#garfield Logs

May 14 2023

06:03 AM rue_mohr: I got the steering working
06:14 AM rue_mohr: yes, its 4am here
06:14 AM rue_mohr: then I made a drive axle
06:29 AM rue_mohr: ready?
06:29 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1280434.jpg
06:29 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1280435.jpg
06:29 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1280436.jpg
06:29 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1280437.jpg
06:29 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1280438.jpg
06:29 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1280439.jpg
06:29 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1280440.jpg
06:29 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1280441.jpg
06:29 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1280442.jpg
06:29 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1280443.jpg
06:29 AM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1280444.jpg
06:30 AM rue_mohr: I made the new large pulley
06:30 AM rue_mohr: rigged up all the steering and realized it was backwards, tore it all apart, made a new pulley system
06:30 AM rue_mohr: then set up some brakes and did some slope tests
06:30 AM rue_mohr: it steers kinda fast
06:31 AM rue_mohr: then I built the drive gang axle
06:31 AM rue_mohr: maybe tommorow I can get some pedal power going
06:31 AM rue_mohr: oh and I changed a flat tire, tried to patch a second one, but it didn't take
06:31 AM rue_mohr: it rolls easy
07:31 AM aandrew: interesting steering assembly
07:31 AM aandrew: rue_mohr> I was surprised the rise time on a PWM step was as bad as it was
07:32 AM aandrew: it can be if the driver is OC or it's a particularly weak bipolar output
07:33 AM aandrew: now you've got me thinking about PWM -> V, if you put a voltage follower opamp before the RC that'd help, but if the input is still stupid slow I wonder if taking advantage of the "edge detector" type of circuitry on some TXS/TXB style voltage translators would help
07:33 AM aandrew: ie when you detect a rising edge your output "snaps" to high output
07:34 AM aandrew: what did the interesting circuit you found do?
11:36 AM rue_mohr: I used a 4069 gate
11:36 AM rue_mohr: I did two inverters
11:36 AM rue_mohr: --|>o---|>o---
11:37 AM rue_mohr: and used the outputs from each inverter to drve it
11:38 AM rue_mohr: https://www.ednasia.com/cancel-pwm-dac-ripple-with-analog-subtraction-revisited/
02:59 PM aandrew: seems like a similar idea; the old inverters work well as analog buffers
03:01 PM aandrew: ahh they're subtracting the ripple there
03:08 PM rue_shop5: yup