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[00:53:02] <rue_shop3> is there no eagle packag in debian anymore?
[00:53:35] <orlock> hey rue
[00:53:37] <orlock> hows things
[01:00:35] <Triffid_Hunter> rue_shop3: only debian I have here is armhf, def. no eagle for that :P
[01:59:42] <rue_house> it ws under non-free
[07:48:01] <hitch> does anyone know a buying list for build a small robot with arduino and 3dprinter?
[07:55:53] <hitch> i want order parts from mouser.com but can't decide which ones to buy
[07:57:42] <SpeedEvil> most stuff won't come from mouser
[07:58:44] <SpeedEvil> First thing to decide is what is a small robot. Is it a CD sized thing which follows a line, or a 80 ton small bot, with 1m of RHA equivalent and an autocannon in the head.
[08:00:44] <hitch> i thought of something like
https://www.youtube.com/watch?v=4a9aTn8atQU
[08:01:19] <hitch> can you suggest a shop to buy from (which ships to germany)?
[08:05:50] <SpeedEvil> hobbyking will have useful stuff
[08:07:02] <SpeedEvil> As a general point, I would encourage basic woodworking, as well as being able to 3d print stuff.
[08:07:17] <SpeedEvil> you can puit together basic stuff lots faster
[08:20:53] <hitch> thanks, hobbyking really seems more overseeable to me, i will choose my parts now
[09:13:08] <rue_house> SpeedEvil, I'll go for the 80 ton
[09:13:54] <rue_house> oh god, what an awefull way to 3d model
[09:14:11] <rue_house> making things out of stacked extrusions is so much simpler and renders to much faster
[09:54:09] <mrdata> lego ftw
[09:55:18] <mrdata> http://images.mocpages.com/user_images/10024/12347108901_SPLASH.jpg
[11:24:10] <jhylands> deshipu, have you played with I2C much?
[11:28:47] <deshipu> jhylands: a bit, why?
[11:30:16] <jhylands> I'm having a weird issue with a TLV493D magnetic sensor
[11:30:40] <jhylands> Here's a forum post I did that explains the issue:
https://www.raspberrypi.org/forums/viewtopic.php?f=44&t=154855
[11:31:00] <jhylands> page 13 of the user manual describes the startup procedure:
http://www.infineon.com/dgdl/Infineon-TLV493D-A1B6_UM-UM-v01_02-EN.PDF?fileId=5546d462525dbac401530e81c9db058c
[11:37:16] <jhylands> argh
[11:37:19] <jhylands> just figured it out
[11:37:53] <jhylands> turns out I needed to send the initialization in a single array using write_block_data instead of 2 calls to write_byte
[11:49:52] <deshipu> I see
[11:50:01] <deshipu> sorry, at a conference now, building robots :)
[11:52:10] <veverak> cool!
[11:52:14] <veverak> deshipu: will be photos?
[14:35:42] <hitchDiddy> does anybody have experiences with cameras on arduino?
[15:59:47] <deshipu> hitchDiddy: yes, they suck
[16:00:07] <deshipu> veverak: there are some on twitter
[16:03:13] <deshipu> veverak: Check out Nicholas Tollervey (@ntoll):
https://twitter.com/ntoll
[16:05:16] <veverak> cool!
[16:05:19] <veverak> :)
[16:06:51] <deshipu> btw, I talked with a ROS guy yesterday
[16:07:02] <deshipu> he said ROS works on rpi
[16:07:11] <deshipu> (the first one)
[16:08:24] <veverak> yeah
[16:08:27] <veverak> it works
[16:08:29] <veverak> I know that
[16:08:31] <veverak> did that several tims
[16:08:38] <veverak> it's just that it's not exactly the way I want it
[16:08:49] <veverak> deshipu: you either use ubuntu OR have to recompile all by yourself
[16:09:17] <veverak> for now I wait until it starts to be real issue
[16:09:25] <veverak> either I will find raspbian compatible repo or make one
[16:09:28] <veverak> :)
[17:03:38] <anonnumberanon> Need to learn everything about designing and manufacturing a DC motor.
