#robotics Logs

Dec 20 2015

00:14 Casper actually it is L6-20
00:15 Casper rue_house: mind you, the l5-20.... female is 16$, male is 24$
00:15 Casper I ideally need 3 pairs
00:32 rue_house been there, the best prices I found for stuff thats safe is home depot
00:35 Casper yeah...
00:35 Casper for metal bar, angle and rods... what's the cheapest place?
00:35 Casper (got a nice welder)
01:05 rue_house scrapper
01:06 rue_house usually you can buy stuff just slightly over scrap metal value
01:08 Casper for full length? or pieces?
01:10 rue_bed you dont want full length
01:11 rue_bed tend to be about 14-16'
01:11 rue_bed sometimes 20+
01:11 Casper ok, 8'
01:11 rue_bed maybe, you asked for cheap tho
01:24 Casper rue_bed: so scappers will only have left over and not good size... beside them, any 8' pieces that ain't homedepot priced?
01:42 Hyratel look fora Metal Supplier
01:43 Hyratel http://www.ptrailerusa.com/
01:43 Hyratel a place like this is where you would ask for suggestions
01:44 Hyratel we got a custom axle fabbed up for a trailer. weird size
01:45 Hyratel http://www.steelservicesinc.com/
01:50 Hyratel those are the kind of people you go to for a custom indtruial robot anchor platform
03:35 deshipu jhylands: nice! I wonder if the force sensor axis is correct
03:35 deshipu jhylands: perhaps you should have a force sensor that measures in any direction, not just in one
03:36 deshipu jhylands: then you could have the stumble reflex
03:38 deshipu jhylands: https://www.youtube.com/watch?v=_9H8EIs-hMc
03:39 deshipu it doesn't have to tell you the direction
07:04 jhylands deshipu, yeah, not sure - I'll experiment with it, see what happens
07:05 jhylands the foot is replaceable, so if it doesn't work I'll try something else
07:07 anonnumberanon Lots of bugs pissing me off this morning.
07:08 deshipu I finally removed the pyboard from my unfinished hexapod, and made it work with Tote
07:08 deshipu then I tried with WiPy, but no luck -- their Timer code is completely broken :(
07:10 deshipu I'm considering using wipy with a maestro servo controller, though -- hopefully their UART code works somewhat
07:16 veverak deshipu: any progress with raspi?
07:16 veverak :)
07:16 deshipu veverak: still waiting for the pcb
07:16 veverak I see
07:19 jhylands I'm going to use a Rpi 2 on the new robot, but I'm going to plug an Espruino Pico into one of the USB ports. The pico has been flashed with MicroPython
07:19 jhylands it will handle talking to the bioloid bus, and providing analog inputs
07:20 deshipu jhylands: why?
07:21 jhylands Why which part?
07:21 deshipu espruino
07:21 deshipu it's a very expensive alternative to a pro micro
07:21 jhylands because its tiny, and I don't need to mount another board or run wires to it or worry about powering it
07:21 jhylands I like python
07:21 jhylands and I already have one
07:22 jhylands so it doesn't cost me anything
07:23 jhylands pic - https://app.box.com/s/40b279knt71fgg741z6ui7n9krxg963e
07:24 deshipu hmm, I wonder if I designed an atmega32u4 board with that form factor...
07:24 deshipu would the China pick it up
07:24 jhylands you can probably buy one
07:24 deshipu well, I can buy a pro mini, but that has a microusb port
07:24 deshipu pro micro
07:24 deshipu sorry
07:25 deshipu so the plugs make it so much more bulky
07:26 jhylands sparkfun used to have something like that, but with a tiny - https://www.sparkfun.com/products/retired/9147
07:26 deshipu I could probably unsolder the usb port and solder an USB A plug in that place
07:26 deshipu jhylands: I have a bunch of digisparks, which are similar
07:26 deshipu http://digistump.com/products/1
07:27 deshipu even smaller
07:27 jhylands nice
07:27 deshipu but attiny lacks hardware uart
07:27 jhylands yeah, the pico has a ton of hardware ports available
07:27 jhylands 9 - 12 bit A/D lines
07:27 deshipu for that price I would expect so :P
07:28 deshipu jhylands: how is the hardware support of micropython on it?
07:28 deshipu jhylands: timers, uarts, i2c, etc?
