purposes
15:55 rue_mohr dryc-x, 2n2222 cant operate wiper motors
15:56 rue_mohr they might be able to operate motors about 4cm^3 or smaller
15:56 dryc-x I chose wiper motors because they are available in car maintenance centers
15:56 Tom_itx maybe i should solder something
15:56 Tom_itx it may cheer me up a bit
15:56 rue_mohr Tom_itx, I'm slated to make a clock later
15:56 rue_mohr do you have a 32.768khz crystal?
15:56 Tom_itx i have a bunch of those
15:56 dryc-x So I always have to look for alternatives
15:57 rue_mohr ever hooked one up to the second clock of a mega32?
15:57 Tom_itx no but i have one on a 128
15:57 rue_mohr dryc-x, do you have access to old computer parts?
15:57 dryc-x I'm sorry if I got far off topic, but I'm feeling lonely here regarding my robotics hobby :(
15:57 rue_mohr dryc-x, how long have you been building things?
15:57 dryc-x Yes, I'm collecting old computers for such purposes
15:58 rue_mohr each power supply has 2 transistors in it that are good to 4A
15:58 rue_mohr dryc-x, 2n2222 are ok for up to 0.5A
15:58 rue_mohr dryc-x, do you have a multimeter?
15:58 dryc-x Yes I do :)
15:59 rue_mohr how much current does your motor pull if you hook it right up?
15:59 dryc-x I don't know how to measure it! Should i connect it in series?
16:00 Tom_itx http://tom-itx.dyndns.org:81/~webpage/misc_stuff/mega128.jpg
16:00 Tom_itx member pepsi's board?
16:00 rue_mohr tom have you never hooked up a 32768?
16:00 rue_mohr dryc-x, do you have a webcam you can take pics with?
16:00 Tom_itx what is that?
16:00 rue_mohr khz
16:00 Tom_itx i have
16:00 Tom_itx why?
16:01 Tom_itx use no caps
16:01 Tom_itx they're internal
16:01 dryc-x I have a cam, yes.. But I can't take pictures now
16:01 rue_mohr if you hook up the 32768khz crystal to the secondary osc you can make a rtc
16:02 Tom_itx i'm aware of that
16:02 dryc-x I believe the wipers motor should drain quite a lot of current
16:02 Tom_itx generally clocks timer2?
16:02 Tom_itx i suppose it varies from chip to chip
16:02 rue_mohr I think so
16:02 rue_mohr want to look at some m32 code that uses it?
16:03 Tom_itx does m32 let you use a 32khz xtal that way?
16:03 dryc-x Can relays function just as h-bridges??
16:03 Tom_itx i never botherd looking
16:03 Tom_itx not that well
16:03 rue_mohr yes
16:04 rue_mohr you set up the dividers and get an overflow every second
16:04 dryc-x I once designed and built a 6v relay circuit to control 2 motors, it worked but was sluggish and slow to response.. Can that be improved??
16:05 rue_mohr yo ucan make a hybrid, F/R with a relay and on/off with transistor
16:05 Tom_itx what am i to do with this said code?
16:05 rue_mohr I thought you might be interested in using a crystal and stuff to make a 1hz flasher
16:06 rue_mohr then I can get the code back and finish a clock with it
16:06 rue_mohr (binary clock)
16:06 dryc-x Nice idea! Thanks :) will that decrease response time?
16:06 rue_mohr I have the code for breaking out ethe seconds/mins/hours
16:06 rue_mohr dryc-x, for on/off
16:06 rue_mohr !assist projects/lathe
16:06 tobbor Possibly http://eds.dyndns.org/~ircjunk/projects/lathe
16:06 Tom_itx i did a dallas rtc once
16:07 dryc-x And any transistor meeting the voltage/current rating can work??
