#garfield Logs

Feb 22 2020

01:34 AM polprog: rue_mohr: the fpga
01:39 AM polprog: sorry, i was half asleep
01:42 AM rue_mohr: are you moreor less asleep now?
01:52 AM X704 is now known as tiwake
03:12 AM Tom_L: less
03:15 AM rue_mohr: ok, so I did an almost-86 turn transformer
03:15 AM rue_mohr: some of the wire didn't fit
03:15 AM rue_mohr: I need to go to #37-ish
03:16 AM rue_mohr: 1am, I'm beat tho
03:16 AM rue_mohr: and I need food
03:38 AM polprog: 86 turns? no wonder mine are shit.. i need to get the enamel wire from the basement then
03:38 AM polprog: and some bobbins
03:38 AM rue_shop1: :)
03:39 AM rue_shop1: if your freq is high enough your ok
03:39 AM rue_shop1: I'm shooting for 40Khz, which is moderatly low
03:39 AM polprog: i was trying at various up to 150 odd khz
03:40 AM rue_shop1: k,
03:40 AM rue_shop1: low turn count inductors can be from 250kHz upwards of 1MHz
03:42 AM rue_mohr: at 500kHz things start going crazy
03:42 AM rue_mohr: by 1Mhz, your hard pressed to find fast enough diodes
03:42 AM rue_mohr: and fet drivers throw crazy amounts of power
03:42 AM polprog: youre right, i was to check a different diode
03:43 AM rue_mohr: computer supplies (older ones) are about 40kHz
03:44 AM rue_mohr: those small dc-dc you get from china are 250k-300k
03:44 AM rue_mohr: easier for them to get away with it as its all in one chip
03:50 AM polprog: i have a tiny bobbin so next time im in the basement ill just grab the wire spools
03:50 AM polprog: replaced toner cartridge in the printer and now i can photocopy pencil schematics
03:51 AM polprog: good, at least one of the things done...
03:57 AM rue_mohr: :)
04:03 AM polprog: weird, this transformer has 5 pins on one side, theres wire going to it but no connection to any of the 4 others
04:03 AM polprog: one winding is .30 ohm, another 4.20 ohm
04:03 AM polprog: this will be useful
04:03 AM polprog: bbl
04:04 AM rue_mohr: sometimes they leave extra pins as mounts
05:14 AM X704 is now known as tiwake
05:37 AM polprog: but there is a wire soldered to it
06:06 AM X704 is now known as tiwake
12:59 PM rue_bed: how many pins have wires?
04:44 PM Tom_L: awfully quiet here
06:19 PM rue_mohr: visitors
06:19 PM rue_mohr: so, my idea for using 74xx04 to delay a 25/50 mhz signal so that a flipflop can demodulate it works!
06:20 PM rue_mohr: 4 74hc04 gates give me 18ns delay
06:21 PM rue_mohr: the input signal, and the 18ns delayed signal, fed into the clk/data lines of a 74hc74 flip-flop give me 1 and 0 depending on the input freq
06:24 PM rue_mohr: http://ruemohr.org/~ircjunk/circuits/25-50MhzModDemod.jpg
06:24 PM rue_mohr: http://ruemohr.org/~ircjunk/circuits/25-50MhzModDemod2.jpg
06:26 PM rue_mohr: the purple wire is the switch for modulating
06:26 PM rue_mohr: point being, can subst that line with an ethernet transformer
06:26 PM rue_mohr: to isolate the signal
06:43 PM rue_mohr: maybe today I can sit down and play with the encoder for the fpga
06:44 PM rue_mohr: it would be nice to make a shift register communication thing too
06:45 PM rue_mohr: make a shifted serial interface to the 7 segments or something :)
06:46 PM rue_mohr: gonna rest
06:47 PM rue_mohr: its 4:40 now, I need to hit the store before 9
06:47 PM rue_mohr: I want to find some wire to do those transformers
06:47 PM rue_mohr: if I can get a transformer going, I can build up a motor driver and test it out
06:49 PM rue_mohr: I should make a power module for the driver too
06:50 PM rue_mohr: had an idea on that
06:50 PM rue_mohr: zhanx, you working on anything?
07:22 PM Tom_L: rs232 to parallel?
07:23 PM Tom_L: or just an 8bit shift to parallel
07:53 PM rue_mohr: naw, just clock/data/strobe
07:54 PM rue_mohr: need to get up an go shopping I suppose
07:54 PM rue_mohr: positivly undermotivated
08:21 PM Tom_L: i fired the mill up for a bit
08:21 PM Tom_L: that's about all
09:46 PM rue_mohr: how did the program run?