07:28 jhylands its a cortex m4
07:28 jhylands as far as I know, its all working, but I'd have to ask my brother to be sure
07:29 deshipu I'll ask him when he appears on #micropython :)
07:29 deshipu shame this kind of information is not clearly documented somewhere
07:29 deshipu it could really make micropython more popular
07:30 SpeedEvil ESP32 could be interesting for robotic
07:30 SpeedEvil s
07:30 SpeedEvil Two cores, wifi, BT, more GPIO than ESP8266, 400K RAM
07:31 SpeedEvil Ethernet, but unfortunately only MII, not PHY
07:31 jhylands yeah, he's on the west coast, so it will be a few hours
07:31 jhylands damien did the port, so it probably all works
07:34 jhylands deshipu, https://github.com/micropython/micropython/wiki/Board-Espruino-Pico
07:34 jhylands and more generally, https://github.com/micropython/micropython/wiki/Boards-Summary
07:38 deshipu yeah, I know those, but they are not very detailed and often outdated
07:39 jhylands unfortunately, like most open source efforts on the internet, it requires people who want to keep it updated to keep it updated
07:41 deshipu I'd love to work on that
07:42 deshipu unfortunately, I have no way to get the information that I would need to update it
07:44 deshipu I think it's more of a cultural thing -- programming for other people, not just for yourself
07:44 deshipu for instance, I spent several days of work on updating the esp8266 micropython docs
07:45 deshipu and the next day, someone merged a patch that moved around half of the API without updating the docs
07:45 deshipu I thought I was going to cry
07:45 jhylands that sucks
07:46 SpeedEvil deshipu: :/
08:04 deshipu good news: the reversed servo works as expected
08:05 deshipu now I can have a simple gripper from two servos using the same signal
08:10 jhylands nice
08:22 veverak deshipu: awesome! :)
08:23 deshipu getting back to Logicoma
08:29 veverak AWESOME
08:29 veverak :D
08:30 veverak deshipu: thought about adding wheels to normal tote
08:30 veverak making it 4axis/leg
08:30 veverak but nah, that will need some more reasearch
08:31 veverak damn it
08:31 verak left tote in different city week
08:31 veverak but nah, christmas, will be time to play with it
08:32 veverak deshipu: btw: is logicoma documented somewhere online?
08:38 anonnumberanon I finally found my timing issue for the servo controller. If I unhook the radio module it starts working perfectly, the radio read must be interfering by interrupts into when I am trying to calculate my servo PWMs.
08:38 anonnumberanon scumbag library writers...
08:38 anonnumberanon or scumbag me for not knowing if there may be an example that lets you turn the radio on and off during each loop whenever you want
08:41 anonnumberanon Not gonna turn on the robot and let it wreck my desk like last time ! :) !
08:55 anonnumberanon startlistening(void), stoplistening(void)
08:55 anonnumberanon heck yeah
09:33 cereal_killa hi all, I'd like to experiment arduino with 1 accelerometer and 1 gyroscope using kalman filter. Somebody could help me ?
09:38 jhylands cereal_killa, that's a really complex thing - best bet is to ask google
09:38 jhylands there are groups out there who have done that
09:39 cereal_killa yep,complex... can you point me somewhere ? I asked google but found tons of incredibly complex formulas.
09:43 jhylands yeah, that's what is involved
09:43 jhylands tons of incredibly complex formulas
09:44 jhylands asking about how to do kalman filters for IMU is like asking "how do I design a chip"
09:44 jhylands if all you want is a working IMU, then I can point you at a product that already does that
09:45 jhylands but if you want to learn how to do it yourself, then I hope you're up for some pain
09:45 deshipu veverak: on hackaday.io
09:46 veverak good
09:46 cereal_killa I found on youtube a tutorial : "special topics - kalman filter ... but it's incomplete.
