#garfield Logs
May 15 2020
#garfield Calendar
12:31 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1160110.jpg
12:37 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1160112.jpg
12:37 AM rue_mohr: ma found an old table from a store clearing out
12:37 AM rue_mohr: it was a perfect fit for the cart
12:37 AM rue_mohr: so today I put that on
12:37 AM rue_mohr: mounted the charger, but its got a 'charger plugged in, not allowed to drive away' detector I need to defeat
12:37 AM rue_mohr: was playing with a VFD screen too
12:37 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1160127.jpg
01:01 AM aandrew: wow
01:03 AM aandrew: rue_mohr: that is really fucking cool
01:05 AM rue_mohr: aandrew, that sounds like pain
01:06 AM rue_mohr: thats to use extenal memory?
01:06 AM rue_mohr: which is cool? :)
01:07 AM aandrew: no
01:07 AM aandrew: MPU is memory protection unit
01:07 AM aandrew: think primitive MMU
01:09 AM rue_mohr: oooh, cmon now, its an mcu, dont be trying to do operating system things!
01:10 AM aandrew: heh
01:10 AM aandrew: well the MPU here is being used for CE compliance (safety software)
01:11 AM aandrew: so I defined a 1k region at 0x0 to crash if you try to dereference a null pointer
01:11 AM aandrew: and I have another region defined Read-Only for some critical structures
01:15 AM aandrew: eventually I'll use the MPU to protect SYSTICk and a couple other timers which control the encoders
01:47 AM rue_bed: oo ok!
01:48 AM rue_bed: safety software, does it all get cross checked?
01:59 AM rue_bed: I need to make up a screen and an encoder-knob interface
02:00 AM rue_bed: then I have all the components for the software
02:00 AM rue_bed: still need to make the other resistor modules too
02:00 AM rue_bed: then a power supply
05:14 AM polprog: rue_bed: nice VFD
05:14 AM polprog: how do you power the filaments? whats the anode voltage
06:51 AM Tom_L: hello
06:51 AM polprog: hi
06:58 AM polprog: https://www.ralphs-pugh.com/engineering_data/chemical_resistance_chart.html
06:58 AM polprog: useful link ^
06:58 AM Tom_L: i used to have one for paint
06:58 AM polprog: i could use one for paint
06:58 AM Tom_L: it's long gone :(
06:58 AM polprog: i was wondering how to clean paint off spray can caps
06:58 AM Tom_L: should just peel off
06:58 AM Tom_L: it's plastic
06:58 AM Tom_L: even that krylon for plastic doesn't stick like i'd expect
08:52 AM rue_mohr: polprog, I'm using the doubling effect of the pushpull for high voltage, so its 24V
08:53 AM rue_mohr: the filament is +-4V
08:53 AM polprog: hmm
08:53 AM rue_mohr: from the same transformer as the HV
08:53 AM polprog: doubling effect? never heard
08:53 AM polprog: or i dont know what you mean
08:53 AM rue_mohr: pushpull transformer
08:53 AM rue_mohr: when you ground one side of the winding, the toher side goes up to twice the supply voltage
08:54 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1160130.jpg
08:55 AM rue_mohr: the core runs warm, I thought it would work better with a core that had a sharper saturation, but I think it needs to be softer
08:55 AM polprog: hmm, neat
08:55 AM polprog: whats the core?
08:56 AM rue_mohr: its half that EMI bead I cut in half
08:56 AM polprog: oh, interesting
08:56 AM rue_mohr: high u
09:04 AM rue_mohr: I think having one pullup resistor on the base drive like that throws off the duty
09:06 AM rue_mohr: its a royer oscillator, I need to learn more about optimal design for them
09:10 AM rue_mohr: but it needs to be unblaanced to start nicely
09:16 AM polprog: interesting
09:37 AM polprog: https://i1.jbzd.com.pl/contents/2020/05/qtI2YOpjdXv43PMVzmJEDYL8goPuYE6L.mp4
10:35 AM Tom_L: how to list devices in linux?
10:52 AM polprog: which devices/
10:52 AM polprog: PCI?
10:54 AM Tom_L: nm i figured it out
12:52 PM aandrew: dmidecode?
04:44 PM rue_shop1: lspci
04:47 PM Tom_L: don't work
04:51 PM polprog: http://w3.uwyo.edu/~jimkirk/guidance.wav
04:52 PM rue_mohr: lspci doesn't work?
04:53 PM rue_mohr: polprog, is that just an antistatic bag?
04:53 PM polprog: i think so
04:54 PM polprog: must be a thin one
04:54 PM rue_mohr: yes
04:54 PM rue_mohr: hmmm
04:54 PM Tom_L: spi
04:55 PM rue_mohr: you want to list spi deviceS?
04:55 PM Tom_L: not anymore
04:55 PM Tom_L: but i did
04:55 PM rue_mohr: well you cant
04:55 PM rue_mohr: there is no registration process
04:56 PM Tom_L: what's file compare in linux speak?
04:56 PM rue_mohr: diff
04:57 PM polprog: some SPI devices could show in the kernel message buffer.. if their drivers are initialized
04:57 PM polprog: but i doubt it
04:57 PM Tom_L: what's the /dev/ for a thumbdrive?
04:57 PM polprog: problably /dev/sdX, where X is a letter
04:58 PM Tom_L: how do i list those?
04:58 PM polprog: that should show in dmesg as well when you plug it in
04:58 PM polprog: easiest would be
04:58 PM rue_mohr: they round up everything to look like a scsi disk
04:58 PM polprog: fdisk -l
04:58 PM rue_mohr: ls /dev/sd*
04:58 PM rue_mohr: fdisk is better
04:58 PM polprog: fdisk will show you the size and model as well
05:33 PM rue_mohr: hmm
05:34 PM rue_mohr: I dont think I can beat a tl494 in size and parts count for an RC oscillator and a /2 FF
05:34 PM polprog: FF?
05:34 PM rue_mohr: its drivers suck, but whatever
05:59 PM polprog: i wanna cram an FT232 into a serial modem.. and add a USB-C connector to it
10:19 PM rue_mohr: I want a TL494 with 500mA FET outputs
10:37 PM Tom_L: what's up?
10:50 PM rue_shop1: working on my resistor substitution box
10:51 PM rue_shop1: gonna rewind another transformer
10:51 PM rue_shop1: fixed a crane today, thats a new one
11:54 PM rue_mohr: hmm, nope, need to try something else...
11:55 PM rue_mohr: getting tired of winding toroids...
11:57 PM rue_mohr: I think I need to be under 0.5V/turn
11:57 PM rue_mohr: but I'm gonna hit the amp-turns at some point
11:58 PM rue_mohr: fight between volt*seconds and amp*turns