#robotics Logs

Jun 12 2018

01:39 AM rue_: https://www.nutsvolts.com/uploads/wygwam/NV_1103_Marston_FIGURE13.jpg
01:43 AM rue_: https://obrazki.elektroda.pl/3556779100_1372330566.gif
01:43 AM rue_: https://i.ytimg.com/vi/e-AClwxINBU/maxresdefault.jpg
03:48 AM Jak_o_Shadows: I tend to just translate words in my name
04:34 AM BitEvil is now known as SpeedEvil
03:36 PM Miyu is now known as hackkitten
03:58 PM DJuego: Hi!!
04:00 PM DJuego: I am delighed that this topic exists in the IRC.
04:00 PM DJuego: Sorry for my English.
04:01 PM DJuego: I am searching a motor with great precision and high torque.
04:07 PM DJuego: I have a great experience with Lego servo motors (EV3)... but now i need a lot more torque.
04:08 PM DJuego: This looks good:
04:08 PM DJuego: https://robokits.co.in/motors/high-torque-encoder-dc-servo-motor-600rpm-w-uart-i2c-ppm-drive?cPath=2_71_328&zenid=q8amn9rtkpa6okmtgc2qta8j74
04:10 PM DJuego: but I need recommendations and advice from experienced users.
04:10 PM DJuego: Any advice and/or recommendation? Any interesting product?
04:11 PM DJuego: Thanks in advance!
04:13 PM DJuego: I want two motors, and direct control via PC is important.
04:50 PM veverak: "great precision" "high torque" are pretty vague terms
04:50 PM veverak: "direct control via PC" is bullshit, you can handle microcontroller on the path
04:50 PM veverak: -> search for Dynamixel
04:52 PM DJuego: Thank you for your answer, veverak!
04:52 PM veverak: rue_: also, you were right, you actually can efficiently print fittings for hoses as small as 4mm inner dia
04:55 PM DJuego: I need to "motorize" a small wheel table. It needs to push the structure (the table), two motors, the battery and a laptop at least.
04:55 PM veverak: why the laptop?
04:55 PM veverak: or, what's the purpose?
04:56 PM Tom_L: he's pulling a sheldon with the portable laptop
04:57 PM Tom_L: https://www.youtube.com/watch?v=uhZFo4VMzPk
04:57 PM DJuego: My English is probably not too good in order to explai it clearly, but I will try.
04:58 PM DJuego: Sorry for the delays.
05:01 PM DJuego: This robot is part of a larger indoor positioning project based on bluetooth low Energy RSSI.
05:04 PM DJuego: The laptop has a bluetooth sniffer. The table moves the laptop in an area exhaustively for scanning the area. (position X,Y - beacons RSSI association).
05:04 PM veverak: buy two dynamixels
05:04 PM veverak: :)
05:04 PM veverak: pick the ones with 360 degree encoder
05:05 PM veverak: learn how to calculate required motor torque, so you can pick proper model
05:05 PM veverak: (you really want to understand that part of the job)
05:07 PM DJuego: Well. I admit I am not a mechanical or electric engineer. Computer Science is my field.
05:08 PM veverak: yeah, me too, does not matter
05:08 PM veverak: you can learn, there are some parts of the project that yo usimply should understand to build at least something reasonable
05:09 PM veverak: otherwise find a mechanical/eletricc engineer
05:10 PM DJuego: Okay. Accuracy in maneuvers is important. A localization device based on ultrasound allows to know the position of the table with an accuracy of 2 centimeters.
05:15 PM DJuego: The other possibility is to acquire a robotic platform already assembled.
05:28 PM z64555: if you need accurate maneuvers, you're probably going to need a fixed reference. dead reckoning usually isn't enough
05:33 PM DJuego: The mobile beacon of the ultrasonic positioning system gives me its position with a margin of error of two centimeters at all times.
05:33 PM DJuego: The idea is that given an arbitrary target coordinate X, Y in CM, the robot moves to place the mobile beacon in that destination position as close as possible.
05:48 PM z64555: ok, so you're moving the beacon around for a local reference
05:49 PM z64555: pretty sure you'll come across a drifting coordinate system
06:26 PM DJuego: z64555: Well. Obviously I have a lot to learn. :-D
06:29 PM Tom_L: https://www.banggood.com/Wireless-Bluetooth-Audio-Receiver-Digital-Amplifier-Board-With-Remote-Control-And-Microphone-p-1092594.html?cur_warehouse=CN
06:29 PM Tom_L: rue_
06:34 PM DJuego: veverak, z64555. Thank you for the help! Probably, I will go back :-)
06:34 PM DJuego: Bye, bye.
07:46 PM rue_shop5: I wonder which computers, if any have rue_shop1, 2, and 3
07:49 PM Tom_L: you should have your printers on the network
07:50 PM rue_shop5: heh
07:50 PM Tom_L: see the link i sent you
07:53 PM Tom_L: and why is a phone keypad backwards from a keyboard number pad?
07:59 PM rue_: I was wondering that yesterday
07:59 PM rue_: you would think that everyone would be using the phone layout these days
08:00 PM rue_: banggood wont take my credit card, which is good, cause I would have spent $75 on that first time I found them
11:17 PM rue_ is now known as rue_mohr
11:55 PM CBloom: What should I search for if I want a brushless motor with a built in position encoder?
11:55 PM CBloom: I want to be able to use other servo drivers with it, or make a custom one
11:57 PM rue_mohr: hmm
11:57 PM rue_mohr: not sensorless
11:58 PM rue_mohr: CBloom, maybe sensor brusheless
11:59 PM CBloom: rue_mohr: I think that term refers to lack of hall effect sensors in the motor
11:59 PM rue_mohr: sensorless does not use halls
11:59 PM rue_mohr: so they give the core a random kick and look for the magnets