09:47 cereal_killa I decided to take this challenge and I don't give up
09:48 cereal_killa I know many people developed his KF out there and I want mine
09:49 deshipu what I find the most difficult with kalman filter is tuning
09:50 deshipu nobody tells you how to do it
09:50 jhylands from my understanding, its kind of like PID tuning
09:51 deshipu I finally found a paper that describes several methods and in summary admits that just randomly trying stuff until it works i the best way
09:51 jhylands like I said, just like PID tuning :-)
09:51 deshipu I need to learn pid too
09:52 jhylands I've spent more hours than I care to admit looking at kalman filters, but now that you can buy an IMU for very little $ that has it built in
09:52 jhylands I can't justify the time anymore
09:52 deshipu true
09:52 cereal_killa If you are interested try the youtube tutorial... for one sensor there is an easy example
09:52 verak never found proper material for karman filter with amtr
09:52 veverak I mean
09:52 veverak I was able to get the idea with single value
09:53 veverak but vectors? daaaamn
09:53 cereal_killa Could you tell me the IMU you used
09:53 jhylands This is the one I have now: https://www.tindie.com/products/onehorse/bno-055-9-axis-motion-sensor-with-hardware-sensor-fusion/
09:54 cereal_killa I abandoned the IMU with embedded KF because hw change often
09:54 jhylands or you can get it from adafruit: https://www.adafruit.com/products/2472
09:55 cereal_killa And I would replicate in the future what I use
09:55 jhylands this one includes a cortex m0 onboard that does the fusion
09:57 cereal_killa I searched the address you pointed me but no one use KF
09:58 cereal_killa I ordered BerryIMU ...not yet received
10:05 jhylands its using a filtering algorithm to produce a stabilized result
10:05 jhylands doesn't much matter what specific algorithm it uses
10:05 cereal_killa ok
10:26 deshipu often alpha+beta filtering is as good as kalman
10:26 deshipu and much easier to code
10:27 veverak hmm
10:27 veverak hmm
10:28 veverak it's nice to be far away from project you want to do
10:28 veverak you tend to optimalize things/processes you want to do with it when you are finally close :)
10:29 robotustra_ morning
10:38 deshipu veverak: it's also nice, because you do more thinking before you do thingsa
10:38 veverak yeah
10:39 deshipu veverak: having all your projects at arm's reach is demotivating
10:39 deshipu might explain why I always get the most done when I come back from vacations or other travel
10:39 veverak :D
10:39 jhylands deshipu, according to Dave, all the hardware capabilities are available on the pico with MicroPython
10:39 deshipu at least partially, because I think the fact that I'm rested has something to do with it too
10:40 deshipu jhylands: awesome! I already ordered some :)
10:40 deshipu gonna do science to them
10:50 anonnumberanon sounds naughty
10:56 anonnumberanon rue_mohr how long would it take to send 10 ints uart 1 avr to another?
10:56 veverak deshipu: also found nice way of battel-robots
10:56 veverak attach "air balloon" on rear side of the robot
10:56 veverak attach knife on the front side of the robot
10:57 anonnumberanon rue_house ^^
11:16 deshipu veverak: and how do you make them track each other?
11:16 veverak ehmm, remote control?
11:16 veverak :D
11:17 deshipu that's not really robots :(
11:18 deshipu you can do that with rc cars
11:18 veverak nope, they would suck with this
11:18 veverak they are not ment for this kind of movement
11:19 deshipu then rc tanks
11:19 veverak :)
11:20 deshipu but yeah
11:22 anonnumberanon human control is nice when the bot does most of the work
11:22 anonnumberanon 2 joysticks. 8 buttons
11:23 anonnumberanon im gonna inspire my fight move engine from a medieval combat game i like
11:25 anonnumberanon left joyatick to direction of walk and speed. right joystick to aim. triggers for different kicks and punch.
11:27 veverak exactly
11:28 veverak deshipu: logicma being able to actually use legs and wheels at same time would be great for this
11:29 deshipu veverak: I'm not sure
11:29 deshipu veverak: controlling it all at once might be a little hard
11:30 deshipu I will probably have some fun tuning the leg movements to be in sync with wheel movements
11:30 deshipu so you can move the legs back and forth while the wheels are spinning
11:30 deshipu not sure how well that will work
11:36 veverak hmm
11:36 veverak btw:
11:36 veverak deshipu: that continous rotation servos...
11:36 veverak it always spins 360 when you tell it ?
11:36 veverak 9
11:36 veverak (I mean you can't for example spin only 40)
11:42 deshipu veverak: it's basically a normal servo, with the pot disconnected from the shaft and set to the middle
11:43 veverak hmm
11:43 veverak so, as long as you send PWM signals, it spins?
11:43 veverak and the moment you stop, it stops ?
11:43 veverak cool
11:43 verak always thought it has to make one full t
11:46 anonnumberanon what degree u gettin veverak
11:48 veverak degree?
11:49 veverak WOW
11:49 veverak https://www.pololu.com/product/2130 cool
11:54 anonnumberanon yeah, college degree
11:55 robotustra_ veverak: it's wow already like 3-5 years
11:56 veverak anonnumberanon: applied informatics
11:56 veverak or that's what it is called
11:56 veverak robotustra_: O:)
11:59 anonnumberanon what does it correspond to in american college degrees?
12:00 veverak duuno, don't care about american
12:00 veverak ehmm
12:00 veverak bachelor program!
12:00 veverak yeah :)
12:05 anonnumberanon in what field lol? man i dont think you will be able to finish ur degre...
12:11 veverak "applied informatics" ?
12:11 veverak and why not? :)
12:19 anonnumberanon i just looked it up in wikipedia
12:22 deshipu veverak: if you send 1500µs, it stops
12:22 veverak hmm
12:22 veverak yeah!