16:07 rue_mohr http://eds.dyndns.org/~ircjunk/projects/lathe/p1040769.jpg <-- the point on the centre is REALLY sharp
16:07 rue_mohr dryc-x, if operated properly
16:08 rue_mohr dryc-x, what do you know about transistors
16:08 Tom_itx 0770 needs an extra nut on it
16:08 Tom_itx to lock it
16:08 rue_mohr http://eds.dyndns.org/~ircjunk/projects/lathe/p1040771.jpg
16:08 rue_mohr oh, I was gonna use a grub screw
16:08 Tom_itx is that frame heavy enough?
16:08 Tom_itx don't use a grub screw
16:08 Tom_itx gawd must you use them on EVERYTHING!!
16:09 rue_mohr the legs are gonna be moved udner the cross bars that hold the lathe
16:09 rue_mohr :)
16:09 dryc-x I know they have 3 connections: collector, emitter, base.. And base is just like the trigger to allow flow from collector to emittor
16:09 rue_mohr dryc-x, let me teach you all about them
16:09 Tom_itx gate sourc drain
16:10 rue_mohr http://eds.dyndns.org/~ircjunk/tutorials/elex/qwhathow.html <--- dryc-x read this
16:10 dryc-x I'll be glad to, rue_mohr :-)
16:11 Tom_itx what's the blue tubing / cable in 0772?
16:11 rue_mohr air line
16:12 Tom_itx how heavy is the lathe?
16:12 Tom_itx .062 wall tubing?
16:18 dryc-x Nice link, I didn't finish it yet but I have a question: is it required to know motor current in order to calculate the base resistor?
16:20 dryc-x Apparently 'yes' for my own question! Now the problem is how to measure motor current??
16:27 dryc-x Pardon me but do I need to repeat my question to be seen? Or it remains visible?
16:27 ace4016 ?
16:27 Jak_o_Shadows nope dryc-x, not unless somebody you want to see it has logged in in the mean time
16:28 dryc-x Ok, so how do I measure motor current :D
16:28 ace4016 dryc-x, the nature of IRC is instantaneousness, which includes people's attention (i.e. one second they're here, the next they're gone)
16:28 ace4016 also, for your answer, a hall effect sensor might help
16:28 ace4016 wait...
16:28 dryc-x What is that?!
16:29 dryc-x Can I measure it with a multi meter??
16:29 Jak_o_Shadows Depends, but make sure it's not above your DMMs limit
16:30 ace4016 sure; were you looking for measurements in a lab environment? or continously for your robot or whatever you're making?
16:30 dryc-x How do I do it? I mean where the multi meter should be connected to the DC motor??
16:31 ace4016 it should be connected in line to the motor
16:31 dryc-x I need it for my robot to determine the value of resistor used for transistor..
16:31 Jak_o_Shadows current is constant in series.
16:31 ace4016 o.0?
16:31 ace4016 that doesn't sound right :P
16:32 dryc-x Should I put the multimeter in serious with the motor?
16:32 dryc-x *series
16:32 ace4016 you can usually determine the current needed in other ways, and the transistor's biasing shouldn't be affected by what is connected to it
16:32 ace4016 if you're trying to measure current with a DMM, yes
16:32 Jak_o_Shadows dryc-x: Yes, but if you're using a beefy motor, make sure that if it draws over 10amps (usually), you don't leave it connected
16:33 dryc-x How do I choose resistor for the base of a transistor?
16:34 ace4016 the motor does not determine that
16:34 ace4016 the specs of the transistor does
16:35 ace4016 typically you want to voltage between base and emitter to be .65V (assuming NPN)
16:35 Triffid_Hunter dryc-x: measure resistance of motor. use ohm's law to calculate current. multiply current by 4. divide by worst-case hFe, and use ohm's again to find resistor that gives suitable base current
16:35 ace4016 depending on your power source, you can determine what resistor is needed
16:35 Triffid_Hunter dryc-x: at this point, if the motor isn't tiny, you'll realise that mosfets are a really great idea
16:35 ace4016 hehe
16:36 Triffid_Hunter because driving 2A into a transistor's base requires another stage of drivers
16:36 Triffid_Hunter whereas you can get an IRLB8743 and hook it directly to your microcontroller
16:36 Triffid_Hunter and it will carry 15A
16:37 dryc-x Can these mosfets be found in old computer power supplies??
