#robotics Logs

Jun 17 2015

01:34 polyhydra /msg NickServ REGISTER
04:14 deshipu I will just drop it in here https://hackaday.io/project/6050-tote-affordable-spider-robot/log/19645-remote-control-with-esp8266-and-micropython
09:09 veverak torque
09:09 veverak for servos
09:10 veverak is kg for m ?
09:10 veverak I suppose that kg for cm
09:11 veverak let's say
09:11 veverak I need to move something which is around 600g
09:11 veverak up and down, for "2cm"
09:11 veverak so, to be safe
09:12 veverak let's say 3cm - 1kg
09:14 veverak so, I need, at least 2cm long arm on my servo
09:14 veverak which means, that servo that got 2kg per cm, should be ok
09:15 rue_house yup
09:16 veverak http://hobbyking.com/hobbyking/store/__16269__HobbyKing_8482_HK15138_Standard_Analog_Servo_38g_4_3kg_0_17s.html
09:16 veverak so with this
09:16 veverak I am OK ?
09:19 deshipu veverak: you know http://www.servodatabase.com/ ?
09:19 veverak no
09:20 veverak also
09:20 veverak how can I calculate speed?
09:20 veverak O:)
09:20 veverak P.S: picking servos for this http://wiki.veverak.org/Dual
09:20 rue_house degrees per second
09:20 veverak deshipu: thanks!
09:20 deshipu you don't calculate speed, it should be provided
09:20 deshipu 0.21 / 60deg @4.8v
09:21 deshipu means it can rotate 60° in 0.21s
09:21 veverak that seem fast enough
09:21 rue_house 285.71 degrees/second
09:22 rue_house 47.6rpm
09:22 verak needs to go around 60 deg
09:23 veverak 0.2s seems fast enough
09:23 deshipu there you go :)
09:24 veverak that HK15138 is not there :/
09:24 rue_house oh hobbyking... hmm
09:24 deshipu veverak: yeah, it's not updated very often
09:24 veverak hmm
09:24 veverak also
09:24 veverak I suppose it won't be exactly nice for the servo
09:25 veverak to hold 600g for some time?
09:25 rue_house be warned, thats probably a cheap servo that jitters a lot on its own
09:25 deshipu "EXTRAORDINARY servo incredible price and quality got 16 of them super ok ! Are based on the old trusted S3003 from Futaba! Excelent torque and very silent! will buy more!"
09:25 deshipu talk about positive revies :P
09:25 veverak :D
09:25 rue_house hmm
09:25 deshipu +w
09:25 deshipu veverak: btw, stay a little longer on that page without buying, you will get a discount
09:26 veverak hmm
09:26 veverak or
09:26 veverak I can visit local RC Dealer
09:26 veverak he said he likes my 3d printer
09:26 veverak it seems I could like his old servos
09:26 veverak :)
09:26 verak needs to lift no
09:26 rue_house I was not thrilled with my last hk experience
09:27 veverak and I only need to be precise when I put it back
09:27 veverak and mechanims will be designed, so "shitty" servo won't matter
09:27 veverak seems like I could use some bazar ones
09:28 veverak ouch
09:28 veverak never forgot to open your drawer!
09:29 veverak hitec hs300 there!
09:29 veverak :D
09:29 deshipu veverak: no towerpros? ;)
09:29 veverak hmm
09:29 veverak I need somethign, that will work shitty
09:29 rue_house arg, I think a seller on ebay listed something too cheap and is trying to get out of the sale
09:29 veverak but WILL work
09:29 deshipu rue_house: squeeze him!
09:30 veverak I suppose I designed it in way
09:30 veverak that as long as servo can move, it doesn't matter
09:30 rue_house your right, if you stay on the hk page, a popup comes up and offsers me the $3.36 servo for $3.12
09:30 deshipu veverak: SG90 for $1.37!
09:30 deshipu rue_house: neat, eh?
09:30 rue_house .. SG90 on ebay are $1.20 and less
09:31 deshipu rue_house: it fluctuates with the dollar price
09:31 veverak deshipu: ?
09:31 deshipu rue_house: also, only if you buy 100 of them
09:32 veverak too weak
09:32 veverak :D
09:32 deshipu veverak: that's what she said
09:33 veverak :))))
09:33 veverak lifting nema17 motor
09:33 rue_house wtf...
09:34 veverak need some power
09:34 rue_house where are the servos I ordered... they aren't on my purchased lists...
