#robotics Logs

Jul 28 2014

00:04 MrCurious eliminating lurkers
00:04 MrCurious trying to bring life back to this place:)
00:07 anonnumberanon im waiting to have any good things to say
00:08 anonnumberanon im in electronics but I haven't started my move towards robotics yet
00:09 MrCurious cool
00:09 MrCurious feel free to chime in to help group-think others projects
00:09 MrCurious together we are smarter
00:09 MrCurious now lets go kick some space alien butt!!!!!
00:09 Hyratel1 OracleCarbon, I'm not sure anything under 20 lbs would be able to feild a supersoaker of decent size
00:09 MrCurious oops, sorry, wrong speach
00:10 Hyratel1 and you need a decent runtime
00:10 anonnumberanon MrCurious, I like where this is going anyhow
00:10 Hyratel1 so you need to calculate your amperage draw
00:12 anonnumberanon I just received a diy power supply kit which I assembled and it works well, as well as a Digilent Analog Discovery oscilloscope
00:12 MrCurious i just bought a $60 usb scope off of some asian site
00:12 anonnumberanon model name?
00:12 MrCurious tested it, and it worked. next step try to decide if i actually needed it
00:13 anonnumberanon lol my thought too
00:13 anonnumberanon but i have 2 university labs which will obviously happen better with it
00:13 MrCurious http://www.aliexpress.com/item/ISDS205A-PC-Based-USB-Oscilloscope-2CH-20MHz-48MSa-s-FFT-Analyzer-Data-Logger/1710938714.html i think it was this one, but do a search for usb oscilloscope
00:13 anonnumberanon (lab classes, Electronics 3 and 4 labs)
00:13 MrCurious there are MANY more options that i failed to notice...
00:14 lock is trying to sell his s
00:14 anonnumberanon http://www.jensign.com/Discovery/pulseresponse/discoveryopticalpulse.jpg
00:14 MrCurious also got a $10 logic analyzer off of ebay works greaat for decoding serial and i2c and so on
00:14 orlock MrCurious: only $10? nice
00:15 anonnumberanon link to your analyzer?
00:15 anonnumberanon this is the power supply I got
00:15 anonnumberanon http://www.amazon.com/Function-Generator-DIY-Tech-FG085/dp/B00C5UO8U6/ref=sr_1_1?ie=UTF8&qid=1406523409&sr=8-1&keywords=diy+function+generator
00:15 MrCurious something like this one http://www.ebay.com/itm/USB-Logic-Analyzer-Device-Set-USB-Cable-24MHz-8CH-24MHz-for-ARM-FPGA-/291102018494?pt=LH_DefaultDomain_0&hash=item43c7084bbe
00:15 anonnumberanon to be honest I bought this cause I love soldering hahaha
00:16 anonnumberanon that was a good few hours spent soldering too!
00:16 MrCurious more like this one http://www.ebay.com/itm/Compatible-With-Saleae-USB-Logic-24MHz-8Ch-Logic-Analyzer-for-ARM-FPGA-/231281920312?pt=LH_DefaultDomain_0&hash=item35d97a0938
00:16 MrCurious works with saleae software
00:16 anonnumberanon thats what I was gonna ask you next
00:17 MrCurious tested it decoding 9600 baud serial from a gps module
00:17 anonnumberanon huh, this looks like the stuff i did in Microprocessor class last semester https://i.stack.imgur.com/LPoWL.png
00:18 MrCurious with auto detection of serial speed
00:18 OracleCarbon Hyratel1: I'm not looking for big guns. I'm looking for compact and nimble machinery
00:18 MrCurious it gave me the text of the transmission
00:18 anonnumberanon nice
00:18 OracleCarbon I don't have to soak, just get a hit off
00:21 Hyratel1 depends if you're using a pumping soaker or an air pressure soaker
00:21 Hyratel1 a pressure soaker has a faster trigger time
00:22 anonnumberanon my dream is to make a miniature robotic factory
00:23 anonnumberanon that could dig and smelt what it digs, output resources for use in fabrication
00:24 Hyratel1 sorry bro, RTS rules don't work IRL
00:24 OracleCarbon Hyratel1: I'm looking at using an electric soaker
00:24 OracleCarbon Since it basically has indefinitely hold time, and can be operated by the onboard systems without a mechanical link that could fail
00:25 OracleCarbon indefinite*
00:25 OracleCarbon No worries about pressure bleeding off
00:26 Hyratel1 weeeell
00:26 OracleCarbon At the cost of a short delay from triggering to firing.
