#robotics Logs

Feb 20 2014

00:09 e_house is too tired to scream right
00:10 MrCurious heh. meh... whats the point
00:25 MrCurious rue_house: still conscious?
00:26 MrCurious what you think of this as a basis for a robot elbow joint? http://www.allelectronics.com/make-a-store/item/DCM-444/Right-Angle_Drive_Gear_Motor/1.html?gclid=CNiJ55-F2rwCFdGBfgoddzEADQ#12493.flv
00:26 MrCurious swap out the dc motor for a stepper
01:13 rue_house no, put an encoder on it and run it in a servo loop
01:16 MrCurious http://www.thestar.com/news/canada/2014/02/18/justin_trudeau_rolling_papers_prove_a_big_hit.html
01:16 MrCurious oh canada...
01:17 MrCurious how long until its referred to in canada as "twisting a trudeau"...
05:24 Jak_o_Shadows https://www.dropbox.com/s/pfq5w6tyv4n88ch/ik.PNG Inverse Kinematics Hoy!
05:25 Jak_o_Shadows Top left is ccd, top right is jacobian transpose, bottom left is jacobian psuedo inverse
10:35 zero_coder hey , i got a 12V 7Ah pb-acid type rchargable type battery
10:35 zero_coder need help connecting it with raspberry pi
10:36 zero_coder hey , i got a 12V 7Ah pb-acid type rchargable type battery.need help connecting it with raspberry pi
10:40 Cylta zero_coder: what voltage does the RPi need?
10:42 armyofevilrobots It's a USB connector, so 5.
10:44 armyofevilrobots You might be able to find an automotive 12V step down with a switching power supply at your local auto parts place. That'll do the job nicely.
10:44 armyofevilrobots just open it up and pull off the extraneous cigarette lighter plug.
10:44 GuShH_ hm?
10:45 GuShH_ if you want noisy ass shit 5vdc go ahead, do that.
10:45 Cylta car 12v-5v cigarette supply usually gives only about 400mA, what may be not enough.
10:46 GuShH_ Cylta: assumptions
10:46 Cylta how much power does the RPi need?
10:47 GuShH_ that depends.
10:50 zero_coder Cylta: sorry , i was afk
10:50 zero_coder uses micro usb charger
10:51 zero_coder armyofevilrobots: yep
10:51 zero_coder armyofevilrobots: i am trying to make a robot, a small AI
10:51 zero_coder :P
10:52 zero_coder Cylta: ?
10:53 Cylta check how much current you need, use step-down converter.. =)
10:54 zero_coder Cylta: what about the motors and the other IC's
10:54 zero_coder ?
10:54 Cylta I'd recommend make a separate supply for them
10:54 zero_coder Cylta: and how do i recharge the batteries?
10:55 Cylta just find any 220-13...16V
10:55 Cylta converter
10:56 zero_coder sorry, i didnt get you
10:56 zero_coder i am pretty noob at electronics
10:57 Cylta take any battery charger, connect it to the battery. I don't see a problem here
10:57 zero_coder Cylta: okay :)
10:57 zero_coder all i have to do is step it down to 5v?
10:57 Cylta yes
10:58 Cylta if you are paranoid, you may add a capacitor to the end of that step down converter
10:58 zero_coder lol
10:59 Cylta are you doing some sort of autonomus robot?
10:59 zero_coder Cylta: yep , thats what i want to make
10:59 Cylta and now you are like "wow! I have battery and a RPi! let's make something!"? =)
11:00 zero_coder yep
11:00 zero_coder :)
11:00 zero_coder i know a bit of programming lol , thats all
11:01 Cylta good luck with that =)
11:01 zero_coder thanks :)
11:01 zero_coder but , seriously i need help with electronics
11:03 Cylta 220v - (220v to 12...20V converter aka battery charger) - battery - (12v to 5V, aka step down converter) - RPi
11:07 zero_coder but , there should be some sort of circuit to put it all together , right?
11:08 zero_coder Cylta: what kind of robots do you make?
11:09 Cylta zero_coder: nope, you do not need a circuit. you lways can use a ducktape! =) I don't do them
11:10 zero_coder Cylta: okay :)
11:11 zero_coder Cylta: just input 12-20 volt into battery and it will charge?
11:11 Hukka Ummm
11:11 zero_coder Hukka:
11:11 zero_coder ?
11:12 Hukka What kind of battery are we talking about?
11:12 Hukka Lithium?