09:53 PM rue_mohr: ok , got the groceries put away
09:53 PM rue_mohr: wire
09:53 PM rue_mohr: I need wire...
10:12 PM Tom_L: ran ok but needs to be a bit deeper
10:12 PM Tom_L: i used a v bit and they didn't have those at the vo'tech
10:12 PM Tom_L: pretty neat for completely hand written
10:16 PM rue_shop1: found some .15mm, which is close
10:16 PM rue_shop1: :)
10:16 PM rue_shop1: just got a length for what I need here
10:17 PM Tom_L: i might take a pic of it in a bit
10:17 PM rue_shop1: 9 feet
10:26 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/cnc/xtra/bunny.jpg
10:27 PM Tom_L: it was an exercise
10:27 PM rue_shop1: I got my coil
10:27 PM rue_shop1: hah, cool
10:27 PM rue_shop1: thats a lot to work out by hand
10:28 PM Tom_L: he said it took about 30 min
10:28 PM Tom_L: i think they gave point coordinates but i'm not sure
10:30 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1150286.jpg
10:30 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1150287.jpg
10:31 PM rue_shop1: so, the L293 has a bug
10:31 PM Tom_L: is that a HF calipers?
10:31 PM Tom_L: have one exactly like that but inch
10:31 PM rue_shop1: heh, these are ones I bought from the local shop, they turned out to be the best
10:31 PM rue_shop1: the other are from china, and are an issue
10:32 PM Tom_L: HF sells those
10:32 PM rue_shop1: this one has the serial port
10:32 PM Tom_L: they were cheap enough i got an 8"
10:32 PM Tom_L: no port that i see here
10:33 PM rue_shop1: the top thing slides
10:33 PM rue_shop1: beside the lock screw
10:33 PM Tom_L: so did you wind that?
10:33 PM rue_shop1: there is a little arrow
10:33 PM rue_shop1: yea
10:33 PM rue_shop1: thats on the coil winder
10:33 PM rue_shop1: nice to know it'll stop for ya
10:34 PM Tom_L: mine has a triangle on the top but i think those are just screw holes
10:35 PM rue_shop1: push in the direction of the triangle
10:36 PM rue_shop1: :)
10:36 PM Tom_L: no, it's one piece
10:36 PM Tom_L: oh hell, how about that!
10:37 PM rue_shop1: yea, those 4 pins
10:37 PM Tom_L: 2 thruholes with solder pads
10:37 PM rue_shop1: serial port
10:37 PM rue_shop1: er, hmm
10:37 PM Tom_L: yeah i see 4 fingers now
10:37 PM rue_shop1: yea, it reports the position
10:38 PM Tom_L: same damn calipers...
10:38 PM rue_shop1: the new ones dont have them
10:38 PM rue_shop1: all the origional ones had them
10:39 PM rue_shop1: there is an open source thing to hook up to it
10:39 PM Tom_L: nice
10:40 PM Tom_L: what sort of plug?
11:01 PM rue_shop1: I dont know what they used
11:01 PM rue_shop1: I think you have to custom it
11:06 PM Tom_L: do you have the pinout?
11:06 PM Tom_L: + - and 2 signal?
11:29 PM Tom_L: https://www.instructables.com/id/Caliper-Data-Interface/
11:31 PM rue_shop1: it works!
11:31 PM rue_shop1: I have a 2 output floating gate drive supply!
11:31 PM Tom_L: nice
11:31 PM rue_shop1: its all online for the calipers, I'v never bothered saving it
11:32 PM Tom_L: not something i would probably use
11:33 PM rue_shop1: its for a motor driver
11:34 PM Tom_L: i thought you were done with that
11:34 PM rue_shop1: hu? no
11:34 PM rue_shop1: I need to make the motor drivers for the cnc
11:34 PM rue_shop1: I know how I'm going to drive the fets, but need floating supplies
11:34 PM Tom_L: right
11:34 PM rue_shop1: so I needed to make transformers
11:35 PM rue_shop1: and so I decided to redo the coil winder
11:35 PM rue_shop1: this is good, I can drive this direct with a TL494
11:35 PM Tom_L: i should sleep
11:44 PM rue_mohr: at some point
11:45 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1150288.jpg
11:45 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1150289.jpg
11:45 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1150290.jpg
11:45 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1150291.jpg
11:45 PM rue_mohr: it works!
11:45 PM rue_mohr: no shorts, and all the coils are the right way around