In the event of a power outage, an analogue power socket timer switch will simply turn off. When then power returns, the unit is not aware of how long the power has been out for and the timer will continue from when the power cut.
If a digital timer is used, on power being restored, the time should be correct with your on/off schedule preserved.
When using a Linux system (Raspberry Pi) and Cron to set a scheduled task, if a power cut occurred within the time an action was supposed to initiate, this window will be missed as when the system power is restored the action event would have passed and won’t be initiated until the next scheduled time.
For the ARPIC or Linux system to act like a 7 day digital timer a script is used on start up to check the time.
Continue reading ARPIC – Time Check Boot Script
Whilst setting up a new APRIC I noticed that the time was not updating as expected, no update on boot.
I have not setup an RTC on this unit yet, but NTPD would need to be installed anyway to updated the RTC later.
It appears in the Jan 2018 release of Rasbian Lite Stretch does not have NTPD installed as default.
A quick way to check the time and date configuration is to use timedatect1
Continue reading ARPIC – Raspbian Light Stretch NTP
ARPIC – Another Raspberry Pi Controller
4GB or larger Micro SD card
Network connection – cable or WiFi
PC with an SD card reader (Windows OS in this example)
For help getting Raspbian onto your SD card, take a look at these pages;
Lets get started!
Continue reading ARPIC, Install Raspbian Lite onto a Raspberry Pi
How to read a temperature probe, save the value to a MySQL database and then show the value on a webpage or just show the value with no database.
See this link for how to setup a DS18B20+ thermal probe with a Raspberry Pi, these instructions are the best that i have come across for this and will cover the bullet points below :
- Enabling the 1 wire features in the Raspbian OS
- Physically connecting the probe via a resistor to the RPi
- Instructions on how to read the probe and a script example
Once you have followed the above steps you should have a working temperature probe, that’s great.. but what can you do with it now!?
Continue reading Raspberry Pi Thermal Probe
Information directly copied from : https://www.cs.cmu.edu/~help/networking/ntp.html –
for quic ref…
Windows 7 systems benefit from using the full set of NTP servers, but cannot be configured to obtain NTP server information from DHCP. Because the control panel does not allow setting multiple servers, settings on these systems must be verified and changed from a command prompt. Systems which are members of the SCS domain will receive NTP configuration via domain group policy and should not be reconfigured.
Continue reading Configure Client Network Time (NTP)