11:12 Cylta Pb-acid
11:12 zero_coder lead-acid type rechargable battery Hukka
11:12 Hukka Oh, ok
11:12 zero_coder the one had in my pc's UPS
11:12 Hukka Well those are pretty fool proof
11:13 Cylta zero_coder: sure it will. what else it can do? =) you just have to apply voltage that is bigger on 1-2V than a battery, and it will charge it.
11:13 zero_coder Cylta: cool , thanks
11:13 zero_coder :)
11:13 zero_coder Cylta: what about the l293D motor driver IC?
11:14 Cylta never heard of it. datasheet?
11:14 zero_coder http://www.engineersgarage.com/electronic-components/l293d-motor-driver-ic
11:14 zero_coder Cylta: also the battery is too heavy, what kind of motors and wheels will i neeD?
11:14 Hukka zero_coder: If electronices is not really your thing, you'll likely want a full ready made motor controller, not just the ic
11:15 Hukka Something that includes all the other parts so you can just plug in the motors, batteries and your logic
11:15 zero_coder Hukka: i want to learn :)
11:15 Hukka Seems like you already have plenty to learn
11:16 zero_coder Hukka: yep :) . need to learn AI :)
11:16 Hukka You don't need to start etching your own pcbs in your first project
11:16 zero_coder Hukka: first thing is cant really afford a lot
11:16 kka s
11:17 Hukka I've heard this story before
11:17 zero_coder lol
11:17 zero_coder besides, my domain is programming . :P
11:17 Hukka Anyone ever told you that big robots usually cost more than smaller ones?
11:17 Cylta zero_coder: calculate total weight of your robot, and acceleration that you want.efficiency of motors is about 60-80%, efficiency of wheel propulsion is close to 100%. So, using e=mv^2/2 you can get speed/acceleration and decide is it enough or not.
11:17 zero_coder lol
11:18 Hukka So if you start from habing to move that big ass ups battery aroung, you are already losing
11:18 zero_coder seems like i should get a. small rechargable battery
11:19 Cylta zero_coder: nah, not much difference =) just use what you have
11:19 Hukka If you want to learn AI and go pretty cheap, get a robot kit that includes all the parts except batteries, and which uses NiMhs
11:19 Cylta 7Ah 12V weight just about 700g.
11:20 Cylta if you are not planning to fly with it
11:20 zero_coder Hukka: i have got a rpi with me
11:20 zero_coder Cylta: lol
11:21 Hukka Which isn't enough to interface with sensors and stuff
11:21 Hukka For one thing the timings aren't good enough for many, and other is that you simply run out if IO
11:21 zero_coder i just need to connect 2 wheels with it
11:21 Hukka You are going to do AI with a blind robot?
11:22 zero_coder Hukka: there is a camera port on it
11:22 zero_coder inbuilt
11:23 zero_coder i just need to connect a mic and a speaker
11:23 zero_coder thts all i need for now
11:27 zero_coder Hukka: what should i do?
11:27 zero_coder Cylta: ?
11:29 Hukka Well, I told you my opinion. Go break a leg *shurgs*
11:29 Cylta zero_coder: I would connect 2 wheels at the back with a motor, one turning wheel in front without motor but that is able to turn
11:30 zero_coder Cylta: okay
11:30 zero_coder what motors?
11:30 zero_coder Hukka: http://international.switch-science.com/catalog/1550/
11:30 Cylta zero_coder: what weight and acceleration you are planning to have?
11:31 zero_coder Cylta: around 800 gms including battery
11:32 Cylta so, let's take 1200g =)
11:32 Cylta and acceleration?
11:32 zero_coder okay
11:32 zero_coder Cylta: its my first robot, i dont know
11:33 zero_coder Cylta: u are the man :)
11:34 zero_coder Cylta: ?
11:35 GuShH_ zero_coder: rue the man
11:36 Cylta have no idea. walking person have a speed of 2m/s. let's take this speed as a starting point. And acceleration to this speed within 3 seconds. then you will need 1.200*2^2/3/0.7= 2.3 watt =)
11:36 zero_coder GuShH_: how much accelration do you need?
11:36 zero_coder o_0
11:36 zero_coder Cylta: cool
11:36 GuShH_ hm?
11:36 GuShH_ over 9000.
11:37 zero_coder GuShH_: are u planing for time travel ?
11:37 GuShH_ obviously.
11:37 zero_coder 2.3 watt motor?
11:37 GuShH_ that's spent energy
11:37 Cylta zero_coder: include some energy loss due to friction in gears (10%) and wheels-ground contact..
