Archive for November, 2018

What a lemon

Posted in Rant on November 30, 2018 by asteriondaedalus

Samsung J5 Pro.

Had it a couple of months.

Had a thick Gorilla glass added.

Had a thick carbon fibre case.

Dropped a few 10s of centimeters to land flat on screen.  So actually buffeted by both rim of case and protected by G-G.

Even with the reduced jarring the LCD failed.  Phone is kaput.

In fact no visible physical damage externally.  Just a bleeding LCD internally.

I took it back to Optus store, too bad it is “physical” damage.  They recommended going to Samsung store.  I went to Samsung store and the young guy shrugged.  He, the Samsung rep, recommended that he would not recommend the J-series phones to anyone.

The phone cost $300.  I would cost most of that to repair.

It is a $300 dollar disposable phone.

Now there is talk in Australia about the need to bring in Lemon Laws for cars.

Why stop there.  Stop telcos selling lemons as phones. 

As an Engineer I have to say that I was disgusted with how little kinetic energy was required to frag the phone.

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Pegaleg

Posted in ESP8266, MQTT, node-red, OpenSprinklette on November 11, 2018 by asteriondaedalus

So, one file I had fun getting off my laptop was the source for the parser for the google calendar event titles.

The titles, as discussed previously, would be a list of sprinkler group or unit callouts.

I managed to ssh onto the laptop from my desktop to lift anything I wanted before I trashed the laptop with a clean Debian install.

While waiting for the install, I opted to tart up the parser with some sanity.

The problem for the distributed opensprinklette design is that there is no editor per se to police the entries in the google calendar event title. So, if any unwanted text is in the title, the parser running on the node-red server will drop the lot. Harsh I know, but the distributed nature of this entails some trade-offs.

So, I did add some smarts to avoid sending repeated call-outs to a sprinkler. A burst of call-outs will go out once the event title is parsed. The ESP8266 gadgets don’t mind if a single sprinkler is pummelled – it simply results in the time starting from the last received call-out – which won’t be that many milliseconds behind the first.

Still, to opt for a defensive scheme meant testing for a call-out in the return from the scan of the line before adding it to the return. Simples tick!

So, even if the user pummels the title of the event with multiple call-outs to the same sprinkler, the parsed response will only contain a single call-out.

So something like this in the google calendar title:

group1=1;group1=[1];group1=[2,2,2,4,4,4,4,1,1,1,3]

will return the following in the node-red response (prior to fully concatenating into a MQTT topic):
[
"group1/1",
"group1/2",
"group1/4",
"group1/3"
]

Crap!

Posted in Rant, The downside of Opensource on November 11, 2018 by asteriondaedalus

So, found I couldn’t run tensorflow on my laptop as the older i5 I am running is missing an instruction extension to support vectorisations.

I thought then to try to get cuda toolkit up so I could use pyCuda or Cuda accelerated pyTorch.

I got the nvidia driver installed for the GeForce GT 420M my laptop was running. Tricky since I am running Debian 9 Stretch and nvidia is anti-Debian.

Tried unsuccessfully to get pyCuda to talk to cuda toolkit.

There is no official support for the kit on Debian so I had to rely upon vain attempts by others.

I eventually found a good blurb on the problem, but my machine started blurting out app crash reports from the desktop. They kept coming through as often as I closed them. I decided to reboot.

DOH!

Laptop came up without desktop running.

A little poking round and I worked out that sddm was not running and would not run. So, no sddm, no x-windows, no desktop. Kulprit appeared to be the nvidia supplied driver for the 420M.

I tried uninstalling the nvidia driver but the driver uninstall defaults to not recovering your x-windows setup. Unfortunately, I must have twitched on the enter key so nvidia uninstall wiped itself clean, except for the x-windows config.

I poked around and found one config file that needed to have nvidia changed to nouveau BUT there was no information on the extent of mods to files required to manually backout of the nvidia driver callouts in the x-windows.

I was stuck with no desktop.

I also found I was now also sans wifi and likely few other things so I elected to rebuild the laptop (again). That is the standard approach to dealing with linux is it not. If only that was not such a drag.