16:37 ace4016 o.0
16:37 ace4016 most likely
16:37 Triffid_Hunter dryc-x: on the motherboard near the CPU there's generally a few decent ones in D2PAK
16:37 ace4016 power mosfets
16:37 Triffid_Hunter dryc-x: the ones in the power supply are generally high voltage low current and are thus useless for robot motor driving
16:38 rue_mohr Tom_itx, 400lbs
16:38 dryc-x What home appliances can contain useful transistors?
16:38 rue_mohr 1/8" tube
16:38 Triffid_Hunter dryc-x: you may be interested in https://github.com/triffid/ESC which I constructed recently, and proceeded to strip all the gears in my R/C's gearbox by doing donuts and powerslides in high gear
16:39 Triffid_Hunter dryc-x: useful power mosfets for medium current low voltage applications? computer motherboards near the cpu is about it
16:39 dryc-x Helpful for 12v motor wipers for example?
16:39 Triffid_Hunter dryc-x: IRLB8743 are in the ballpark of $1/ea from various online vendors
16:40 dryc-x *wiper motors
16:40 Triffid_Hunter dryc-x: yes it's for brushed DC motors, haven't designed my BLDC one yet
16:40 dryc-x Unfortunately I can't order online from here in Iraq, too complicated to do so..
16:42 Triffid_Hunter dryc-x: iraq eh? have the americans stopped shooting everyone yet?
16:43 dryc-x Fortunately they did! After our Iraqi government insisted on US to pull the troops..
16:44 Triffid_Hunter oh neat
16:45 dryc-x US = USA not us ;)
16:45 Triffid_Hunter yeah I figured that, didn't hear about a 51st state being added in the middle east
16:46 dryc-x hhhh :-) No, we are an independent country with an elected government..
16:47 rue_mohr which some asshole has manipulated himself into
16:47 dryc-x Who?
16:48 Triffid_Hunter rue_mohr: yeah of course, national elections run on the same sociological principles as the high school popularity contest, merit is not involved
16:49 dryc-x Still better than a dictatorship, though!
16:50 dryc-x I mean here we have far more choices than just 2!!
16:54 rue_mohr maybe I'll clear my head if I do my grocery shopping
17:01 dryc-x sorry I was disconnected due to internet problem.. Did I miss anything?
17:01 rue_mohr !thislog
17:01 tobbor This one: http://rueshouse.dyndns.org:82/~ircjunk/irclogs/html/%23robotics-2012-12-23.html
17:02 dryc-x Nice, thanks :)
17:06 dryc-x Wow! I didn't expect that I caused so much annoyance when I first tried to join this channel! (O_o)
17:08 yc-x changed nick na
17:09 yc-x actually did
17:10 Triffid_Hunter dryc-x: http://letsmakerobots.com/files/userpics/u4631/Min_H-bro.jpg <-- R1 and R2 should probably be 100r or less. also if you turn both sides on at once it will catch fire
17:11 Jak_o_Shadows which may be desirable
17:11 dryc-x What are R5 and R6 for?
17:12 Triffid_Hunter dryc-x: to reduce leakage if the inputs are allowed to float
17:13 the-30-sec-guy ok, but are they essential?
17:15 dryc-x-30sec-guy Can I simply not put them in that circuit?
17:22 dryc-x-30sec-guy I feel my experience in mechanics is rather poor! How can I improve that?
17:22 dryc-x-30sec-guy I man robotic mechanics..
17:22 dryc-x-30sec-guy *mean! auto correct kills!
19:29 rue_mohr few more cross peices and I should be ok
19:29 rue_mohr this is by far the most crazy heavy duty table I'v ever made
19:30 Jak_o_Shadows There's no kill like overkill!
