#robotics Logs

Jan 31 2013

00:28 MrTrick (from this angle, it looks like it's used for the shoulder extension and the bicep)
00:30 MrTrick I would have thought a linear stepper motor would do a better job.. (and in the video, you've got to feel sorry for those poor servos!)
00:32 rue_house pitch is a bit low
00:32 rue_house but that looks reasonable
00:33 rue_house is that an arduino?
00:33 rue_house oh wow, that thing is big
00:33 rue_house those aren't standard servos, their too big
00:33 rue_house all 3d printed, well done
00:34 MrTrick see Tom L's link in the scrollback.
00:34 rue_house thats got to be almost $200 in plastic right there
00:35 Jak_o_Shadows1 the future!
00:35 rue_house ah, they used a painting robot image as a backdrop
00:36 MrTrick hmm, surely something like http://www.ebay.com.au/itm/New-Nema-17-1-7A-150mm-Stepper-Motor-Linear-Actuator-w-Brass-Nut-Hobby-CNC-/330860168186
00:36 rue_house I feel for the bearings on those servos
00:37 rue_house I need ot try to make some acme thread with my lathe
00:37 MrTrick lets see... doesn't say how much linear holding force it has... but at 8mm per revolution, a 1.8 deg stepper at 25K steps can do 1metre/s top speed. o_O that sounds overly high.
00:38 rue_house so does 25k steps
00:39 MrTrick Really? I thought that was kind-of standard?
00:39 rue_house maybe for microsteps
00:41 MrTrick Hmm, grbl on an atmega328 can do up 30kHz pulserate.
00:42 rue_house yes, that dosn't mean there is a motor made that can take that full step rate
00:42 MrTrick The driver chip they use claims up to 500khz O_O http://www.ti.com/lit/ds/symlink/drv8818.pdf
00:42 rue_house those pulses go to microsteppers that divide it down by 8 or 16
00:42 MrTrick ah, I knew there had to be a bottleneck somewhere. ^_^ The motor's internal inductance?
01:32 FreezingCold What exactly does a V-belt of 3V-480 mean?
01:33 rue_house belt?
01:33 rue_house is it a synchro belt?
01:33 rue_house 'do not bend' ?
01:34 RifRaf hi rue\
01:34 rue_house hey rif
01:35 RifRaf workin of rev3 of gripper for arm
01:35 rue_house hows it going togethor? did you find your missing peies?
01:36 RifRaf it works, but making it smaller
01:36 RifRaf 26grams including servo
01:36 RifRaf but want about 20
01:37 RifRaf 2 grams over
01:37 RifRaf 22 grams and 11 is the servo
01:38 rue_house did you not see my balanced arm?
01:38 FreezingCold Never mind
01:38 RifRaf got some new short brackets to join sg90 servos easy as well
01:38 FreezingCold Figuerd it out
01:38 RifRaf not that i remember
01:38 rue_house oh well
01:38 rue_house check this out
01:38 rue_house !assist robots
01:38 tobbor Possibly http://eds.dyndns.org/~ircjunk/robots
01:39 rue_house http://eds.dyndns.org/~ircjunk/robots/arm4/p1010986.jpg
01:39 rue_house its a standing mobile
01:39 rue_house if you disconnect the motors is prettymuch stays put
01:39 RifRaf yep nice, was gonna make that design but for now will make a hanging arm
01:40 RifRaf less gravity to fight, these servos are weak, gonna get some metal gear ones
03:43 Tom_garage !thislog
03:43 tobbor This one: http://rueshouse.dyndns.org:82/~ircjunk/irclogs/html/%23robotics-2013-01-31.html
05:32 orlok woo
05:32 orlok :D
07:10 orlok COLD.
07:10 orlok i think its like, 10 degrees or something
07:31 Tom_itx 25f here
08:26 NightRavenXS has anyone of you guys disassembled a TV remote?
08:26 dunz0r A few times, yes.
08:26 NightRavenXS dunz0r, have you seen a microcontroller inside?
08:27 dunz0r NightRavenXS: In a fairly old one I did. The other ones have had one of those asics.
08:27 dunz0r epoxy-lumps
08:27 NightRavenXS what is that?>
08:27 NightRavenXS an alternative for MCUs or a way to hide them?
08:28 dunz0r NightRavenXS: http://en.wikipedia.org/wiki/Application-specific_integrated_circuit
08:29 NightRavenXS ahh
08:29 NightRavenXS thanks dunz0r
08:29 NightRavenXS i didnt know about these
08:31 NightRavenXS because i opened a few calculators , a TV remote and RC plane controller, and i didnt see an MCU
08:31 NightRavenXS only something like a big black dot
08:35 dunz0r NightRavenXS: Yeah. They're called chip-on-board. It's a bare chip, to save money on packaging
08:35 dunz0r NightRavenXS: http://www.pcmag.com/encyclopedia_term/0,1237,t=chip+on+board&i=39643,00.asp
08:36 NightRavenXS thanks for enlightening me :)
14:22 RifRaf 4dof+gripper
15:43 ZinnSoldat am i the only one here?
15:43 DagoRed right now yes
15:45 ZinnSoldat pretty bad..
15:52 DagoRed why?
15:52 DagoRed why is that bad?
15:52 DagoRed The disclaimer "STAY AROUND TO GET AN ANSWER! TIMEZONES YA KNOW!" was put up for a reason.
15:56 ZinnSoldat because
15:56 ZinnSoldat i did read it that's why i asked ;)
16:00 DagoRed heh.
16:00 DagoRed Well... I'm at work so technically I shouldn't be on IRC.
16:09 ZinnSoldat then why are you here? go working!
19:08 RifRaf !thislog
19:08 tobbor This one: http://rueshouse.dyndns.org:82/~ircjunk/irclogs/html/%23robotics-2013-02-01.html
20:09 FreezingCold Anybody ever heard of this? http://www.firstroboticscanada.org/main/frc/
20:10 Jak_o_Shadows I've heard of first robotic competition
20:14 FreezingCold I'm invited to join a team, just wondering what's it about
20:15 Jak_o_Shadows Not quite sure. It's a north american thing i think.
20:18 FreezingCold Yeah, I'm in Canada (lol you should be able to tell from the link...)
20:18 Jak_o_Shadows yeah.
20:28 FreezingCold The thing is that it's at a high school... I think I'd feel a bit weird hanging around
20:29 Jak_o_Shadows Shave.
20:34 rue_house I wrote all these wonderfull fucntions,
20:34 rue_house and I realized I can replace them all with macros
20:35 ace4016 gross
21:17 e_shop3 expl
21:21 e_shop2 expl