#robotics Logs

Jul 02 2014

00:02 Hyratel uh yeah
00:03 Hyratel IK is how you find a solution for moving a three segment armature to a specific point in space
00:03 Hyratel ie, touching your nose
00:09 rue_mohr2 yea, you still have to know the geometry of your robot
00:09 rue_mohr2 so, have any measurements?
00:35 MrCurious i LOVE it when a design jells
00:36 MrCurious would have been nice before i bought the wrong inventory of materials
02:49 GuShH rue_more: you know that oiler bottle they give you with the lathe... I was using it to add cutting oil to an endmill, when BANG it caught one of the flutes and shot across the room, when I retrieved the bottle the nozzle was entirely destroyed, also left a mark on my steel part :( but back to the bottle, turns out the tube is brass, plated (nickel?) so I cut the broken nozzle, chamfered outside and inside edges (by hand, since
02:49 GuShH it's not straight) and then machined a steel adapter made to press-fit onto the tube and on the other end threaded M6! so now I can use different size / shape nozzles.
02:50 GuShH the original one wouldn't work properly with the oil ports, the new one does.
02:50 GuShH I have a steel one I use for most things but it's nice to have spares.
04:55 deshipu inverse kinematics squats: https://www.youtube.com/watch?v=LUIlRrgGzjI
04:56 deshipu I'm way more excited about it than I should be
05:07 Jak_o_Shadows Don't worry: I was waaay excited about the robot arm IK simulation
08:53 rue_more GuShH, mine is plastic
10:46 GuShH rue_more: all plastic?
10:47 GuShH I mean the nozzle with the black thread, the tube is brass
10:47 GuShH threaded with a cap
10:47 GuShH but the bottle is plastic (shitty)
10:47 GuShH any oil bottle meant to be sqeezed is going to be made out of plastic these days, cheaper than having a whole pump assembly and a metal container!
10:48 ShH wonders if he could make his own oil
12:24 madis_ just steal a syringe from a druggie
12:25 madis_ or a phat one from a veterinarian.
13:00 esakish Steal from a druggie? lel aids
14:58 poli Hallo my good people of #robotics!
15:15 SlaveToTheSauce greetings
16:46 deshipu first stable creep! https://www.youtube.com/watch?v=re0oMx5ZsZQ
16:46 deshipu (yes, I need to make the swinging to the sides more gradual)
16:47 SlaveToTheSauce shake dem hips
16:47 SlaveToTheSauce nice progress man
16:47 deshipu until I get bored with it ;)
17:02 poli deshipu: nice!
17:46 somebub show text
17:51 somebub ok so i am a guy that has become fed up with sbc and microputers endevered to power more legacy type boards with less power
17:51 Hyratel somebub, SBC? please expand on your TLAs the first time you use them
17:52 somebub single board computers running embedded software
17:53 Hyratel ok?
17:53 Hyratel your post was a keyboard smash, gonna need more information if you want help
17:54 somebub i think that i have found a way around the off board problems lag time by putting more power computing onboard
17:56 ShH fr
17:56 GuShH I feel dumber after reading those two sentences
17:56 Hyratel GuShH, yeah really
17:56 ShH hides behind Hyr
17:56 Hyratel somebub, please slow down. stop. back up. explain in full
18:00 somebub the most powerfull current robot computers are basicly thin clients in processing power .but with out the abillity to run emc or mach native .onboard vission and kinenematics is out too
18:02 Hyratel somebub, please corral your thoughts more coherently
18:03 Hyratel I still don't know what you're trying to do
18:05 GuShH Hyratel: must I coffe get some asleep fall before I do.
18:05 ShH racks sho
18:05 GuShH somebub: What's your native language?
18:05 GuShH :)
18:06 somebub i need to know of an archetexture with piniouts that go to sides of the chip instead of balled at the back
18:07 somebub i dont want a soc because of portabillity
18:07 GuShH I give up.
18:07 GuShH This is what happens when you use arduinos for way too long.
