Precision Timekeeping Fuckery

How it works

Services

• gpsd
• chrony
• telegraf
• influxdb
• grafana-server
• syslog-ng

Testing

Status (Everything)

• bash ~/Precision-Timekeeping-Fuckery/full_status.sh

Status (Services)

• bash ~/Precision-Timekeeping-Fuckery/status_services.sh

Test PPS

• sudo ppstest /dev/pps0

Logs Stuff

Chrony Logs

• sudo tail -f /var/log/chrony/tracking.log
• sudo tail -f /var/log/chrony/statistics.log
• sudo tail -f /var/log/chrony/measurements.log

Telegraf Logs

• sudo tail -f /var/log/telegraf/telegraf.log

Grafana Logs

• sudo tail -f /var/log/grafana/grafana.log

Influxdb Logs

• sudo tail -f /var/log/syslog

Root Crontab Logs

• sudo tail -f /var/log/root-crontab.log

Setup

Requirements

1. Raspberry Pi with
   1. Raspberry Pi OS Light Version Installed
   2. SSH Access
   3. sudo permissions
2. A timing specific GPS module, wired to the Raspberry Pi GPIOs:
   1. GPS GND to RPi Physical Pin 6 (GND)
   2. GPS RX to RPi Physical Pin 8 (GPIO 14 / TX (UART))
   3. GPS TX to RPi Physical Pin 10 (GPIO 15 / RX (UART))
   4. GPS PPS to RPi Physical Pin 12 (GPIO 18)
   5. GPS VIN to RPi Physical Pin 27 (3.3 volts)
3. I2C RTC Module
   1. RTC GND to Rpi Physical Pin 9 (GND)
   2. RTC SDA to RPi Physical Pin 3 (GPIO 2 / SDA1 (I2C))
   3. RTC RCL to RPi Physical Pin 5 (GPIO 4 / SCL1 (I2C))
   4. RTC VCC to RPi Physical Pin 1 (3.3 volts)

Install

Hardware

1. pi4/5 and stuff for it
2. gps timing module
3. rtc
4. battery for rtc
5. wires

Wiring

Pins and Wiring Guide

OS

1. Raspberry Pi OS 64 bit lite
   1. Raspberry Pi imager
   2. Configure in imager
      1. hostname: grandmasterclock
      2. enable ssh
      3. ssh key
      4. username
      5. password
      6. locale
      7. keyboard

Software (Auto)

WILL REBOOT IN BETWEEN EACH COMMAND

1. curl -s https://raw.githubusercontent.com/PrincessPi3/Precision-Timekeeping-Fuckery/refs/heads/main/time_fuckery.sh?nocache=$RANDOM | $SHELL
2. git -C ~/Precision-Timekeeping-Fuckery pull && bash ~/Precision-Timekeeping-Fuckery/time_fuckery.sh
   1. each reboot run the above command a total of four (4) times
3. https://grandfatherclock:3000
   1. default login: admin and admin
      1. set new password
   2. data sources->add new->influx db
      1. name "influxdb1"
      2. query languagew: influxql
      3. http
         1. url: http://127.0.0.1:8086
         2. timeout seconds: 3
      4. database: Chrony_Stats
      5. user, pass: blank
      6. save and test
   3. Dashboards->New-Import
      1. Upload Garfana-Visualization.json

Software (Manual)

Clone the repo
git clone https://github.com/PrincessPi3/Precision-Timekeeping-Fuckery.git ~/Precision-Timekeping-Fuckery

Run raspi-config

1. Interface Options->Serial Port
   1. Would you like a login shell to be accessible over serial?
   2. Would you like the serial port hardware to be enabled?
2. Interface Options-I2C
   1. Enable Yes
3. Advanced Options 1. A1 Expand Filesystem

Clients

Windows

1. Open the Control Panel and navigate to the Date and Time settings.
2. Click on "Internet Time" and then "Change settings".
3. Enable the option to "Synchronize with an Internet time server".
4. Choose a time server from the available list or enter a custom one.
5. Click "OK" to save the changes.

Links

Helpful Guide https://austinsnerdythings.com/2025/02/14/revisiting-microsecond-accurate-ntp-for-raspberry-pi-with-gps-pps-in-2025/

Old Module

• Chipset https://www.u-blox.com/en/product/neo-f10n-module
• Breakout https://docs.sparkfun.com/SparkFun_u-blox_NEO-F10N/single_page/

Current Module

• Chipset https://www.u-blox.com/en/product/neolea-m8t-series
• Breakout https://www.ebay.com/itm/134243322249

U-Blox Software (U-Center) https://www.u-blox.com/en/product/u-center

notes: gps cable delay : RG-85 : 0.051 ns/cm 10ft in cm: 304.8 gps cable delay: 304.8*0.051 = 15.5448ns, round up to 16ns

known bugs