#robotics Logs

Apr 11 2012

13:06 home guys
13:06 home what can I salvage from a old printer?
13:07 home also where can I find some h-bridges >,<
13:08 furrywolf what kind of printer? an inkjet, the most you can expect is a couple crappy steppers, dc motors, and an optical encoder if you're lucky. a laser, larger motors, scanning mirror, etc.
13:09 home its an HP all purpose printer
13:09 home optical encoder, sounds very NICE
13:10 Skwint you can make an H bridge out of some resistors and 6 transistors
13:10 Skwint although there are even better options out there
13:10 home only have 2 transistors..
13:10 Skwint Do I remember you are hacking an RC car?
13:10 home Skwint: I dont want ot make an h-bridge
13:10 home Skwint: I dont have an rc car
13:10 home so L:/
13:10 home I have some drills, and printer lying around
13:11 Skwint ah, ok - I couldn't remember what you were doing as a project
13:11 Skwint I just took a floppy disk drive to bits and was very dissapointed at how boring the insides were
13:11 Skwint couple of dodgy motors
13:11 home explain?
13:11 home dodgy motors 0_0 ?
13:11 home I have a motor so far
13:11 home but not much of a way to control it XD
13:12 Skwint well, both motors give me the impression of drawing more current than I would like
13:12 home thats bad right XD
13:12 Skwint battery goes flat sooner :p
13:12 home blowign the fuses?
13:12 home oh I see L:/
13:12 home i need some way to control motors
13:12 Skwint so you want to control a motor ... forwards / backwards?
13:12 home are there motor controllers in the printer?
13:13 home Skwint: yes :D
13:13 Skwint there must be something in it like that, because it powers the ink gun up and down the guide
13:13 home will have to take a look when I have some time, hopefully in the weekeneds
13:14 Steffanx My weekend just started ):
13:14 Steffanx :)
13:14 Skwint look for a cluster of 4 transistors or 4 8 pin chips near where the motor is connected to the board
13:14 Skwint that's probably an H bridge
13:17 Skwint home: have you considered something like this: http://www.oomlout.co.uk/index.php?main_page=product_info&products_id=215
13:17 home maybe, mshould have bought some.. ;op;
13:17 home lol
13:18 Skwint for �3.50 you can't go too wrong, surely? :)
13:18 Skwint although the experts here will tell you what else you would need
13:18 Skwint I'm sure there's a reason most motor controllers cost a small fortune and that costs less than a hamburger and fries
13:20 Skwint looks like SN754410 is even better and half the price ... that worries me
13:20 Skwint it means I don't understand something :)
13:21 home lol
13:22 Skwint seriously, as far as I can tell, SN754410 will drive two motors forwards or backwards, with a maximum load of 1A
13:22 Skwint you don't know what current your motors draw do you?
13:24 home no, I do not
13:25 home oddly enouigh I cant find the motor
16:19 bsilvereagle Does anyone have recommendations for hollow bore (1/8" or so) shaft encoders? Preferably <$20 with a resolution of 16+ clicks or so. I'd prefer it to not have to play with the optics myself.
16:32 DanFrederiksen bsilvereagle, as I've said many times there is a huge deficit in available servo product
16:32 DanFrederiksen s
16:33 DanFrederiksen bsilvereagle, if nothing else maybe you can hack one from an old wheel mouse
16:33 ace4016 for hobbyist
16:34 DanFrederiksen ace4016, for anyone really. it goes without saying that the price has to be reasonable. at unreasonable prices you can have anything
16:34 bsilvereagle Nice to see you here DanFrederiksen. My last resort is an optical wheel but the wheels we're provided won't play nicely with that.
16:34 DanFrederiksen bsilvereagle, thanks. do I know you from somewhere else?
16:34 bsilvereagle http://www.usdigital.com/products/encoders/incremental/rotary/kit/e4p
16:34 bsilvereagle I'd be fine with that if it was hollow
16:34 ace4016 i remember seeing a kit for shaft encorders somewhere...been a while since i've pulled those websites
16:35 bsilvereagle DanFrederiksen: ##engineering, diesel.
16:35 ace4016 what's diesel about? cars or anything diesel engined?
16:35 bsilvereagle this was a discussion about tractors.
16:36 bsilvereagle and trucks
16:36 DanFrederiksen k
16:36 ace4016 ah
16:36 bsilvereagle are there some keywords that I should use when searching for this stuff?
16:37 bsilvereagle I was really hoping McMaster Carr had something cheap and low resolution
16:37 DanFrederiksen motors should come with encoders already..
16:38 bsilvereagle *should*. The instructors really want us to use an optical solution for non-servos.
16:40 DanFrederiksen doesn't it become a servo the moment you put encoders on it?
16:40 bsilvereagle yeah, but we're given straight DCs without encoders so for their purposes they're not servos.
16:45 bsilvereagle oh, if anyone was curious about the IC question I had a few weeks ago, the solution was "ic -l lib\handyboard -p \\.\com8 download code.ic"
16:45 bsilvereagle But I really doubt anyone still uses IC
16:48 bsilvereagle http://www.sparkfun.com/products/10596
16:48 bsilvereagle I'm thinking that attached to the end of the shaft w/ a coupler.