18:11 somebub i want to cool the chips for over clocking and want the surface area of both sides to be sinkable
18:12 SlaveToTheSauce lol
18:14 flash0777 Hi all, would like to build a rover on the cheap. I want to start with attaching some motors to a board, use the rasp pi that i already have and program the pi to spin the motor for starters. Would it be cheaper to buy motors from places that sell RC components or are there better or cheaper alternatives. Appreciate any input you can provide to get me started. I have solid programming background. But moderate to little real hardware background if that
18:14 flash0777 matters. And almost zero mechanical knowledge.
18:14 SlaveToTheSauce ebay
18:15 GuShH http://blogimages.thescore.com/nhl/files/2014/03/opie.jpg
18:15 Hyratel flash0777, a raspi is ill-suited to realtime robotics
18:15 Hyratel do you have an arduino?
18:18 flash0777 I don't. Is Arduino better?
18:18 flash0777 Guess I can get one of those...
18:19 flash0777 just curious why is the ard better than pi?
18:22 flash0777 i'd like the wheels to turn +-90 degrees. Any suggestions on what kind of contraption i can put the wheels on?
18:27 somebub i know it is daunting but think ofit like a cluster where all the cpus share two heat sinks the one in the midle is big and has flat sides with the chips pressed against it by the out side ring of heat sinks both are cooled actively by a refrigerant
18:30 somebub i ll get my coat
18:35 Loshki flash0777: I went to 'the goodwill' & for $2.99 picked up an rc control car minus the remote. I plan to add an arduino & a nrf240L+ and make it mop the floor
18:37 flash0777 Loshki, whats the nrf for? I googled and it looks like an RF transceiver
18:37 Loshki flash0777: check out instructables.com, hackaday.com for ideas too.
18:38 flash0777 Is "the goodwill" like a Salvation Army?
18:39 Loshki flash0777: the nrfs are to make it radio controlled using a pair of arduinos and a pair of nrfs (there are cheaper ways I'm sure). They are perfect for the hardware impaired, no soldering required...
18:39 flash0777 cool
18:40 SlaveToTheSauce there isnt really a cheaper option when those nrf modules are ~$1
18:41 Loshki flash0777: Yes, goodwill is like salvation army. Always lots of rc toys to choose from 'cos kids break them or lose the remotes. The motors almost always work (take a battery with you?) as the cheap plastic breaks first. I also take apart used roombas :-)
18:42 flash0777 very cool. Thanks Loshki! I gotta step out for a couple of hours. Later
18:42 Loshki SlaveToTheSauce: I know nrfs are cheap, but you have to drive them with something...
18:42 Loshki flash0777: any time...
18:43 SlaveToTheSauce ya so another dollar's worth of microcontroller and you're set
18:44 Loshki SlaveToTheSauce: well, $3 for an atmega328, plus a couple of mosfets to drive the motors. Not too bad, but also not a lot of pins leftover...
18:45 Hyratel Loshki, what are you doing with a couple of FETs that would use up most of the pins on a mega328
18:46 SlaveToTheSauce http://workman-industries.net/images/radiobridge.jpg
18:46 SlaveToTheSauce cant remember the exact count but there were at least 6 free gpios on this
18:48 Loshki Hyratel: I'm also using nrf240L+, and it uses a fair number of pins (6). Then one pin for each of 2 mosfets driving the motors. The one pin each, say, for sensors. Starts to add up...
18:49 SlaveToTheSauce avr is a dead end in any case imo. you can get an stm32f1 in a qfp100 package for about the same price as the 328
18:49 Hyratel Loshki, I2c for sensors
18:49 Hyratel what are all those pins doing anyway
18:49 Hyratel you could use an i2c io buffer
18:50 Loshki Hyratel: nothing, currently, but I want roomba-like functionality, which means a ring of cliff sensors and bumpers, and anything else I can think of...
18:51 Hyratel no i mean
18:51 Hyratel on the nrf
18:51 Hyratel if you only have two data pins, I/O, then the rest could be IO buffered
18:51 SlaveToTheSauce CE, NSS, MISO, MOSI, SCK, INT
18:51 Hyratel CE, NSS, INT?