12:22 deshipu veverak: if you send anything else, it spins the faster the farther it is from the middle
12:22 veverak I see
12:22 veverak deshipu: nice
12:23 deshipu it's convenient for simple "turtle" robots
12:23 deshipu as you don't need a separate motor driver
12:23 veverak well, the ones from pololu I linked seems small enough
12:23 deshipu just slap together two servos, wheels, battery and some uc
12:23 veverak yeah
12:24 deshipu I was thinking about removing one stage from their gear boxes though
12:24 jhylands veverak, if you use a motor driver like the pololu one, you can gut the servo (take out all the electronics), and control the motor directly
12:24 deshipu removing one gear and gluing two gears together
12:24 veverak jhylands: exactly!
12:24 veverak :)
12:24 deshipu to make them faster
12:24 veverak jhylands: I also thought about adding encoder to be honest
12:25 veverak but that would require some research
12:25 deshipu or I could just up the PWM frequency
12:25 veverak deshipu: or put there bigger wheels
12:25 veverak :)
12:25 deshipu veverak: why fix something in hardware if you can fix it in software? ;)
12:25 jhylands if you want encoders, I would recommend skipping servos entirely, and get the little Pololu gearmotors with the built-in quad encoders
12:25 veverak deshipu: true
12:25 deshipu jhylands: link?
12:26 veverak jhylands: exactly what I just found :D
12:26 deshipu veverak: link?
12:26 shipu is lazy t
12:26 jhylands https://www.pololu.com/category/141/micro-metal-gearmotors-with-extended-motor-shafts
12:26 jhylands https://www.pololu.com/product/3081
12:27 jhylands or https://www.pololu.com/product/3081
12:27 deshipu the pololu prices never stop to amaze me
12:27 deshipu when I compare them with aliexpress...
12:27 jhylands sorry, or https://www.pololu.com/product/2591
12:27 deshipu I know the quality control etc. but still
12:30 deshipu I need to seriously start playing with hall effect sensors
12:30 deshipu the stuff people do with them is amazing
12:31 veverak :)
12:31 veverak well
12:31 veverak it seems like continous rotation servo is best pic for start anyway
12:32 jhylands its certainly the simplest
12:33 jhylands The AX-12 can be converted from servo mode to motor mode with a software switch
12:35 veverak nope, too expensive to even consider
12:35 veverak :D
12:37 veverak also, too big
12:37 veverak :)
12:39 deshipu also, too power-hungry
12:39 deshipu sour grapes
12:40 veverak http://www.trossenrobotics.com/dynamixel-xl-320-robot-actuator much better
12:41 anonnumberanon out of stock
12:41 anonnumberanon maybe cause christmas
12:43 jhylands http://www.robotshop.com/ca/en/dynamixel-xl-320-ollo-smart-serial-servo.html
12:43 jhylands in stock
12:46 jhylands or the US version - http://www.robotshop.com/en/dynamixel-xl-320-ollo-smart-serial-servo.html
13:02 deshipu with adcanced functions!!!
13:02 veverak :D
13:02 deshipu advanced
13:03 veverak again
13:03 veverak first guy to put "smart" controller into those cheap 9g servos
13:03 veverak will get rich
13:03 veverak :)
13:05 deshipu meh
13:05 deshipu veverak: I got the h-bridge to work for that, and ordered the pcb
13:06 veverak :)
13:09 veverak deshipu: but you have to mod each servo...
13:14 deshipu just replace the pcb
13:22 rue_bed you guys remaking the openservo project?
13:24 deshipu well, not exactly
13:24 deshipu it's a little bit lower quality
13:28 rue_bed which avr did openservo use?
13:34 deshipu rue_bed: I think they had several approaches
13:36 deshipu rue_bed: hard to say, actually, their website sucks
13:36 deshipu and I say that as MoinMoin developer
13:37 deshipu 3.0 uses ATmega168 it seems
15:54 rue_shop3 armyofevilrobots, you up?
15:54 rue_shop3 armyofevilrobots, would it be a bad thing if I dropped off some sheets of mdf to cut up later?
17:40 Casper yay got twistlock connectors! need a receptacle, a box and the wire...
17:42 deshipu what does it do?
17:46 Casper will be for my welder
17:48 Casper my unit is a 120/230V, I'm at it's limit with 120V, so I need to boost the power... I have then a few choices, one is to get a real welder outlet, but then I need an extension anyway... or I make the extension and use the "native" connector of the welder: twistlock input. It's cheaper to go that route
17:49 Casper and if I need the other plugs, then I can reuse the extension and use the cables that came with the unit (they provide a twistlock to "standard 120V" and a second twistlock to welder plug)
17:50 deshipu 120V? where are you?
