I tried various videos and tutorials over the last two weeks to get my RPi3, Chrony and Adafruit GPS talking without success. I came across your video tutorial and written article, and was up and running in a very short time. Thank you so much, both the video and the article have been an invaluable resource. I was about to give up 😊
I accidentally got a module that didn't have PPS broken out to a pin, but it did have an LED. I was able to tack a wire to the LED's resistor and brought that over to the Pi. It's working great, but I know what to watch for if I get another GPS module.
Do you know of a way to actually display the time with high accuracy ? Looking at it through the terminal, the network jitter is not controlled an the frame rate is very low, less than 10Hz. I'm trying to display accurate time to at least millisecond on every frame, so at minimum 60 FPS and hopefully more in the future.
60 FPS is still 1000/60=16.6ms lag. I am not sure of the best way to display super high accuracy time. You'd need at least 1000 FPS to do 1 ms resolution. Why do you need such high accuracy/resolution? The human eye is not capable of detecting much above 100 FPS.
Also read up on JND (just noticeable difference), which is the study of the precision to which humans can detect visual or auditory changes. I believe it is 15-20 milliseconds for visual.
I was trying to use this as a NTP server for my local network, but it seems like it will not work without one external NTP server lookup. My local ISP is having an issue with NTP traffic that they are still looking into. Any thoughts on forcing chrony to use PPS only?
This is not working for me, after installing everything /dev/ttyS0 doesn't seem to exist so nothing works. Any ideas on how to troubleshoot? My GPS "fiX" light is showing that I have a fix so that should be working.I'm on a PI5 if that matters.
Hey Austin, got the stuff in to get PPS set up. Is there any reason for pps_core to not show up when I run `lsmod | grep pps`? I have the first line, as this: ~ $ lsmod | grep pps pps_gpio 16384 0. Any idea what I need to do to fix? FWIW, it doesnt seem to make a difference as I am getting great PPS accuracy. I just wondered if maybe tyhere is something I would need to do to correct that. Looking again after completeing the tutotrial, I see this now: pps_ldisc 16384 2 pps_gpio 16384 2. I dunno.
I don't have an immediate need, but it's nice to see a detailed vid of a real-world project.
I tried various videos and tutorials over the last two weeks to get my RPi3, Chrony and Adafruit GPS talking without success. I came across your video tutorial and written article, and was up and running in a very short time. Thank you so much, both the video and the article have been an invaluable resource. I was about to give up 😊
You are welcome! Glad I could help! Seeing those super small offset values is so satisfying.
Much better than those without the 1PPS synchronization. Well done.
Great video Austin! Thanks!
Thanks Dale! Hope you found it informative/useful!
@@austinsnerdythings2542 yes I use a Raspberry Pi 3 Model B+ For my repeater controller on the my GMRS linked network.
I accidentally got a module that didn't have PPS broken out to a pin, but it did have an LED. I was able to tack a wire to the LED's resistor and brought that over to the Pi. It's working great, but I know what to watch for if I get another GPS module.
Question, sir: what would it look like if you used the WWVB long wave radio broadcast as your time source? Your help would be greatly appreciated.
Do you know of a way to actually display the time with high accuracy ?
Looking at it through the terminal, the network jitter is not controlled an the frame rate is very low, less than 10Hz.
I'm trying to display accurate time to at least millisecond on every frame, so at minimum 60 FPS and hopefully more in the future.
60 FPS is still 1000/60=16.6ms lag. I am not sure of the best way to display super high accuracy time. You'd need at least 1000 FPS to do 1 ms resolution. Why do you need such high accuracy/resolution? The human eye is not capable of detecting much above 100 FPS.
Also read up on JND (just noticeable difference), which is the study of the precision to which humans can detect visual or auditory changes. I believe it is 15-20 milliseconds for visual.
why can't the usb GPS module work for sub nanosecond ?
Dope
I was trying to use this as a NTP server for my local network, but it seems like it will not work without one external NTP server lookup. My local ISP is having an issue with NTP traffic that they are still looking into. Any thoughts on forcing chrony to use PPS only?
I must of had a issue with the chrony.conf file. I reinstalled and configured the pi, everything works great! Thanks! It is a pain to not have NTP!!
Can anybody suggest a method to implement the same on RockPi
This is not working for me, after installing everything /dev/ttyS0 doesn't seem to exist so nothing works. Any ideas on how to troubleshoot? My GPS "fiX" light is showing that I have a fix so that should be working.I'm on a PI5 if that matters.
Hey Austin, got the stuff in to get PPS set up. Is there any reason for pps_core to not show up when I run `lsmod | grep pps`? I have the first line, as this: ~ $ lsmod | grep pps
pps_gpio 16384 0. Any idea what I need to do to fix? FWIW, it doesnt seem to make a difference as I am getting great PPS accuracy. I just wondered if maybe tyhere is something I would need to do to correct that. Looking again after completeing the tutotrial, I see this now: pps_ldisc 16384 2
pps_gpio 16384 2. I dunno.