18:52 SlaveToTheSauce chip enable, not slave select, interrupt
18:52 Hyratel ah
18:52 SlaveToTheSauce i guess you COULD use a shitty serial io buffer for them but it'd make your communication slow as balls
18:52 Hyratel so not really delegatable
18:53 Loshki Hyratel: oh! SPI + CE + IRQ
18:54 Loshki Hyratel: some clever chappy has a hack to save a pin to make it usable with an attiny: http://hackaday.com/2014/02/16/nrf24l01-using-3-attiny85-pins/
18:54 SlaveToTheSauce uh
18:54 SlaveToTheSauce don't do that
18:55 SlaveToTheSauce you cant reliably use a diode to drop a supply voltage like that
18:57 Loshki SlaveToTheSauce: they talk about biasing the diode briefly in the comments, but it's beyond me...
18:58 SlaveToTheSauce it's a pretty bad way to do it in any case, and prevents you from swapping in an amplified module etc
19:03 Loshki SlaveToTheSauce: well, it would bring the price down, but still not many pins leftover...
19:03 SlaveToTheSauce which is why the real solution is to not use a shitty and antiquated microcontroller
19:03 aveToTheSauce drops the
19:04 Loshki SlaveToTheSauce: I'm definitely interested in the stm32f1...
19:18 Hyratel SlaveToTheSauce, exCUSE me?
19:18 Hyratel which micro do you mean?
19:24 Loshki I assume it was this: http://www.newark.com/stmicroelectronics/stm32vldiscovery/stm32f100-on-board-st-link-discovery/dp/21T4023?ost=STM32VLDISCOVERY&CMP=AFC-STMICRO
19:30 Skwint wooT1
19:30 Skwint you know you asked the right question when random strangers on facebook are suggesting you commit suicide ;)
19:31 rue_more GuShH, yea, mines just a cheapo plastic squeeze bottle
19:46 GuShH rue_more: yeah. the nozzle blew up so I made one with threaded replacable tips
19:47 GuShH still useful, since plastic won't cause damage
20:05 somebub hello so who has the best bot here?
20:09 somebub kind of a juvenile question but repraps and stand alone cnc s dont count unless they are in another robot
20:10 rue_more can I enter for bot count?
20:11 rue_more somebub
20:11 rue_more http://ruemohr.org/~ircjunk/robots/robot_family2.jpg
20:11 rue_more I need to update that
20:11 somebub what can it do
20:12 rue_more which one?
20:12 somebub your favorite
20:12 rue_more I think my fav is the new arm
20:13 rue_more http://ruemohr.org/~ircjunk/robots/arm7/p1050964.jpg
20:13 rue_more arm7
20:13 rue_more http://www.youtube.com/watch?v=qZF9WJ1Ueew
20:14 rue_more it can, amongst other things, delete emails from my iphone
20:16 somebub hobby servos but cool . hve you thought about using hobby servovos to drive a double through switch to drive a gear motor to up the power. dont get me wrong i am not nocking it . it is just an i dea that keeps poping up
20:17 rue_more its the onyl hobby servo one I'v done
20:18 rue_more I did it to shot hte world how to NOT balance a whole freaking robot arm on the top of a servo horn
20:18 rue_more and int he process I got carried away
20:19 somebub wow i looked at the pic again you have been busy
20:19 rue_more there have been a lot more since
20:20 rue_more the arm shown in the family photo is 3
20:20 rue_more since are 4, 5, 6, and 7
20:20 rue_more http://ruemohr.org/~ircjunk/robots/arm5/p1030724.jpg
20:21 rue_more 5 is cool, actually made by my robotics students
20:21 Hyratel somebub, double throw*
20:21 somebub i like servos because the power consumption is less and they are more robust in that they tolerate power interuption better than step drivers but the cost of real servo drivers is too much
20:21 rue_more http://ruemohr.org/~ircjunk/robots/arm5/p1030984.jpg
20:22 rue_more http://ruemohr.org/~ircjunk/robots/sparrow1/p1040018.jpg
20:23 rue_more you never really appreciete how big a 12' robot is till you model it up
20:23 somebub yes double throw where the horn is in the middle and nothing is powered like a dryer switch
20:23 rue_more see, I just have to replace everything there with regit robot parts and I have a 12' robot
20:24 rue_more how to build a robot with 1 completel overhaul
20:26 somebub that tall on reminds me of an idea for a gardener i had using clothes lines to make a very long cnc
20:30 somebub you are have a lab not a couple of desks
20:48 somebub the new arm looks like it uses real servos on real jack screws very frankenstein . i bet those jack screws let it be still though even if there is a lot of weight on the end of the arm
20:48 GargantuaSauce <somebub> hobby servos but cool . hve you thought about using hobby servovos to drive a double through switch to drive a gear motor to up the power. dont get me wrong i am not nocking it . it is just an i dea that keeps poping up
20:48 GargantuaSauce this is really stupid don't do this
20:50 somebub do u mean the robot arm?