00:26 Hyratel1 if you roll the system yourself, it won't bleed pressure
00:26 OracleCarbon An off-the-shelf system seems like my cheapest and most reliable path.
00:26 OracleCarbon $8.50 for an electric supersoaker pistol
00:26 Hyratel1 ah ok
00:26 Hyratel1 link?
00:27 OracleCarbon http://smile.amazon.com/gp/product/B0060Y27O2/ref=s9_simh_gw_p21_d0_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-3&pf_rd_r=0PDM9G1J19PV8GFZ26E6&pf_rd_t=101&pf_rd_p=1688200422&pf_rd_i=507846
00:28 OracleCarbon Pop the housing off, mount the reservoir low in the robot (under the elctronics), get some fuel tubing from the robotics lab to replumb the system, casemate gun with variable pitch mounted on the front
00:28 OracleCarbon Done and done
00:28 Hyratel1 that looks eminently servicable
00:28 OracleCarbon One servo, and it likes having 6V on its pump
00:28 Hyratel1 and you can increatse the water tank size easily if you're going that router
00:28 OracleCarbon My bot's running 5V
00:28 Hyratel1 route
00:28 OracleCarbon I don't need the full range or pressure.
00:28 OracleCarbon So 5V should be fine
00:29 OracleCarbon My design spec is targeting a 10ft weapons range, this has 25.
00:29 Hyratel1 why only 5v?
00:29 Hyratel1 and what kind of battery?
00:29 OracleCarbon Arduino runs at 5V, drive motors run at 5V, phone charges at 5V
00:29 OracleCarbon 5V seems good
00:29 OracleCarbon 2s lipo regulated with a buck converter
00:29 Hyratel1 that doesn't mean your motors run at 5v
00:29 Hyratel1 tip
00:29 Hyratel1 don't regulate the motor
00:30 Hyratel1 control it via a FET or relay directly from Vbatt
00:30 data ag
00:30 OracleCarbon I'm not sure what my motor driver uses, just got it in the mail today.
00:30 OracleCarbon FET, I think
00:30 Hyratel1 what model? got a link?
00:31 OracleCarbon Stand by
00:31 anonnumberanon hey guys is there a comparative study about all the motorized systems available for purchase for robot-building
00:31 anonnumberanon ?
00:31 OracleCarbon https://www.sparkfun.com/products/9457
00:31 anonnumberanon like the strength of the servo, it's degree of freedom
00:32 anonnumberanon it's torque maximum, etc
00:32 MrCurious anonnumberanon: somebody has to.. the world ain't gonna turn itself into grey goo...
00:33 OracleCarbon Why is running my motors off a regulated 5V source bad?
00:34 Hyratel1 OracleCarbon, it's not bad in and of itself
00:34 Hyratel1 it's more that you're hamstringing the available amerage by doing so
00:35 Hyratel1 amperage
00:35 Hyratel1 your regulator has a limit to the current it can safely source
00:35 OracleCarbon Yeah, it's...I want to say 7.5A, but it's been a bit since I glanced at the data sheet
00:36 OracleCarbon My motors draw .3-.8A at 5V
00:36 Hyratel1 oh
00:36 OracleCarbon Two motors.
00:36 Hyratel1 you didn't give me a frame of reference
00:36 OracleCarbon Negligible draw from the Arduino.
