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1answer
153 views

Cannot ping localhost

While setting up an ntp client/server, I found a weird error where the client cannot check it's own time. I have traced this back to the fact that all of these commands time out: ping localhost ping ...
0
votes
1answer
81 views

Automatically synchronise time with mac on local network without internet access

I want my RPi to have the same time as my mac that I use to command it using SSH. The RPi and mac are connected on a local network without internet access. Currently each time the RPi restarts or ...
1
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2answers
44 views

why two RPis show quite different ntp results?

I have two RPis running on the same network, with the same Internet access. One of them is a B and the other one a B+ model. Both run the same distro with ntp enabled for quite a long time (this is to ...
4
votes
2answers
303 views

How can I get a clock in C accurate enough to control a servo?

I want to write a program that controls a servo motor myself using a pi B+. Controlling the motor involves sending 1.5 millisecond pulses along a GPIO pin every 20 milliseconds. I have tested the ...
0
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2answers
100 views

Installing Tracks 2.2.3 on Raspberry Pi

I want to install Tracks on my Raspberry Pi for task/time management. My Pi is running the latest Raspbian, i.e. I have updated it to the latest package versions. There is a rather cryptic guide on ...
1
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0answers
76 views

ntpq -p reports all available servers have stratum 16

ntpq -p reports all available servers have stratum 16. Therefor the time is cannot be set. However I can ping all the servers. ntpq -p remote refid st t when poll reach delay ...
0
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2answers
61 views

Smallest interval that RPi can record

I was planning to determine light speed by myself(which is 3*10^8 m/s). I have kept 2 sensors, and I need to know the time interval as light strikes the sensors. It lies somewhere about 50nanoseconds. ...
1
vote
0answers
37 views

Reliable timed system with low power consumption over rasbpian [closed]

I'm building a simple irrigation system which uses a Raspberry Pi to open and close a solenoid water valve. In general, the system should open the valve for set intervals of time every so often (E.g. ...
0
votes
1answer
291 views

Chrony 506 Cannot talk to daemon

I'm having trouble configuring chrony to sync the time between my raspberry pi and a desktop computer in an isolated network. My raspberry pi's chrony.config file looks like this: server master ...
5
votes
2answers
206 views

Make RPi keep an semi-accurate time after power loss

I use Motion detection and a webcam as a security camera. It's headless with no internet or keyboard. To turn the camera off while it's not need I just turn the power supply off. Because I shut it ...
4
votes
4answers
4k views

After reboot, my RPi is one hour off — How to adjust for Daylight Savings problems?

The electricity to my apartment went out a few days ago. I use my RPi to record data and store it in a database. I've just learned that the time for all my data has been off by an hour because the ...
7
votes
3answers
2k views

How does Pi keep track of time interval?

As I understand RTC is needed to keep track of time. However, Raspberry Pi does not have that and use NTP servers to synchronize its time. All that is fine, but how does Pi know that one millisecond ...
21
votes
5answers
60k views

Where does the Raspberry Pi get the time from?

I don't have to set the clock (besides the timezone) on the Raspberry Pi. Where is it getting the time from? About how accurate is it?
10
votes
4answers
5k views

How is time kept on the Raspberry Pi?

How is time kept on a Raspberry Pi with the latest Raspbian release? What sets the internal clock from an NTP server? What happens when no NTP server is available? From my program I am trying to ...
11
votes
2answers
2k views

How accurate is Raspberry Pi's timekeeping?

I realize that since Raspberry Pi doesn't have a real-time clock built in, some issues with accurate timekeeping may present themselves, even when persistence across reboots is not a requirement. This ...