#garfield Logs

Sep 25 2022

12:12 AM rue_shop3: 1800 lines/rev
01:26 AM rue_shop3: steps on rising edge
02:19 AM rue_mohr: oh WOW
02:19 AM rue_mohr: the ring in a stepper motor shaft happens not AROUND the target position, but BEFORE IT!
02:19 AM rue_mohr: that blows my mind.
02:23 AM rue_mohr: the ramifications of that are crazy
01:50 PM rue_mohr: 2810
01:50 PM rue_mohr: huh
04:13 PM rue_mohr: polprog, is the serial programmer bidirectional then?
04:13 PM rue_mohr: just tx?
05:07 PM rue_mohr: Tom_L, thought, the machine can only sustain that top speed for a second maybe, at full speed it only takes 3 seconds to traverse the 8' table, and there has to be time for ramp-up and ramp-down
05:20 PM Tom_L: sounds a bit crazy
05:40 PM rue_mohr: well, I hate waiting for machines to jog
05:40 PM rue_mohr: the old old cnc jogs at a top speed of ~1"/min
05:41 PM rue_mohr: PER MINUTE
05:41 PM rue_mohr: top speed
05:41 PM rue_mohr: their just 4 phase unipolar drivers
05:41 PM rue_mohr: so, any faster and they lose too much torque to turn
05:44 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/temp.png
05:44 PM rue_mohr: I had a bit of a time designing that with the tapers for casting
05:49 PM Tom_L: should have said something.. draft angles are easy in catia
05:50 PM rue_mohr: hah oh dear
05:50 PM rue_mohr: so, for 100:1 I recon I got to make my own pullies
05:51 PM rue_mohr: I'll try it, but if they burn out, its not really a big surprise
05:52 PM Tom_L: ever mess with python configparser?
05:52 PM rue_mohr: no...
05:52 PM rue_mohr: what kinda config files?
05:52 PM Tom_L: for linuxcnc
05:53 PM Tom_L: for a config utility
05:53 PM rue_mohr: it implies there is a type of config file it parses
05:53 PM rue_mohr: which implies a particular syntax
05:53 PM Tom_L: https://thepipelineweb.wordpress.com/2017/05/16/python-save-comments-from-configparser/
05:53 PM rue_mohr: almost everyone uses xml now..
05:54 PM Tom_L: trying to get comments saved but the parser doesn't like to do it as it's supposed to
05:54 PM Tom_L: that was one solution i found but it has troble with multiple blank lines
05:58 PM rue_mohr: wow
05:58 PM rue_mohr: primative!
05:58 PM rue_mohr: iaiaia
05:59 PM rue_mohr: here is a video of a stepper motor doing x4 microstepping, the purple is the target, the red is the actual motor shaft
05:59 PM rue_mohr: https://twitter.com/RueNahcMohr/status/1574170629368320000
06:00 PM Tom_L: i saw it i think
06:00 PM rue_mohr: heh just put it up
06:00 PM rue_mohr: see the delay, miss, and ring?
06:01 PM rue_mohr: :S
06:01 PM rue_mohr: 10000fps
06:01 PM Tom_L: oh i saw the other one then
06:01 PM rue_mohr: yep, been going a bit crazy
06:01 PM rue_mohr: this is quite interesting
06:01 PM rue_mohr: the encoder is good to 0.05 degrees
06:21 PM rue_mohr: ok, the pulley is printing, the stepper analysis is prettymuch good
06:21 PM rue_mohr: I'v learned things I didn't know I didn't know
06:22 PM rue_mohr: oh right the bungees for the exosuit
06:22 PM rue_mohr: and the injection molder
06:23 PM rue_shop3: and stripping down that printer
06:23 PM rue_shop3: I just have to walk around and it all becomes clear
06:25 PM rue_shop3: I get 200% from the tike tires
06:25 PM rue_shop3: so max len I need is 34cm
06:26 PM rue_shop3: so the bungee should be 17cm
06:26 PM Tom_L: somebody should try to get ops for robotics in case they are needed some day
06:27 PM Tom_L: i'm not going to persue it
06:45 PM rue_mohr: its in administrative lockdown
06:45 PM rue_mohr: they wont allow it cause the name is wrong
06:46 PM rue_mohr: and they dont want to get involved in the dispute
06:46 PM rue_mohr: which there isn't really
08:10 PM rue_shop3: whats got a 100:1 gearbox?
08:10 PM rue_shop3: thats well into the area of worm drive isn't it?
08:11 PM rue_shop3: I have a photocopier gearbox at 55:1
08:22 PM rue_shop3: which is apparently atypical, normal seem to be around 20:1
08:40 PM rue_shop3: rotissory motor thats 500:1
08:40 PM rue_shop3: ok 55:1 with 2:1 ok
09:06 PM Tom_L: my rotary is 40:1
09:07 PM rue_mohr: I dont want to burden the DC motors with the same step size requirement as the steppers do
09:07 PM rue_mohr: I'm targeting 5 degrees
09:07 PM rue_mohr: some of the motors I'm probably using dont have many poles