17:50 deshipu that kind of voltage in the outlet must really suck
17:51 Casper 120V is fine for almost everything
17:52 Casper ... except high power stuff, where 240V is available
17:53 deshipu and except water kettles
17:54 veverak fu
17:54 veverak ROS won't compile
17:54 veverak but this time on different package
17:55 deshipu fu too
17:59 veverak many warnings during compilation
18:03 deshipu well, warnings are normal with software written to work, not to look nice ;)
18:07 veverak [ 56%] Linking CXX executable ../../devel/lib/rviz/rviz
18:07 veverak ../../devel/lib/librviz.so: undefined reference to `YAML::Emitter::Write(std::string const&)'
18:13 Casper deshipu: not that bad, still 1500W, so it don't take too much time
19:33 robotustra_ https://www.youtube.com/watch?v=tmxW3q6usYM
19:38 Jak_o_Shadows I personally think you need to model more of the ligaments & tendons in a walking robot
19:38 Jak_o_Shadows Put some springs in there to give some energy return or something
19:38 Jak_o_Shadows That said, all of those are impressive
19:41 SpeedEvil https://www.youtube.com/watch?v=pgaEE27nsQw
19:41 SpeedEvil Jak_o_Shadows:
19:42 Jak_o_Shadows The only problem with that one is that it needs linear actuators that dont' suck?
19:42 Jak_o_Shadows So you're looking at pneumatics?
19:57 Snert I've seen some small linear actuators - anyone ever tried one?
19:57 Snert 2" stroke.
20:03 Hyratel dont' think so. what're you looking into them for?
20:08 Snert An extensible forearm.
20:08 Snert dunno zactly what that would be called.
20:09 Hyratel telescopic
20:09 Snert one of my bog things is aesthetics.
20:09 Snert big
20:10 Snert what the arm looks like in the stowed position is important.
20:10 Snert and being able to collapse and extend 1 if not 2 sections makes it more compact.
20:11 Hyratel you'll need to make sure the torque and flexiion won't damage the actuator
20:11 Hyratel and if it can't be assured, you'll need to augment it with sliders of some sort
20:11 Snert yes. I'm getting that visualized.
20:14 Snert my mockup board might just have the extensor mounted flat on the board or something.
20:14 Snert to get the bearings/slider part worked out.
20:17 akem hey
20:22 Jak_o_Shadows I dunno, isn't the thing that linear actuators normally have pretty low speed limits
20:23 Hyratel Jak_o_Shadows, yes they do
20:24 Hyratel a lead screw has a very high ratio and high rotary inertia in the drive train
20:26 Snert not as heavy as that...more like this.....
20:26 Snert https://www.pololu.com/product/2345
20:27 Hyratel you'll need external feedback loop sensor
20:27 Snert of course. they do have that model with an encoder.
20:28 Snert but it's only quad :(
20:28 Hyratel you need a slide pot or a winch pot
20:28 Snert I'm after absolute.
20:28 Hyratel you could zero every startup
20:28 Snert winch pot...intresting. I'll keep that in mind.
20:29 Hyratel descriptive, not sales name
20:29 Snert a 4" strip of linear gray code .... say 1" wide is my idea.
20:29 Snert I can build the detector no problem.
20:29 Hyratel you can get optogate strips
20:30 Hyratel there was one in my old printer
20:30 Snert yes, but that wasn't gray.
20:30 Hyratel the main reson for using them is to allow for closed loop speed control on a brushed motor
20:30 Hyratel OR making the action RPM-independent, and tied to the position
20:31 Hyratel so that it doens't have to worry about the exact RPM, just gating the actions of the print head to sync with the velocity
20:31 Snert see, all my stuff will be low speed.
20:31 Hyratel http://www.andymark.com/product-p/am-2674.htm
20:32 Hyratel non-kinetic motion?
20:33 Snert no, its just an arm doesn't move around all that fast.
20:33 Snert it can take 3 or 4 seconds for the extensor to move when it needs to.
20:34 Hyratel i mean more, do you come to a stop at the end of each motion to wait for oscillations to damp out, before starting another movement
20:34 Snert i see...yeah there will be much to consider.
20:36 Snert I've heard of motion profiles but haven't looked into it yet.
20:36 Snert when I have something that moves on a test board I'll get to it.
20:38 Snert I know you need to brake the steppers and decelerate/accel the motors and stuff. but haven't looked at it quite yet.
22:16 armyofevilrobots rue_shop3: I have a ton of stuff going on in the garage right now. Could we delay til later this week?
23:32 rue_bed armyofevilrobots, np