Backup battery for clock?

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Mimamau
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Backup battery for clock?

Post by Mimamau » Tue Mar 24, 2015 3:45 am

Is it possible to add a backup battery for the hardware clock?

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pete
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Re: Backup battery for clock?

Post by pete » Tue Mar 24, 2015 5:27 pm

Personally I think you can.

Historically here went sleuthing around the Openpeak II motherboard as it does have a battery backed up clock.

The design of the O2 Joggler motherboard comes from the Openpeak 1 device; just minus a few pieces of hardware as similiarly the Openpeak 2 device has the most bells and whistles.

All that needs to be done (personal guesstimate) is finding out what it is that is connected to the clock on the Openpeak II device and replicate to the O2 Joggler / Openpeak 1.

You can purchase an RTC battery clock for cheap these days and they are small enough to fit inside of the O2 joggler.

The battery in the picture only has two leads like any other type of DC CMOS battery.

Here is a picture of the battery stuff on the Openpeak 2.
OpenFrame2Battery.jpg
One (well many of the widgets on my home network) have no clocks. I did purchase an RTC clock for one RPi and it works well especially when utilized for automation stuff.

Today my Firewall (PFSense) is using a GPS/PPS for its time (now too its an NTP server) and I proactively block internet NTP on the edge such that all of the widgets get their time from the firewall. Same goes for DNS being blocked today.
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Juggler
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Re: Backup battery for clock?

Post by Juggler » Fri Jun 12, 2015 12:44 pm

You can get little RTC boards with battery and an I2C interface for around a dollar. The joggler has an I2C interface internally. A different website details a project to use the I2C interface. It would then just be a matter of hooking up the RTC board to the right place on the Joggler, and then using some software (I think there is some good I2C hacking software for Linux), so that the time from the RTC can be read on boot and update the system time. Also to keep your RTC correct you would need to write a script or something that would take data from and NTP query and set the RTC from that. I think you would be covered then. Using the Joggler's I2C interface may not be straightforward.

Other solutions, may be to use a USB GPS and set the system time from that. No need for a network connection then.

I use a package called fake-hwclock, which remembers the time at last power down and then sets the system time to that. Maybe this would be helpful, so you don't have a time back in the ?70's?.

http://manpages.ubuntu.com/manpages/tru ... ock.8.html

HTH

Juggler
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Re: Backup battery for clock?

Post by Juggler » Sat Jun 13, 2015 1:25 pm

These are the best links I can find for I2C on the joggler :

http://www.jogglerwiki.com/wiki/Connect ... he_i2c_bus

http://www.sunspot.co.uk/Projects/Joggler/i2c.html

https://github.com/buserror/minifs/blob ... 2-v1.patch

Sadly, this appears to be the main work, and, AFAIAA, that is about it. But if anyone knows other wise, please let us know. The joggler would be a great device for monitoring / controlling I2C device networks.

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pete
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Re: Backup battery for clock?

Post by pete » Sat Jun 13, 2015 8:48 pm

Thank you HTH!

Yup here went to a hodgepodge of use of the Joggler tablets. They are all over the house. I have moved the Wintel tiny build XP tablets to XP Embedded and they work well this way. One of the issues with Wintel / battery / RTC / Realtek NIC was that it didn't work in Wintel. There is a little trickery to get it to work but I do have them now connected via Gb and they work fine. That said if the power is pulled then issues.

Here too I am not internet dependant on my time; rather its a GPS / PPS serial connection to my PFSense firewall and I block NTP in/out of the firewall . Been using an NTP server here now for more than 10 years now. Same with DNS as no device gets its DNS from the internet; rather it just uses the PFSense firewall for DNS.

Unrelated to the Jogglers here been playing with the RPi2's and default build now is with the PiFace RTC Shim which works well. I have one RPi2 configured with a GPIO Z-Wave Plus card in addition to the PiFace clock and it works well.

I use a package called fake-hwclock, which remembers the time at last power down and then sets the system time to that. Maybe this would be helpful, so you don't have a time back in the ?70's?.

Thank you HTH. I installed this on my Linux based Jogglers over the last few days.

This is the top pieces of the way I have my Jogglers organized. I use the names and MAC addresses to remember which Joggler is where here in the home. There is a tiny client connection which manages the hardware remotely from the mothership and is predefined per Joggler.
automationJogglers.jpg
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pete
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Re: Backup battery for clock?

Post by pete » Sun Jun 14, 2015 5:03 pm

This morning googling a bit found a USB based RTC clock.
RTC-USB-1.jpg
RTC-USB-2.jpg
Most if not all of my Jogglers has an extra USB port set up in them via a bit of thin wiring.

Installing a USB based RTC clock would be easier to configure both software and hardware wise. Well and you can hide it inside easy enough.

Going to give this a try as it is inexpensive and I can test very easy.

You still use the I2C interface for the RTC.
RTC-USB-3.jpg
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