[17:04:24] <Snert_> come onnnn... I bet McGuyver can do it lol :)
[17:04:47] <Snert_> with 3 toothpicks, and a piece of string
[17:05:14] <anonnumberanon> Heh of course.
[17:05:27] <Snert_> I know I sure as heck couldn't.
[17:06:00] <anonnumberanon> But hey, I have to be able to sound smart about it for an interview robotics actuator company next Monday.
[17:06:29] <Snert_> laudible goal/reason.... good luck to ya.
[17:06:50] <Snert_> never know, they may want someone that doesn't know quite as much.
[17:07:27] <anonnumberanon> I hope so. I don't want to oversell myself either and get fired after a few months.
[17:09:57] <z64555> its... a DC motor
[17:10:05] <z64555> you've got a stator, a rotor, and brushes
[17:10:37] <anonnumberanon> Okay thanks now I know everything.
[17:10:38] <anonnumberanon> lol
[17:10:40] <z64555> the basic designs use 2-pole magnets
[17:10:43] <anonnumberanon> no look:
[17:10:53] <anonnumberanon> How do you make a cheap strong durable DC motor.
[17:10:54] <z64555> some have coils aroudn the magnets to adjust their B-field
[17:10:58] <anonnumberanon> You have one hour...
[17:11:00] <anonnumberanon> lol
[17:11:15] <anonnumberanon> (everything must be done in house)
[17:11:22] <z64555> what tools do we have
[17:11:31] <z64555> gotta have at least a lathe
[17:11:45] <anonnumberanon> Yeah all the machining tools needed.
[17:11:56] <Snert_> failure might be zactly what they want. Means you will learn.
[17:12:17] <z64555> ok. so rotor's made from laminates. you align the laminates together and use a lathe to balance the rotor
[17:13:05] <z64555> laminates are usually just punched/stamped from a sheet
[17:13:28] <z64555> think they're just glued together. some might have rivits
[17:13:57] <z64555> brb
[17:14:44] <anonnumberanon> I'm at the library looking all this up.
[17:14:55] <SpeedEvil> why not buy them?
[17:14:58] <anonnumberanon> There is an amazingly low amount of books about this.
[17:15:17] <anonnumberanon> SpeedEvil, Too expensive, they're trying to make their own now, they buy from outside.
[17:15:18] <SpeedEvil> You absolutely can't make things cheaper than a hundred billion dollar industry
[17:15:21] <anonnumberanon> (Maxon)
[17:15:34] <SpeedEvil> yeah - well - that's your problem.
[17:15:41] <SpeedEvil> Don't buy from maxxon.
[17:15:51] <SpeedEvil> Literally any vendor will be cheaper.
[17:16:12] <SpeedEvil> Perhaps needing some additional work to get it doing what you want.
[17:16:35] <anonnumberanon> What others are there?
[17:17:15] <SpeedEvil> https://www.google.co.uk/search?site=&source=hp&q=electric+motor&oq=electric+motor
[17:18:02] <SpeedEvil> What you need depends on teh design of what it's going to go into, torque, RPM, gearing, ...
[17:18:27] <z64555> and this is before getting into brushless designs
[17:18:27] <anonnumberanon> duh..
[17:18:50] <anonnumberanon> I think brushless spins too fast.
[17:19:05] <SpeedEvil> http://www.hobbyking.com/hobbyking/store/__56935__Turnigy_9014_105kv_Brushless_Multi_Rotor_Motor_BLDC_.html
[17:19:11] <SpeedEvil> 2000RPM max, 20Nm
[17:19:21] <SpeedEvil> 420g
[17:19:48] <SpeedEvil> (will need extra cooling if you use it at 20Nm and 0RPM)
[17:20:08] <z64555> what's that force rating from tho
[17:20:15] <z64555> at stall speed?