19:35 rue_mohr well its for a lathe
19:35 rue_mohr and I'm being told I'm underdoing it
19:37 KimLaroux from what I've seen, do are =P
19:37 KimLaroux you
19:38 KimLaroux If I were you, I would have made it from 4X4 or 2X6 steal tubes
19:38 KimLaroux or is it steel?
19:38 KimLaroux I always mix up these two
19:39 Jak_o_Shadows steel
20:29 Tom_itx it should be ok
20:30 Tom_itx i did inquire of the wall thickness
20:30 Tom_itx .062 or .090" ?
20:43 m_itx bets rue_mohr gets a 'farmer tan' from wel
22:24 rue_shop3 lathe 400lbs
22:24 rue_shop3 medical actuator capacity: 800lbs
22:44 Tom_itx progress?
22:45 rue_shop3 hmmm
22:45 rue_shop3 need to raise 400lbs 20" in a confined space
22:45 Tom_itx not so hard
22:46 Tom_itx seems like a short table
22:47 rue_shop3 not a huge lathe
22:48 Tom_itx what's the swing size?
22:48 rue_shop3 the egyptians were good at this, do we have any egyptians here today?
22:48 rue_shop3 its 10x22
22:48 Tom_itx i've moved heavy stuff before
22:48 Tom_itx 22 long?
22:48 Tom_itx seems short
22:48 rue_shop3 wide headstock
22:48 Tom_itx i spose mine is as short
22:49 rue_shop3 11" is head
22:49 rue_shop3 8" is tail
22:49 Tom_itx 11" chuck?
22:49 Tom_itx or swing
22:49 rue_shop3 5" is chuck
22:49 Tom_itx that's not so bad
22:49 rue_shop3 supposed to swing 10" dia
22:50 Tom_itx you got the bigger of the two then
22:50 rue_shop3 how do I pick it up 20"
22:50 rue_shop3 I'm thinking blocking
22:50 Tom_itx block it up end at a time with 2 x 4's
22:50 Tom_itx slowly raising it
22:50 Tom_itx don't let it get wobbly as you go up
22:51 rue_shop3 siding it over isn't a breeze either
22:51 Tom_itx that's where low friction material comes into play
22:51 Tom_itx we move a full size bridgeport with water pipe
22:52 rue_shop3 I think its top heavy
22:53 Tom_itx i'm sure it is
22:53 Tom_itx you don't have a hoist?
22:53 rue_shop3 I do, nothing to attach it to
22:53 Tom_itx i thought you made an A frame
22:53 Tom_itx set it near the door
22:53 Jak_o_Shadows Put your back into it
22:53 Tom_itx and mount it
22:53 Tom_itx then move it in as a single unit
22:54 Tom_itx make some temporary wheels for one end
22:55 Tom_itx remove the spindle and other stuff first to make it lighter
23:05 rue_shop3 Tom_itx, it cant fit in the shop
23:05 rue_shop3 I have the whole thing on a hospital bed whhelset, so I can wheel it around
23:06 rue_shop3 I just for some 4x4's under it, its 4" higher now
23:06 rue_shop3 (20 tonne jack)
23:08 Tom_itx you should be able to lift one end ehh?
23:08 rue_shop3 no
23:08 rue_shop3 well, the tail end
23:09 Tom_itx the final lift needs bars across it so you can brace them up and set the table under it free and clear
23:16 rue_shop3 oh I'm stupid
23:16 rue_shop3 the world ended
23:16 rue_shop3 this is all a simulation
23:17 rue_shop3 I just have to gotget its heavy and lift it
23:17 rue_shop3 O_o this isn't as easy as I thought
23:18 e_shop3 concentrates, "its made from styrof
23:18 Tom_itx leverage
23:19 Tom_itx safety ropes or chains
23:39 KimLaroux lol rue, I just love your thinking
23:39 KimLaroux you should join the Mythbusters