09:37 rue_house I think ebay is making things dissapear of my purchase history again
09:44 rue_house I know I bought about 10 SG90 servos
09:44 rue_house I cant find them on ali or ebay
09:44 rue_house WTF!>
09:47 rue_house oh, amazon maybe
10:14 LiohAu rue_house: any opinion on FeetechRC servos?
10:15 anonnumberanon http://webcast.amps.ms.mit.edu/i/institute/2012-2013/6.270/
10:15 anonnumberanon to watch during transportation
10:17 anonnumberanon rue_house, have you looked/used openservo? I can't determine if that's useful or not for making cheap, torquy servos.
10:19 deshipu anonnumberanon: openservo boards are extremely expensive for what they do
10:19 anonnumberanon oh these are micro servos
10:19 anonnumberanon deshipu, that is what I got to when I researched it.
10:19 anonnumberanon Plus I was wondering what their added value was.
10:19 anonnumberanon Except for maybe rebuilding servos? changing certain settings?
10:20 deshipu well, the servo is the same, you just get all the control and feedback stuff
10:20 deshipu you can check the load on the servo, change its speed characteristics, read current position, etc.
10:21 anonnumberanon In any case what I need is about 40 servos that give (in the units used for that sort of hardware) about 10 to 14 kilograms*centimeters of torque, and I need to be able to make them for super cheap, and better if they last longer, by super cheap i mean if they were about$10-15 that would be awesome.
10:21 deshipu each, or together?
10:21 anonnumberanon each
10:21 deshipu ouch
10:22 anonnumberanon together at that price would probably revolutionize the world of robotics hehe
10:23 deshipu I meant the torque
10:24 anonnumberanon preferably 14 kg.cm each because I am trying to replicate the setup on a robot that I want to build that a company is already selling as a kit, for an extreme price
10:27 anonnumberanon their servos are $100 separate, 17 of them with the rest of the robot parts for complete kis is $1600
10:27 deshipu sounds about right
10:27 anonnumberanon HKR_3HV
10:27 anonnumberanon KHR-3HV
10:27 anonnumberanon I meant...sorry
10:31 deshipu one thing you can do is replacing the servos with normal motors with gearboxes and encoders, and drive them yourself with some mosfets from the main microcontroller board
10:31 deshipu of course that increases the complexity
14:52 blib is there a place where I could search for a robotic platform and design 4 wheel robots which can carry certain payload - and it recmmends motors/motor controller to use?
15:06 deshipu blib: I don't think so
15:11 SpeedEvil Sounds an expensive shop
15:11 SpeedEvil Plus, it's almost meanigless.
15:12 blib deshipu: if I want a 10kg payload robot, how do I get the wheel, motor and motor controller I need?
15:12 SpeedEvil If I want a robot to move at 1mph over a smooth concrete floor with skateboard wheels, that may use a thousanth of the power of the same weight of robot which is wanted to move up a 30 degree grassy slope at a runn
15:13 deshipu blib: build it, test it, and rebuild if it doesn't work...
15:15 SpeedEvil understandig the basic physical limits - mgh
15:15 SpeedEvil 10kg * 1m/s upwards *9.8m/s^2 = 100W
15:16 SpeedEvil A good estimate can be gotten of how fast the unmotored thing slows down
18:15 cambazz hello, i need to develop a hardware quadrature encoder interface, basically something that counts pulses and outputs them on i2c
18:30 anonnumberanon I bought a robosapien without remote control for $25 at electronics recycling :)
19:15 squirrel2 nah
19:15 squirrel2 firewalls are tricky
19:15 orlock nah
19:15 orlock deny any any and log
19:15 orlock done
19:15 orlock or
19:15 orlock just cut the damn cable
19:16 veverak 187 lines of script!
19:16 veverak :D
19:16 orlock unless you have had an auditor sit next to you and go through your rules
19:16 orlock line by line
19:17 orlock examining the business justifications for each ALLOW
19:17 orlock and trying to force you to tighten down the source port ranges for each one
19:17 orlock you have nothing to complain about
19:17 veverak nah
19:17 veverak I have
19:17 veverak most of the stuff I use stopped working
19:17 veverak but meh
19:18 lock just got notice of a security audit at $ne
19:18 orlock thank god its only internal
19:19 veverak :D
19:29 Loshki orlock: if they never took your fingerprints, don't worry about it.
19:30 orlock network/it security ausit
19:30 orlock audit
19:30 orlock though, the last one did require a police background check
19:30 orlock Loshki: unrelated, but the engineers here were actually after blood samples for "testing" last month
19:37 veverak deployment on virtuals done
19:37 veverak seems like it could work :)