(Reprise) Adding a Real Time clock to DexterO/S


Please see the original article discussing this topic located at:
Adding a Real Time Clock to the GoPiGo

Though this may seem like re-posting the same question to a different thread, (obviously bad), I am creating a new thread because:

  1. The original thread is somewhat old and most fora tend to get annoying when you resurrect old threads.
  2. This question is sufficiently different, that I believe an entirely separate question is in order.

If I have inadvertently offended, please accept my apologies.

Dexter OS does not have any semblance to a reasonable clock, (at least as of version 2.2.2, I have not yet powered up Charlie with 2.4.4.) The result of this is that both file time-stamps and (more importantly) log file entries make no sense due to the time being off by insane amounts.

Proposed solution:
I have purchased (several) hardware Real Time Clock modules from Adafruit, and they have a nice tutorial on how to add true hardware RTC support to the Raspberry Pi.
Viz.: Adding a Real Time Clock to the Raspberry Pi

The article is several pages long, but at the end of it all you have a version of Raspbian that has true hardware RTC support.

Even within a classroom environment (<<== Hey Bosses!! Hint! Hint!), the ability to troubleshoot using log files is essential - maybe not for the students, (at least not at the beginning), but it can be essential for an instructor trying to make sense out of a classroom full of non-functional GoPiGo robots.

This issues is compounded by the fact that due to any kind of RTC support and/or internet connectivity, time stamps can be difficult to use.

Dexter OS does not support any kind of “root” access, at least without a lot of painful hacks that might cause more trouble than they are worth. So, the normal “sudo-this-and-that” approach is unavailable.


  1. Is it possible (in the current 2.4.4 version of Dexter OS), to run commands as root via sudo?
  2. Absent that, is it possible to gain access to the content of the O/S on an external Linux system and edit certain files to:
    a. Disable the “fake-hwclock” feature
    b. Enable the real hardware RTC using equivalent techniques as noted in Adafruit’s article?

I strongly suspect that adding RTC support in Raspbian for Robots is essentially the same as any other version of Raspbian. However, I would like to know - both for myself and for others - how to enable this in Dexter OS and/or Cinch. Preferably both.


Jim “J.R.”

This is confusing to me - Why are you using DexterOS?

With Raspbian4Robots, Carl gets time from the Internet (shortly after boot), so all files created or modified, and user logs (using Python logging) have the correct time. (I purposely wait 1 min after boot before starting my life.log program. )

System maintained logs do not get a real time, but I have not needed any of them, ever.

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Why did Hillary climb Mt. Everest?
Why did the Wright Brothers try to build an airplane?
Why did the U.S. send a man to the Moon?

Why? 'cause we’re all bloody masochists! :wink: (and doing things the easy way is no fun at all.) In all seriousness, the best way to get me to latch onto a project like a bulldog is to tell me “it can’t be done”.

Dexter OS can’t connect to the Internet so it cannot get a time sync. So. . . . I wanted it to be able to maintain it’s own sense of time. Of course, I’ve got plans for Raspbian for Robots too. . . .

As I figure it, there are three possible outcomes:

  1. The people here at Dexter Industries tell me what I need to know, and I get it working.
  2. Absent that, the people at Adafruit will tell me what I need to know, and I get it working.
  3. And if THAT doesn’t work, I’ll have to figure it out by myself, and get it working.

However, I like to try the easy ways first. Re-inventing the wheel is usually saved as a last resort if at all possible.

I too get easily distracted.

Concerning 1) - Dexter, now part of Modular Robotics is giving away their software for free, so I rather doubt their interest in improving Dexter OS for a special case - most teachers rewrite the SD card between uses these days to keep things exactly the same.

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True, oh wise one! Though in this case I’m not necessarily asking for a re-spin, just a few hints on what to do. Maybe there are teachers who are interested in this kind of stuff, maybe not. All I can do is ask.

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Hi Jim
DexterOS is a closed box, so you are not meant to access the OS and run anything with sudo.

Raspbian for Robots will have no problems supporting the RTC.

As an aside, this exact situation was discussed internally when we designed the GoPiGo3. I lost.