11:37 GuShH_ you assume your motor is 100% efficient
11:37 Cylta no, that's motor input pwoer
11:37 Cylta I already calculated 0.7 eff of motor
11:38 Cylta but such small motors have efficiency of about 0.3
11:38 GuShH_ you forgot to account for dissipation of wires
11:38 GuShH_ temperature and the drift on the power source
11:38 GuShH_ and fucking planet alignment
11:38 Cylta 1.200*2^2/3/0.3/0.9/0.8 = 7.4W
11:39 GuShH_ Cylta: unlabeled values get you shot in the head in some countries.
11:39 Cylta for a small motor, gers, pulse power supply
11:39 zero_coder :P
11:39 GuShH_ oh yes this variable I just pulled out of my arse.
11:39 GuShH_ this other one out of my left ear
11:39 Cylta 1.200kg * 2^2m\s / 3sec / 0.3motor eff / 0.9 gears eff / 0.8 supply eff = 7.4W
11:40 GuShH_ zero_coder: start building, figure it out as you go, otherwise you'll become a chair potato who only pretends to do robotics but all he ever does is run simulations and watch anime.
11:40 Cylta GuShH_: hey, don't you like anime?
11:40 GuShH_ wearing nothing but his week dirty underwear
11:40 GuShH_ nope
11:40 GuShH_ Cylta: It was a mere assumption.
11:40 ro_coder is conf
11:40 GuShH_ zero_coder:hahaha
11:41 GuShH_ zero_coder: what tools and materials do you currently have?
11:41 zero_coder GuShH_: a soldering gun :P
11:41 zero_coder a raspberry pi
11:41 zero_coder and a battery
11:41 zero_coder got it from my UPS
11:41 GuShH_ so lead acid, gel?
11:42 GuShH_ how are you going to charge it, to begin with?
11:42 GuShH_ you'll need at least a float charger.
11:42 GuShH_ lay out your requirements first.
11:42 GuShH_ then based on your budget figure out the most efficient platform to build
11:43 mendax hey
11:43 mendax i just got disconnected
11:43 mendax sorry
11:43 GuShH_ ok, and you are?
11:43 mendax zero_coder:
11:43 mendax :P
11:43 GuShH_ why is your nickname not zero_coder then :p
11:43 GuShH_ [14:24] GuShH_: so lead acid, gel?
11:43 GuShH_ [14:25] GuShH_: how are you going to charge it, to begin with?
11:43 GuShH_ [14:25] GuShH_: you'll need at least a float charger.
11:43 GuShH_ [14:25] GuShH_: lay out your requirements first.
11:43 GuShH_ [14:25] Duzz_ (~Duzz@24.69.208.202) is now known as Duzz
11:43 GuShH_ [14:25] GuShH_: then based on your budget figure out the most efficient platform to build
11:43 GuShH_ [14:26] mendax (~zero_code@115.244.212.44) has joined
11:44 mendax disconnected and now i cant use the nick
11:44 GuShH_ oh it's ghosted
11:45 mendax GuShH_: a 220
11:45 mendax a 220 - 12+v converter to charge it
11:45 GuShH_ mendax: not the smartest idea
11:45 GuShH_ anyway do /msg nickserv ghost zero_code
11:45 GuShH_ bah not anymore
11:46 zero_coder GuShH_: its fixed
11:47 zero_coder GuShH_: so what else do you propose?
11:52 zero_coder GuShH_: ?
11:56 zero_coder gone?
12:12 GuShH_ zero_coder: always
19:31 robotustra че за гавно
19:34 Cylta robotustra: it's english channel, afaik
19:35 Cylta don't swear :P
19:36 robotustra in english I can't express my fillings
19:36 Cylta lol. and what happened?
19:37 robotustra net split
19:37 Cylta doh.. I see it every day..
19:37 robotustra I see it rarely at myplace
21:20 rue_more ????? ?? ???????? ????, ????? ? ?????? ??-?????????
21:20 rue_more ?????. ????? ???? ?? ????????
21:37 rue_more mmm atmega88 $2ea 10
21:38 rue_more 8g servos, $2.50ea, 10
21:38 rue_more uln2803 25c ea, 100pcs
21:38 rue_more :) happy day
21:38 Faek What's the delivery time like?
21:38 rue_more 22 days typ
21:57 rue_more I'm being told I cant keep turning the antigravity genorator upside down and dialing it all the way up for wringing out water from laundry...
21:57 rue_more "not proper use" pfff
21:57 Faek What do they define as proper use then? That seems a perfectly legitimate use to me
21:58 rue_more I know eh?
