#garfield Logs

Jun 11 2021

12:34 AM rue_mohr: always@(posedge iCLK)
12:41 AM rue_mohr: if(sr_counter >= 25'd25000000)
12:41 AM rue_mohr: sr_led <= {sr_led[2:0],sr_led[3]};
12:41 AM rue_mohr: else
12:41 AM rue_mohr: sr_led <= sr_led;
12:41 AM rue_mohr: ooh, they... trickey
12:41 AM rue_mohr: trying to work out how that created the chaser effect
12:41 AM rue_mohr: I get it
04:05 AM Tom_L: morning
04:09 AM darkrose: greetings from the evening
08:41 AM rue_mohr: hi
09:59 AM darkrose: rue_mohr: speaking of bigger workshops, I've got my eye on a house
12:17 PM polprog: last ee labs over
12:17 PM polprog: im essentially a free man now
12:18 PM polprog: no exams to do, no nothing
12:18 PM polprog: time to clean the bench and fix up the 100MHz oscillator, make it oscillate at 100MHz
12:38 PM polprog: hmm, so i have an inductor that says 220K on it
12:38 PM polprog: 220uH?
12:39 PM polprog: 22uH
12:40 PM polprog: got a 5.6mH hmm
01:00 PM Tom_L: would a voltage divider work the same for a positive voltage as opposed to a negative voltage on the same pin?
01:02 PM Tom_L: positive feedback turns a motor one way where negative feedback turns it the other however the new part puts out 9v where the old part puts out 8.5v and that makes a big difference
01:03 PM Tom_L: but going the opposite direction those would be negative
01:04 PM polprog: i think so
01:05 PM Tom_L: it's driving some analog feedback to a servo amp
01:05 PM Tom_L: so it needs to be .5v less but linear
01:06 PM Tom_L: i thought about a diode drop but that wouldn't work in the opposite direction
01:15 PM Tom_L: would 2 diodes work?
01:16 PM Tom_L: wired reverse of each other... one for positive the other when it goes negative?
01:16 PM Tom_L: and the opposite would block
02:33 PM polprog: so i added a supposedly matching transformer to my generator
02:33 PM polprog: because i initially measured the output impedance of it to be about 480 ohm
02:33 PM polprog: now its 410
02:33 PM polprog: it was supposed to be 50
02:34 PM polprog: but now it makes 13 MHz with a 40MHz xtal, and doesnt work with the 12MHz xtal
02:36 PM polprog: maybe the core inductance is too low and it looks like a short to the output
02:53 PM polprog: i need some rf chokes
06:32 PM Tom_L: https://media.discordapp.net/attachments/749283134893457459/853040647505444904/E3npZsTWEAEy-57.png?width=512&height=664
06:52 PM rue_mohr: have to reset my brain something of a tressfull day at work
06:54 PM Tom_L: gonna desolder some kbd switches and clean them
06:55 PM Tom_L: unless something better comes along before i get the back off
07:05 PM rue_mohr: heh
07:06 PM rue_mohr: at some point I'm going to break downa nd make a keyboard from scratch
07:07 PM Tom_L: not me. but i do like these
07:21 PM Tom_L: ok so what do you think? disassemble and ultrasonic cleaner?
07:39 PM Tom_L: 8 desoldered so far
07:39 PM Tom_L: they come apart pretty easy
11:06 PM Tom_itx: desoldered several switches and took them apart, cleaned in the ultrasonic cleaner and put back. had a couple with weak springs so i took them back off and tweaked the spring slightly
11:06 PM Tom_itx: http://tom-itx.no-ip.biz:81/~webpage/rue/Omnikey_key/alps3.jpg
11:06 PM Tom_itx: the little 2 prong on the upper left
11:14 PM Tom_itx is now known as Tom_L
11:14 PM Tom_L: the switch is actually just that wafer and the dimple in the spring pushes it together
11:14 PM Tom_L: the other spring is just to counterbalance the blue plunger so it stays centered
11:14 PM rue_mohr: hi
11:51 PM rue_shop5: ok let me catch up
11:52 PM rue_shop5: polprog, what?
11:52 PM rue_shop5: 220 should be 22uH I'm sure
11:53 PM rue_shop5: Tom_L, hu?
11:53 PM rue_shop5: on the 9V/8.5V thing
11:54 PM rue_shop5: Tom_L, hmm what input vs output range do you need then?
11:54 PM rue_shop5: Tom_L, discord?
11:54 PM rue_shop5: Tom_L, hows the keyboard doin?
11:57 PM rue_shop5: Tom_L, yea, I cleaned up a few of those on that keyboard I did
11:57 PM rue_shop5: but after taking on apart, I just gave the rest a small capacitor discharge
11:57 PM rue_shop5: it worked
11:57 PM rue_shop5: I think I gave them something like 6V on a 10uF capacitor
11:57 PM rue_shop5: re-arrange the metal a bit