00:36 OracleCarbon 1.5A or so from my phone if I have that charge off the system
00:37 OracleCarbon I've got 2000 mAh at 7.4V regulated down to 5V, which as I recall is equivalent to about 2900 mAh at 5V
00:37 Hyratel1 about
00:37 Hyratel1 and you're not wasting that power by using linear which is good
00:38 OracleCarbon Never was a fan of turning voltage into waste heat.
00:38 MrCurious OracleCarbon: re-test the amperage pull when the motors are held immobile...
00:39 MrCurious or under super heavy load...
00:39 OracleCarbon "Short circuit current is ~0.75A at 5V" Is that what I'm looking for?
00:39 Hyratel1 for what
00:39 Hyratel1 stall current on the motors and the pump
00:40 MrCurious not sure. just know motors that are not allowed to turn spike their amperage pull
00:40 MrCurious and why regulate the motor down to 5v from 7.4... just pwm the motor driver
00:40 OracleCarbon MrCurious: The control electronics run at 5V
00:40 MrCurious and dont lose any to heat
00:40 MrCurious yes, but the motors will run at 7.4 is my guess
00:41 OracleCarbon Yeah, it's at the upper end of their usable range though, and that 7.4 nominal battery is gonna be pushing it
00:41 Hyratel1 link to your chassis
00:41 MrCurious but if you use a pwm to driver the motor driver board...
00:41 MrCurious you can throttle the motor speed
00:42 MrCurious while not pulling the big amps through th regulator
00:42 OracleCarbon Hyratel1: https://www.sparkfun.com/products/319, the tank treads on the side of the page, and a frame I'm cutting/printing tomorrow
00:42 Hyratel1 I don't see treads
00:43 OracleCarbon https://www.sparkfun.com/products/321
00:43 Hyratel1 oh
00:43 Hyratel1 derp
00:43 Hyratel1 I was not paying attention
00:43 OracleCarbon This is much more toy-caliber than your machine
00:43 Hyratel1 i gotcha
00:44 Hyratel1 http://www.robotguy.net/goofy.jpg
00:44 Hyratel1 eeee it's cute
00:44 OracleCarbon Not quite that small
00:44 MrCurious search this site for robot chasis :) http://www.aliexpress.com/
00:45 MrCurious be warned... slow delivery, but low prices and a roboticpart store wonderland
00:45 OracleCarbon I'm converting http://www.instructables.com/id/Tankbot-Internet-Controlled-Tank-Robot/ for my purposes
00:45 orlock or dx.com
00:45 mrdata thing about these small chassis
00:45 OracleCarbon MrCurious: I have...5 days to get everything operational
00:45 Hyratel1 MrCurious, ohm yg od
00:45 orlock also
00:45 orlock nylon chopping boards
00:45 mrdata i want them to link up to climb stairs and get over other obstacles
00:45 orlock cheat, easy to work, easy to get
00:45 orlock cheap, even
00:48 OracleCarbon I'm debating between lasercut acrylic, lasercut plywood, or 3D printed PLA for the frame and mounting points
00:50 Hyratel1 LC A seems fastest, easiest and most durable
00:50 Hyratel1 you'd have to paint plywood if you're taking it out in a supersoaker fight
00:50 OracleCarbon Acrylic looks better and won't warp, but it's brittle. Plywood's tough and cheap, but warps and doesn't look as good. PLA is slow but strong, non-warping, and I can do more complicated shapes
00:50 Curious whispers aluminum .
00:51 OracleCarbon MrCurious: I can't cut aluminum neatly
00:54 MrCurious table saw + aluminum cutting blade :)
00:54 OracleCarbon That's slow and labor-intensive.
00:54 OracleCarbon I also don't have access to a table saw
00:54 MrCurious yeah
00:54 MrCurious do you have access to a laser cutter?