21:59 robotustra rue_more: how are servos?
21:59 rue_more I can understand them not liking me pranking people by putting it over their bedroom door, but reall?
21:59 rue_more I havn't tried them yet
21:59 rue_more I expect they are junk
21:59 rue_more so I'll be nice to them
22:00 robotustra how is your program?
22:00 rue_more or tear out their guts and use them for other stuff
22:00 rue_more the mind washing or the servo firmware?
22:00 robotustra like walking humanoid robot?
22:00 robotustra 50 cm?
22:00 rue_more with only 10 servos? not likey
22:00 robotustra very likely
22:00 rue_more hobby servos are tooo twitchy for bipeds
22:01 rue_more or anything walking
22:01 rue_more if I'm gonna do soemthing, I'm gonna do it right
22:01 rue_more well
22:01 rue_more dont ask about eh duct tape on the anti-gravity plate
22:04 MrCurious hmmmm duct taping fine china to the ceiling...
22:04 robotustra https://www.youtube.com/watch?v=-Vg-BdXps50
22:04 MrCurious you get antigravity plating AND duct tape in a single deployment
22:09 rue_more progress report: cleaning room: found mop
22:10 rue_more more progress to follow tommorow.
22:10 rue_more hmmm
22:14 rue_more so how do I call for completion of a packet that I dont know if has been fully recieved yet?
22:14 rue_more ooh wait, maybe I dont have to not know
22:14 rue_more Commands:
22:14 rue_more 0 listen (servo number) 256 = all {always obey command} // sticks through listen once
22:14 rue_more 1 ignore (servo number) 256 = all {always obey command} // overrides listen once
22:14 rue_more 2 One Time listen (servo number) {always obey command}
22:14 rue_more 3 set flags (flags) (+toggle debug) { bitwise obey }
22:14 rue_more 0 enguage cached position {always obey command}
22:14 rue_more 1 turn servo on {obey if listening}
22:14 rue_more 2 turn servo off {obey if listening}
22:14 rue_more 3 set cmdpos to curpos {obey if listening}
22:14 rue_more 4 set servo position (position) {obey if listening}
22:14 rue_more 5 set cached position (position) {obey if listening}
22:14 rue_more 6 get servo current (servo number) {servo number}
22:14 rue_more 7 get servo position (servo number) {servo number}
22:14 rue_more 8 send device model (servo number) {servo number}
22:15 rue_more only some of these commands CAN reieve 17 bit values
22:15 rue_more 4, 5
22:15 rue_more uh, thats it
22:15 rue_more OR I make a flag for 17 bit mode
22:16 e_more th
22:18 robotustra too much senseless commands
22:18 robotustra protocol is too complicated
22:22 rue_more no its not, it allows for synchronous motion of lots of axies
22:23 rue_more my interpolator can handle 65536 axies, so if I had 256 robots with 256 axies, they could move as one unit
22:23 rue_more completely synchronized
22:24 robotustra it can be done through broadcast command
22:25 robotustra but not through complicating protocol
22:25 rue_more with what I have there you can preload the positions and trigger them with a broadcast
22:26 rue_more so there is no positional specification delay time
22:26 robotustra anyway you should send the trigging signal
22:26 robotustra or sync signal
22:26 rue_more 3 set flags (flags) (+toggle debug) { bitwise obey }
22:26 rue_more <rue_more> 0 enguage cached position {always obey command}
22:27 robotustra where the command "save preset position"
22:28 rue_more 5 set cached position (position)
22:28 robotustra what is device model?
22:29 rue_more its basically a firmware serial number
22:29 rue_more its so i can operate different servos ont eh same buss
22:30 robotustra serial number != device address
22:30 rue_more correct
22:31 rue_more to sweep for servos, you call them to attention one at a time and ask for the serial number, no reply = nobody home
22:31 rue_more there in a pin on the hardware that sends the base address of the servo to the serial port in plain ascii
22:32 robotustra it will be collisions
22:32 robotustra when you'll have 65535 servo
22:32 rue_more nope
22:32 rue_more only 256 on a bus
22:32 rue_more 64k would have 256 busses
23:13 MrCurious i now wonder what 65535 servos sound like
23:15 rue_more hwo many batteries do you think it would take to run 200 hobby servos, not hat I'm talking about hobby servos at all
23:16 MrCurious that would depend on the size of the battery and servos
23:16 rue_more think 50W servos min.
23:16 MrCurious somewhere between 1 and 200 i would expect, for some duration of time...