#robotics Logs

Jul 08 2015

00:04 wolfmanjm miles :)
00:05 wolfmanjm I've done a bridge test over about 50mm I think
00:05 wolfmanjm but it took a while to tune it
00:05 wolfmanjm needs a lot of cooling and tweak the flow rate and speed
00:05 wolfmanjm small bridges should be fine
00:22 rue_shop3 it came out great, but I'm slightly overextruding
00:30 Hyratel1 rue_shop3, pics?
00:39 rue_house reprinting :)
00:39 rue_house trace is a bit fat
01:04 rue_shop3 oo I need to recalibrate!
01:04 rue_shop3 I should be 1.5 and I'm 1.8
01:06 Jak_o_Shadows ok, so that laptop is out as the octoprint server, as it is not working.
01:12 Jak_o_Shadows also, this is one print that's staying on cause of stickytape
01:15 rue_house http://www.thingiverse.com/thing:915949
01:15 Jak_o_Shadows Nice.
01:15 Jak_o_Shadows Is that ABS or PLA?
01:15 rue_house PLA
01:15 rue_house heated bed isn't attached yet
01:15 Jak_o_Shadows Mmm, thought so, ABS colours seem to be more saturated.
01:16 rue_house yea, I was really dissapointed with the washout blue
01:19 Jak_o_Shadows Apart from being easier to print, is there any advantages to PLA?
01:21 rue_house none that I'm aware of
01:22 rue_house rifraf only did ABS and had great results
02:00 Jak_o_Shadows little bit of persuasion and it may work !
02:04 Jak_o_Shadows http://jak-o-shadows.github.io/picturedump/3dp/upperv2.jpg damn the photo makes it look bad.
02:12 rue_house ugh
02:12 rue_house is that pla?
02:12 rue_house its sticking in the nozzel
02:12 rue_house if its pla, wipe some of the filament with crisco
02:12 rue_house check your cooling
02:13 rue_house and I told you to dial up your multiplier and make your layers thinner
02:13 rue_house looks like your .5mm layers there
02:14 rue_house if you have a .5 head, you should not use layers more than .4mm, I cant push mne much past 0.35
02:16 Jak_o_Shadows That would be ABS, it does stick to the nozzle sometimes, I put the default extrusion width to 106%, but I made layers 0.3mm. It's a 0.4mm nozzle
02:17 rue_house well the numbers are still out
02:17 rue_house thats why you have cracks across the side of your prints
02:17 rue_house http://www.thingiverse.com/thing:915949
02:17 rue_house I put a picture on the page
02:17 rue_house your sides should look like that
02:18 rue_house your layers should be MAX 0.32 with a 0.4mm nozzel
02:18 rue_house I suggest 0.3 max
02:19 rue_house 0.25 is what you should be
02:21 Jak_o_Shadows Yeah, so my sides don't really look like that.
02:21 rue_house thats not your pic?
02:22 Jak_o_Shadows no, they don't look like yours
02:22 Jak_o_Shadows sorry
02:22 rue_house smoother?
02:23 Jak_o_Shadows Yes, that is my photo.
02:23 rue_house recent or really old?
02:23 Jak_o_Shadows very recernt
02:23 rue_house the multipler and layer height are out in that photo
02:24 rue_house whatever, gnight
02:24 Jak_o_Shadows night
08:56 solifugus Does anyone know of a linear actuator that is low cost and strong but doesn't require a lot of travel or speed. Electric on/off, not a stepper.. I want to control with a simple relay.
09:01 Tom_itx solonoids are cheap
09:02 solifugus I'd like to avoid the expense and complication of a bundle of stepper controllers... just time how long the actuator is moving using a relay, on/off.
09:03 rue_house solifugus, yes
09:04 rue_house swisted line actuator
09:04 rue_house twisted line
09:13 solifugus I will google that..thanks
09:27 rue_house http://hackaday.com/2015/01/17/twisted-string-actuators/
09:27 rue_house solifugus, ^
09:33 SpeedEvil solifugus: Stepper controllers are very cheap
09:34 solifugus SpeedEvil, I need to drive about 30...
09:34 solifugus I wish there was a single controller for a large number of steppers.. I cannot seem to find one on the Internet.
09:34 solifugus Maybe this? http://www.arcus-technology.com/products/multi-axis-motion-controller/4-axis-usb-controller/
09:35 solifugus I am really a software developer though.. my knowledge of electronics is, unfortunately limited... I am not even sure what 4-axis means..
09:36 solifugus I am hoping to use my raspberri pie for this.. hence, the usb control of that stepper driver might be ideal.