00:55 OracleCarbon Yeah
00:55 MrCurious cant beat that then
00:55 OracleCarbon I've got laser cutters, 3D printers, and questionably a shopbot
00:55 MrCurious of cource.. a router could translate a a template into an aluminum master quick and easy
00:58 OracleCarbon And a drill press, band saw, scroll saw, Dremel, and sheet metal brake
01:00 orlock hmm sheet metal brake
01:00 orlock thats something i'd like - not too expensive are they>
01:02 OracleCarbon I bought a crappy Harbor Freight benchtop one for $30, and the workshop I have access to has a $700 floor one
01:03 MrCurious i have the $30 harbor freight one
01:35 MrCurious HAHAHAHA ICBM is the name of our nuclear warheads, and also what you would say if you saw one coming .... I C B M's
02:21 rue_mohr2 aluminium or aluminum
02:23 rue_mohr2 I would like to point out a good source fro plastic sheets
02:24 rue_mohr2 http://ruemohr.org/~ircjunk/tutorials/mech/p1010110.jpg
02:24 rue_mohr2 cause you can get the raw material like wverywhere
09:17 rue_mohr2 Everyone suggest GMT times for happy hour
09:45 rue_mohr2 mine would be 23:00 GMT or so
09:45 rue_mohr2 no thats not right
09:45 rue_mohr2 heh
09:46 rue_mohr2 yea it is
09:46 iveevue Hello all o/
09:47 DagoRed .t GMT
09:48 DagoRed .t gmt
09:48 makepi Mon, 28 Jul 2014 14:29:59 GMT
16:06 deshipu so, I need to add a capacitor to smoothed the power consumption of the servos
16:06 deshipu the question is, how big should it be?
16:07 MrCurious GargantuaSauce: may be able to field that one...
16:32 GuShH deshipu: usually the cap is to supress noise
16:32 GuShH so it's a low value 10nF or so, depends on the frequency
16:44 MrCurious if your servo meets resistance, its going to pull crazy amps, and likely sag all other servos....
16:45 MrCurious could even sag the voltage to the cpu, causing a reset
16:56 Hyratel1 deshipu, what are you making?
17:08 Hyratel1 OracleCarbon, what weight class will your soaker bot be?
18:02 Hyratel1 MrCurious, thank you for the aliexpress suggestion
18:56 rue_mohr2 is it almost happy hour?
18:56 rue_mohr2 deshipu_, it should be 1000uF for every amp of ripple current
18:57 rue_mohr2 or 100uF per amp
18:58 rue_mohr2 no definitly 1000uF per amp
18:59 rue_mohr2 otherwise the cap will heat up, dry up, and blow up
18:59 rue_mohr2 its all up and up with capacitors
19:00 rue_mohr2 Delta is a company verry good at *just* undersizing capacitors
19:00 rue_mohr2 take for example all the xbox power supplies they made
19:11 rue_mohr2 .
19:11 rue_mohr2 we need a time to gather tommorow
19:45 Hyratel1 I need to figure out why this isn't properly reducing the peak output fed to the drive PWM
19:45 Hyratel1 http://pastebin.com/u3ViRWGi
20:18 Hyratel1 got it
20:18 rue_mohr2 I didn't lose the link, its supposed to be code
20:19 rue_mohr2 still dosnt' add up tho,
20:22 Hyratel1 no, i figured out what i was doing wrong
20:22 Hyratel1 it's just snippets
20:38 Nate_ Hi
20:38 Nate_ Could someone tell me if you can get a brushless motor to run both backwards and fowards using an ESC
20:42 Hyratel1 Nate_, if the ESC is able to yes
20:42 Hyratel1 that's a function of the ESC's sequencer
20:43 Nate_ alright thank you
20:44 Hyratel1 look for a "reverse" pin, or check the specs if it uses hobby servo
20:44 Hyratel1 signals
20:48 Nate_ k
20:54 Nate_ I'm not seeing anything like a reverse pin on this page
20:54 Nate_ could you help me?
