Saturday, 22 November 2014

No News Is Good News

Not much happening on the blog at the moment, mainly because there's nothing to report.  The system continues to run reliably, and the uptime is currently showing 377 days.

I permitted myself a small pat on the back as the uptime passed one year, but the record remains 550 days, and I don't think we're going to break that on this run because I have a couple of software improvements in mind which will require a restart to implement.

Still, this certainly shows that the Raspberry Pi is much more than just the cheap educational toy that some people have characterised it as, and is well capable of "professional" performance.  I like to think it also says something about the quality of my software.

Wednesday, 28 May 2014

"Hardware" Failure

The Polly system needs to know whether it's dark or light, of course, and this is achieved by a little circuit with an ORP12 light dependent resistor measuring the light level.  This is mounted in a plastic box with a translucent lid, fixed to the inside of a window.

This week the plastic succumbed to the effects of 21 years of sunlight and burst into a shower of dust.  A true hardware failure!

With the aid of a hot glue gun I've installed the board in a new box and remounted it on the window.  I suppose I ought to make a note in my diary to replace it again in the 2030s.

The electronic and software parts of the system continue to perform well, and as I type the uptime is 199 days, and counting.

P.S. You might think that when I wrote "a little circuit" above, that seems a bit vague.  Well, to be honest I've no idea what's in there, and there are no surviving notes from 1993.  Probably a 741 op-amp as a voltage comparator, I guess.

Tuesday, 7 January 2014


I haven't posted anything here for some time, so I think an update is in order:

I had some problems back in October which turned out to be due to the cheapo SD card I was using:  On a couple of occasions I found the system working but reporting errors when it tried to write a file.  I ssh'd in to find the entire file system was read-only - presumably as a result of some sort of error, but I couldn't find out what the error was because, of course, it couldn't write to syslog.  A reboot restored normal service but a few days later the problem occurred again.  The third time the system refused to reboot.  I put the SD card into my main PC and it wasn't detected.  So, having already bought a new card after the first failure, I quickly installed the latest raspbian build on it, installed polly, copied all the config files from the most recent backup (Fortunately I've got daily backups running.) and normal service was resumed.

Since then the system has been much more reliable, and it's currently showing 58 days of uptime.  (The all-time record uptime was 550 days, ending in December 2001 when I accidentally unplugged the server!  This was the DOS-based version.)