20:50 GargantuaSauce i mean using a hobby servo to flip a switch
20:52 somebub i think that if the switch drives a dc gear motor with an encoder on the shaft then i fail to see how the end result is not the same
20:56 GargantuaSauce the same as what, control using smoke signals?
20:58 GargantuaSauce electronic control is vital if you want to be able to even approach any sort of precision or fast response
20:59 GargantuaSauce rather than a ridiculous rube goldberg contraption that will take a quarter second to toggle
21:01 Hyratel if you want to flip a sqwitch answer this first
21:01 Hyratel is it AC or DC?
21:02 somebub there is still an encoder on the gear motor only this way i am not powering 8 servo drivers to drive 8 motors
21:02 GargantuaSauce and what good does the encoder do?
21:02 Hyratel somebub, answer the question
21:02 Hyratel is it AC or DC?
21:03 somebub does not mater they both flop polarity
21:03 Hyratel wrong
21:03 Hyratel it does matter
21:04 Hyratel what is the device you are controlling
21:04 somebub ac dc same thing differnt sides of a bridge rectifier
21:04 Hyratel then say that
21:04 Hyratel but it still does matter
21:05 Hyratel are you trying to reverse a mains drill motor?
21:05 Hyratel somebub, just answer the question and nobody gets hurt
21:05 Hyratel is it AC or DC?
21:06 somebub ac for more voltage but portable aplications are better with dc
21:06 Hyratel sorry, bad answer
21:06 rgantuaSauce checks
21:06 Hyratel are you doing AC or DC for THIS APPLICATION
21:06 Hyratel if you're reversing a motor, you'll only be using one, but not both
21:07 somebub dc to drive gear motors dc to drive the computer to check position on the encoders
21:08 Hyratel then "DC"
21:08 Hyratel would be the answer
21:08 Hyratel these are not difficult questions
21:08 Hyratel what you want here is a MOSFET H-bridge
21:08 Hyratel NOT a mechanical switch
21:09 Hyratel how many amps does the motor pull, peak?
21:09 Hyratel what is the peak current rating of the motor
21:13 somebub dc is the best yes. you can not get an h bridge that can controll large # OF DIFFERENT motors as cheaply as a cheap 32 chanell servo drive
21:16 GargantuaSauce oh i missed that this is the same guy that wants a fridge on his robot so it can overclock the onboard computer that is also not in a bga package
21:16 GargantuaSauce my life makes a little more sense now
21:17 somebub i know the cost of the servos add up but it still beats real servo drivers cost and power consumption
21:17 GargantuaSauce you are full of nonsense
21:18 Hyratel somebub, stopsign
21:18 Hyratel stopsign
21:19 Hyratel somebub, how many amps do your motors pull?
21:19 Hyratel also what voltage
21:19 ratel slaps somebub around a bit with http://www.pololu.com/
21:20 Hyratel you're going to need speed control or you'll tear apart your gears
21:20 Hyratel a switch on a servo will not give you speed control
21:21 Hyratel somebub, also, just get a Sasquatch controller
21:22 Hyratel http://www.andymark.com/product-p/am-2562.htm
21:22 Hyratel http://www.andymark.com/product-p/am-2562.htm
21:22 Hyratel woops
21:23 somebub you think about a pelteir or teg or tec or what ever you what to call them and and tell me that building the cpus around a central heat sink is dumb if your main power supply produces heat as a by product or by desighn.