16:52 DanFrederiksen bsilvereagle, that doesn't look like it's meant for high speed
16:52 DanFrederiksen but maybe
16:53 bsilvereagle Hmmm. I think at most we'll be doing 120 RPM
16:54 DanFrederiksen you think?
16:54 DanFrederiksen wheel motor?
16:54 bsilvereagle Haha yeah. Two wheel motors, then one (the hi-speed one) turning a lead screw.
16:54 bsilvereagle Homemade linear actuator
16:59 Skwint I salvaged that set up out of an old floppy drive
16:59 Skwint motor turns screw which moves read-head along a guide rail
17:00 bsilvereagle Are you getting 3"+ push?
17:01 Skwint no - 3.5" floppy needs the head to move only the radius
17:01 Skwint infact, only the size of the gap in the metal protector that slides off, so about 1"
17:01 Skwint I guess if I used a longer screw it could go as far as I wanted though
17:02 bsilvereagle I was thinking that too
17:05 bsilvereagle "Rotational Life (Cycles Min)" I can turn it at that many RPM or after 15K rotations it's busted?
17:06 bsilvereagle http://search.digikey.com/us/en/cat/sensors-transducers/encoders/1966131?k=encoder
17:08 Tom_itx that's not what you're looking for
17:08 bsilvereagle I'm thinking I can couple the end of the shaft to one.
17:08 Tom_itx it won't hold up
17:09 Tom_itx that's not what you're looking for
17:09 bsilvereagle http://search.digikey.com/us/en/products/EVQ-WKA001/P13381SCT-ND/822317
17:09 bsilvereagle Possibly that then get the shaft to interface with it?
17:11 Tom_itx nope
17:11 bsilvereagle Haha so the US Digital one?
17:11 bsilvereagle http://www.usdigital.com/products/encoders/incremental/rotary/kit/e4p
17:11 bsilvereagle It's what FIRST uses
17:11 Tom_itx something that has good bearings in it
17:12 rue_house arg, if I stop trying to breathe, I stop breathing
17:12 Tom_itx so don't stop
17:12 rue_house missed my ferry to the training course, thats gonna suck
17:12 bsilvereagle Tom_itx: do you have a seller/producer in mind?
17:13 Tom_itx if that us digital has bushings it may be ok
17:13 Tom_itx the others would wear out quickly
17:13 Tom_itx they're made to be hand turned
17:14 Tom_itx rue_house what training?
17:14 Tom_itx i thought you were pretty smart as it is
17:14 rue_house FA sprinkler systems
17:14 Tom_itx oh
17:14 Tom_itx but that's a plumber's job
17:14 Tom_itx not a sparkie
17:16 bsilvereagle ight. Alright, on the US Digital page changing the CPR doesn't change the price - makes little to no sense to me. Shouldn't a higher resolution encoder cost more?
17:16 Tom_itx not necessarily
17:20 bsilvereagle I'm lost, what's the difference between single-ended electrical and differential?
17:20 Tom_itx differential is balanced +-
17:20 rue_house in single ended, one wire is ground
17:20 rue_house in differential, the signals move in opposite directions at the same tim
17:21 bsilvereagle So for the handyboard I'd want single-ended
17:21 Tom_L http://www2.electronicproducts.com/Watch_Amazing_video_from_space_shuttle_launch-article-fajb_nasa_video_apr2012-html.aspx
19:13 bsilvereagle Why is this channel # instead of ## ? Do you own #robotics Tom_itx ?
19:13 ace4016 because #robotics is older than the ## requirement
19:13 ace4016 if there even is one on this server
19:14 bsilvereagle fair enough.
19:52 DanFrederiksen because the foolish policy of freenode is not even consistent
19:53 bsilvereagle they didn't force it's consistency did they? They just want older channels to comply and new ones have to.
19:53 bsilvereagle They don't want to tick off the internet ;)
19:53 DanFrederiksen what was a half way decent premise was embraced with vogonic zeal and now the one who started it is dead and only vogons remain to enforce the mindlessness forever
19:54 DanFrederiksen it wasn't just new channels. pressure was randomly put on older channels to change. #physics was even hijacked in the name of it. I was an op in #physics and banned in ##physics
19:55 bsilvereagle Maybe just really high traffic older channels?
19:55 home what happened?
19:57 bsilvereagle There was a new standard that you could only have #channel if you could prove you owned the channel name/topic. Otherwise it's supposed to be ##channel
19:57 bsilvereagle Or if ##channel is a general topic, like physics or math.
19:58 DanFrederiksen the premise was that if microsoft wanted #microsoft they could get it and other who wanted to talk about microsoft should create ##microsoft
19:58 DanFrederiksen the sentiment is fine but moronic to elevate it to absolute law. but so it was done
19:59 DanFrederiksen how many official channels actually exist here I don't know. probably not many
19:59 DanFrederiksen but every was made to suffer for it
19:59 DanFrederiksen and clients like irc do not list ## channels...
19:59 DanFrederiksen mirc
19:59 DanFrederiksen everyone*
19:59 bsilvereagle FOSS projects like to have their lone #
20:13 zhanx lost a brother tonight
20:14 zhanx ied attack
20:15 bsilvereagle I'm sorry to hear that.
20:15 zhanx bbl
22:05 bobwrit well, this is quiet
22:28 tsmeow-afk