[17:20:21] <SpeedEvil> z64555: take watts, and divide RPM by power
[17:20:32] <SpeedEvil> err - divide RPM by power
[17:20:43] <SpeedEvil> Out pops torque at max RPM
[17:20:51] <z64555> ok
[17:21:10] <z64555> that doesn't give the stall torque
[17:21:30] <SpeedEvil> No, it doesn't.
[17:21:45] <SpeedEvil> But for brushless, stall torque is quite a bit higher than max operating torque
[17:21:54] <SpeedEvil> But for brushless, stall torque is quite a bit higher than max operating power torque
[17:22:40] <z64555> now I want to learn about motor design. lol
[17:22:59] <SpeedEvil> The above is very approximate only, but is indicative.
[17:24:06] <SpeedEvil> designing a motor and gea\
[17:24:14] <SpeedEvil> ]rbox for an app is pretty easy
[17:24:18] <z64555> 4:43:51 PM - anonnumberanon: How do you make a cheap strong durable DC motor.
[17:24:29] <z64555> Troll answer for that would be: Use an AC motor
[17:24:30] <SpeedEvil> it only gets hard if you need it in a very compact package
[17:24:47] <anonnumberanon> I need to get a force figure.
[17:24:51] <anonnumberanon> To start from
[17:25:04] <SpeedEvil> z64555: yeah - but if you're comparing with maxxon to start with - damn near anything is cheaper
[17:25:05] <anonnumberanon> okay 500 lbf, what is lbf?
[17:25:22] <z64555> pounds force
[17:25:22] <SpeedEvil> anonnumberanon: you are not providing any useful specs at all.
[17:25:37] <anonnumberanon> explain
[17:26:09] <z64555> He said strong, so we're assuming a high-torque motor
[17:26:37] <anonnumberanon> It's for a linear actuator, to it must lift with 500 lbf.
[17:26:54] <z64555> He also said durable, so something that won't burn up under stall load
[17:26:58] <SpeedEvil> anonnumberanon: A useful spec would have what torque and RPM are needed, with any constraints on backlash, rapid changes, ...
[17:27:06] <anonnumberanon> https://www.google.com/search?q=linear+actuator&num=30&source=lnms&tbm=isch&sa=X&ved=0ahUKEwim3NCQhYPOAhXISCYKHeNCCvsQ_AUICigD&biw=1318&bih=578
[17:27:13] <SpeedEvil> anonnumberanon: as well as what size enclosure it must fit in
[17:27:35] <z64555> ok. Linear actuators use a wormscrew drive usually
[17:27:42] <anonnumberanon> SpeedEvil, Yeah but I can't get that I don't work there yet lol.
[17:28:09] <z64555> SpeedEvil: we're talking general theory
[17:29:28] <z64555> wait, no, I was wrong, they don't use a wormscrew drive. huh.
[17:29:36] <anonnumberanon> Okay they use a BLDC.
[17:29:46] <anonnumberanon> That's all I could gather so far.
[17:30:14] <z64555> Fascinating
[17:30:57] <z64555> BLDC's have less mechanical parts to them, so there's vastly less wear and tear
[17:31:13] <z64555> only things you've got to worry about is the bushings that hold the axel in place
[17:32:38] <z64555> There's two flavors of BLDC, the outrunner and the inrunner type
[17:32:47] <z64555> The "runner" is the rotor
[17:33:51] <z64555> Outrunners tend to be lighter with relatively high torques, Inrunners are for speed
[17:34:55] <z64555> hm.
[17:35:04] <SpeedEvil> For reciprocating drive, it is more complex, as you also care about the moment of inertia
[17:35:23] <SpeedEvil> Or ratehr - the energy stored in the motor by getting up to max RPM
[17:37:15] <SpeedEvil> The above motor weighs 400g and goes 2000RPM. That is 33 revs per second. Assuming one half of the mass is rotating - 200g, and the diameter is 90mm, that is a circumferential speed of 9m/s or so. Or an energy stored of 1/2*m*v^2 = 8J or so
[17:37:35] <SpeedEvil> In principle, it can come up to speed in a handful of milliseconds.