20:54 Nate_ http://hobbyking.com/hobbyking/store/__2166__TURNIGY_Plush_60amp_Speed_Controller.html
20:55 rue_mohr2 yea you cant jst give up snippets, ther problem might be somewhere else
20:56 rue_mohr2 I'm not aware of any of the ESC's having a reverse
20:56 rue_mohr2 usually things fly up, or forward and ignore the rest of the options
20:57 rue_mohr2 if you found one that did do reverse, they would put the "stop" at the 1.5ms mark with 1ms being full in one direction and 2ms being full in the other
20:58 Nate_ english motherfucker do you speak it
20:58 Nate_ *,
20:58 Nate_ jk
20:59 rue_mohr2 ?
20:59 rue_mohr2 hmm my keyboard is eating vowels again
20:59 rue_mohr2 meh
21:06 robotustra hungry keyboard
21:08 Hyratel1 Nate_, yeah that's a prop driver
21:08 Hyratel1 you need a car motor driver to get reverse
21:09 Hyratel1 http://hobbyking.com/hobbyking/store/__14634__Turnigy_TrackStar_1_10th_Scale_60A_Car_ESC_Version_2.html
21:12 Hyratel1 Nate_, ^ see if that meets your needs
21:13 Tom_itx rue_mohr2, care to buy a vowel?
21:14 Tom_itx Nate_, cursing the help won't get you far
21:23 Hyratel1 Nate_,
21:23 robotustra http://imgur.com/gallery/jYX1N
22:03 MrCurious careful robotustra .... there are unethical 3d printer companies out there that copyright the work of others...
22:07 MrCurious *COUGH* http://traverseda.wordpress.com/2014/05/23/makerbot-blatently-steals-and-patents-a-community-design/
22:09 Tom_itx chinese will copy your ass if you stand still long enough
22:10 MrCurious thats different... thats outsourcing production to china for a minimal overhead
22:10 MrCurious the process is so streamlined as to seem automated these days...
22:10 MrCurious i call it predictive manufacturing
22:20 rue_mohr2 EH! can I buy an EH!!!
22:55 MrCurious rue_mohr2: what are you, the royal canadian kilted yaksmen?
22:58 rue_mohr2 kilt? dont be crazy
23:00 rue_mohr2 http://en.wikipedia.org/wiki/Layer_8#mediaviewer/File:OSI_user_layers.png
23:01 rue_mohr2 as you can see, the government keeps itself as far from the physical, informational layer as possable
23:38 MrCurious damnit. these universal joints are NOT the answer, unless they cacn swivel freely
23:42 rue_mohr2 aha, my machine has been up 95 days, that explains these open code windows
23:42 rue_mohr2 MrCurious, for the tripod?
23:43 rue_mohr2 MrCurious, why must they swivel?
23:43 rue_mohr2 having a hard time modeling that one in my head
23:43 rue_mohr2 usually people use ball joints dont they?
23:44 rue_mohr2 MrCurious, if the universal is connected by a threaded joint, it will twist a little on the thread :)
23:45 MrCurious thinking i need to find ball bearings, and use my rare earth magnets
23:45 rue_mohr2 dont go crazy, get it working
23:46 rue_mohr2 let it pivot on the thread
23:46 rue_mohr2 its about 15 degrees of less right?
23:46 MrCurious problem is that they arent pivoting on the thread on one end
23:46 rue_mohr2 changed topic of #robotics to: Arduino controlled, 3d printed psycho robots! | http://tom-itx.ddns01.com:81/~webpage/index.php | Join in at 2am GMT!
23:46 rue_mohr2 hu?
23:46 MrCurious tis a mock at me
23:47 MrCurious other end is really securly held into the bearing blocks
23:47 MrCurious TO EBAY!
23:51 MrCurious 10MM seems about right size
23:51 MrCurious and 100 pcs. because you never know when you are going to need a handful of 10mm ball bearings
23:58 rue_mohr2 well show us some picutres damnit
23:58 MrCurious just realized i have some of those magnetic molecule building kits...
23:58 MrCurious time to go hunting
23:58 rue_mohr2 ?