#robotics Logs

Mar 29 2017

01:13 AM goppo: i'm trying to join two 3mm rods together to make a T configuration. does any one know if there're adapters out there for this?
04:38 AM deshipu: what are the rods made of? what do you want the connector to be made of?
04:39 AM deshipu: how strong and rigid does it have to be?
05:49 AM pokmo: are there ways to make a 120 deg servo turn a shaft by 180 degs without using gears?
05:49 AM pokmo: how about linkages?
05:56 AM Jak_o_Shadows: You could use pulleys
05:56 AM Jak_o_Shadows: Little simpler than gears
05:56 AM Jak_o_Shadows: Probably simpler than linkages
05:58 AM pokmo: if linkages, how should one go about it?
05:59 AM Jak_o_Shadows: Youtube? Mecanno?
05:59 AM Jak_o_Shadows: Meccano?
06:00 AM pokmo: i can't seem to find any example
06:00 AM pokmo: would it be some sort of crank?
06:01 AM Jak_o_Shadows: It'd be more than a 4 bare linkage. At the least.
06:01 AM mun: so many?
06:02 AM Jak_o_Shadows: Remember the vector between the two fixed points counts as a link.
06:02 AM Jak_o_Shadows: With a 4 bar I think you just unavoidable get a singularity if yu're looking at oing what you want
06:04 AM pokmo: true
06:04 AM pokmo: maybe gears would be easier
06:05 AM mun: you'll have to make sure the gears properly mesh
06:05 AM mun: that's not so straightforward
07:39 AM pokmo: gears like these are meant to be tight fit to the shaft. but how they meant to be fitted?
07:39 AM pokmo: just with brute force?
07:43 AM SpeedEvil: Gears are typically either pressed on, have a key, an assymetric shaft and gear, or grub screws to hold them on
07:47 AM veverak: or cold/hot trick
07:57 AM robotustra: veverak: did you finish your software?
09:01 AM rue_bed: you didn't see my trick
09:19 AM robotustra: rue_bed: are you talking to me?
09:20 AM robotustra: https://www.youtube.com/watch?v=0ZBD2tcKOU4
09:37 AM robopal: it cant really walk, can it?
09:37 AM robopal: it "walks"
09:46 AM goppo: are there standards for threading a hole in plastic? say the hole is 2mm dia, how big should the screw be?
09:51 AM robopal: self threading screw?
09:52 AM veverak: robotustra: still a lot of work to do
10:04 AM robotustra: goppo: I think for hard plastic one can apply the same standards as for metal, but for soft plastic - I think there is no
10:04 AM goppo: robopal, yeah
10:04 AM robotustra: you have to take into account the stiffness
10:05 AM goppo: is nylon considered soft plastic?
10:05 AM goppo: well, POM
10:06 AM robotustra: nylon is rigid, yes
10:07 AM goppo: could M2.4 screws do?
10:07 AM robotustra: yes, why not
10:07 AM robopal: do you have some scrap to try?
10:07 AM robotustra: drill 1.8 mm and tap
10:07 AM goppo: i just don't know if 0.2mm is deep enough
10:08 AM goppo: well, the holes are already there. 2mm dia
10:08 AM goppo: throughholes
10:08 AM robotustra: what is the thikness?
10:08 AM goppo: robopal, well i've only got one
10:09 AM goppo: robopal, it's 1.5mm thick
10:09 AM goppo: robotustra, ^
10:09 AM robotustra: I would sharpen the bolt and screw it without threading
10:09 AM robotustra: tip of the bolt
10:10 AM robotustra: should work
10:10 AM goppo: robotustra, how about self tapping screws?
10:10 AM robotustra: you can grease it a little bit
10:10 AM robotustra: they have bigger thread step
10:11 AM robotustra: for 1.5 mm better to use smaller step
10:11 AM goppo: oh right
10:11 AM robotustra: usual small bolt should work
10:11 AM goppo: but can bolts create threads in the hole?
10:12 AM goppo: since the steps are so small
10:12 AM robotustra: yes
10:12 AM robotustra: it will
10:12 AM robotustra: don't warry, atoms is much smaller
10:12 AM goppo: lol
10:12 AM robotustra: are*
10:12 AM goppo: so M2.4 bolts?
10:13 AM robotustra: yes
10:13 AM robotustra: good enouph
10:14 AM goppo: robotustra, but then why not M2.4 screws?
10:14 AM goppo: not self-tapping
10:14 AM goppo: *non
09:26 PM robotustra: piu piu
09:43 PM robotustra: funny https://www.youtube.com/watch?v=WyKVOVVW97o