09:36 SpeedEvil http://www.ebay.co.uk/itm/5x-A4988-Stepstick-Stepper-Motor-Driver-Module-Heat-Sink-3D-Printer-Reprap-HUS-/351404456569?pt=LH_DefaultDomain_3&hash=item51d1567a79 - for example
09:36 SpeedEvil These just have step and direction inputs you could power from the Pi
09:36 SpeedEvil s/power/control/
09:37 SpeedEvil https://www.pololu.com/product/1182
09:38 SpeedEvil In principle, you only need one wire per motor, and a shared direction input
09:38 SpeedEvil s/wire/GPIO
09:39 SpeedEvil Time moving only relies on friction being constant, as well as all motors and loads being well matched
09:41 solifugus yes well, driving a stepper motor with a threaded rod will make a great linear actuator.. I have one of those... experimenting.
09:42 solifugus Those are cheap and small.. so about $180 for all 30. lots of wiring, though.. I am curious how you drive a stepper two directions with only one wire.
09:43 solifugus I wonder if I could just pay an electrical engineering student to build a controller board for me.. each motor with one pin for each direction..
09:44 solifugus So I can focus on software.. which is my competence..
09:46 solifugus My brother is helping with the mechanical parts.. FreeCAD, 3D printing in ABS plastic to make two-part silicon molds for final parts in PVC...
09:46 solifugus Our last humanoid two years ago wore out too quickly... abrasive joints. PVC will prevent that.... and its cheaper.
09:48 solifugus pvc lasts longer against abrasion that alumninum by a long shot.. and this way is cheaper and simpler than using separate bearings.
09:52 rue_house if your just a programming guy, why do you care how many wires there are?
09:52 rue_house and how much money are you spending on this project?
09:52 rue_house $5/ axis?
09:53 rue_house more? less?
09:53 rue_house steppers are about $40/axis by the time you have drivers in
11:32 SpeedEvil solifugus: you have a shared direction wire, and one step wire per stepper.
11:34 SpeedEvil solifugus: Every time you want to move the steppers, you pull the direction line to all the drivers low, and then then pulse the step lines of the ones you want to go clockwise, and repeat for anticlockwise with the direction line high
14:40 robotustra hi
15:36 deshipu yawn
15:36 robotustra any news?
15:36 deshipu https://www.youtube.com/watch?v=WvPRhwA7Aa0 <-- Wheels \o/
15:36 deshipu https://www.youtube.com/watch?v=2LjSKvdbtPk <-- Legs \o/
15:37 robotustra https://www.youtube.com/watch?v=om_hhY21Tbg&feature=youtu.be eyes
15:38 robotustra is it wheels?
15:39 robotustra these are WHEELS http://i.imgur.com/E8TCWqW.jpg
15:40 deshipu robotustra: are you actually getting stereo vision from that?
15:48 wolfmanjm deshipu: cool, not put the wheels on another servo so you can make the wheels directional :)
15:48 wolfmanjm *now
15:48 deshipu wolfmanjm: nah, no need
15:48 deshipu wolfmanjm: they are angled, so moving the leg forward and backward turns it
15:50 wolfmanjm nice idea
15:51 robotustra deshipu: I will
15:51 deshipu I will have to test it more, of course
15:51 deshipu robotustra: what are you using for processing the image?
15:51 robotustra not yet. I'm getting 17 fps
15:52 robotustra my own filters
15:52 robotustra I get raw snapshots
15:52 deshipu how do you find the common points between the two images?
15:53 robotustra merging algorythm
15:55 robotustra there are plenty of common points, it depends on the where eyes are focused on
15:57 agile_prg2 anyone familiar with the canopen protocol?
15:57 robotustra you mean CAN?
15:59 agile_prg2 ya
15:59 robotustra I know usual CAN
15:59 robotustra not open one
16:00 agile_prg2 oh ok
16:10 robotustra deshipu: do you do binocular vision yourself?
16:18 deshipu robotustra: no, I didn't even start with vision yet
16:18 deshipu robotustra: just distance sensors
16:25 robotustra garganaut souse is in here?
16:26 blib what motor controller can I buy for 20A stall current motors at 12v - times 4?
16:26 blib The ones I'm looking at are expensive > $100
16:27 robotustra why can't you use 24 V by 10A current?
16:27 blib robotustra: what happens when the motor stalls? the controller smokes?
16:30 robotustra or motor
16:30 robotustra it depends
16:31 robotustra usually ppl do a current protection
16:31 robotustra against this