21:23 Hyratel NO
21:23 Hyratel stopsign
21:23 Hyratel you do not need that for a robotic arm
21:24 Hyratel do vision processing on a single board computer networked to a robot controller running a simple microcontroller
21:24 Hyratel you are NOT going to cryo-clock your contorl board
21:29 somebub that sasquatch is nice but half an amp wont drive any thin and pull to many amps then what fries will be on one board and the pwm outputs to hobby servos
21:29 Hyratel stopsign
21:29 Hyratel sasquatch PWM => motor driver => motor
21:29 Hyratel there is no other way
21:29 Hyratel you are not controlling the motor directions with a switch and a servo
21:30 Hyratel you are not controlling the motors with relays
21:30 Jak_o_Shadows I have done that before.
21:30 Jak_o_Shadows It sorta worked
21:30 Hyratel you ARE giving in and buying a set of motor drivers
21:30 Hyratel Jak_o_Shadows, not for trying to make a robotic arm work
21:30 GargantuaSauce it seems to be the hallmark of highschool robotics classes
21:30 GargantuaSauce i've seen it done a lot
21:31 Jak_o_Shadows Well, yeah, it worked poorly. I was waiting for the motor driver to come in
21:31 GargantuaSauce they get provided an rc transmitter&receiver and a few servos
21:31 GargantuaSauce and then scrounge for the rest
21:31 GargantuaSauce with no actual embedded electronics involved
21:50 somebub 16 - PWM Outputs, all with 6V hobby servo jumper
21:50 somebub 22 - Digital I/O
21:50 somebub 12 - Analog inputs, 0V-5V
21:50 somebub 8 - Solenoid outputs, 12V-24V, 500mA each
21:50 somebub 6 - Quadrature encoder inputs
21:50 somebub i could buy one and use the hobby servo to drive the switches
21:50 Hyratel no hobby servos driving switches
21:52 somebub or better yet use the io for a step driver to do the same
21:52 Hyratel nope, you're wrong
21:52 Hyratel ding dong, you are wrong
21:53 Hyratel if you're doing any other way than using the PWM to run a motor driver, you're doing it wrong
22:28 somebub i know best practice but run it up the flag pole that is what this place is for
22:31 Hyratel cram it up your ass, maybe it'll work better
22:52 MrCurious i NEED to source something lilke this http://www.pinterest.com/pin/512495632566909096/
22:52 MrCurious anyone have ideas?
22:52 MrCurious scraatch that. they are COTS
22:55 MrCurious oh duh... i just need to bend 3 pieces of aluminum into 120deg with a pair of holes in each done
23:12 Loshki what are COTS? 1st hit on ebay: http://www.ebay.com/itm/CRL-Gold-Anodized-3-Way-120-Degree-Standard-Connector-for-1-2-Glass-/261505494040?pt=LH_DefaultDomain_0&hash=item3ce2f12c18
23:14 MrCurious Common Off The Shelf
23:15 GargantuaSauce thought it was commercial
23:16 MrCurious that too
23:17 GargantuaSauce also finish your damn cnc so you won't have to source $10 brackets!
23:17 Loshki MrCurious: thx
23:18 MrCurious realized i can just make 3 strips of thin aluminum, drill each end, then use my bending brake to make them 120 deg
23:18 MrCurious presto
23:18 GargantuaSauce oh you have a brake
23:18 MrCurious doesnt everyone?
23:18 GargantuaSauce no >:|
23:18 MrCurious they are like $30 at harbor freight
23:18 GargantuaSauce i don't have HF
23:18 GargantuaSauce or a shop space
23:19 MrCurious you need to move...
23:19 MrCurious come to america its where the tools, the room, and th talent are
23:21 MrCurious next step i suppose is how to mark out a equalaterial triangle of known dimensions. think i need a big compas for that
23:21 MrCurious ORR a board with 2 sharp screws in it
23:34 MrCurious as i suspected :) http://www.onlinemathlearning.com/construct-equilateral-triangle.html
23:35 GargantuaSauce you can also do it with a compass and ruler by starting at the centre
23:35 MrCurious true
23:35 GargantuaSauce er not compass, protractor
23:36 MrCurious but given i dont have a huge precise compas able to make a triange that is 12" exact from center point
23:36 MrCurious this method may prove easier
23:38 MrCurious aw man trying to work out the length of the 2 points on the marking tool is sflooding my mind with trig memories, right angles tales of pythagarus and girls in my 10th grade trig class
23:47 rue_shop3 Tom_itx, your programmer
23:48 rue_shop3 which 6 pin pinout does it use?