Jeeze this would look strange from a distance. It's a dark damp
night with no moon in the sky, the only sound is distant frogs
chirping from every angle, and here at the side of an empty paddock
there's a square block of light from a twenty year old Thinkpad
illuminating a figure of a man sitting on a surprisingly not wet
rock. The local kangaroos do regularly come into this paddock in the
evenings so I may be ROOPHLOCHing with the roos, but then again I
could be ROOPHLOCHing with a elephant for all I'd know in this dark.
In fact the deep thuds of a roo bounding about probably wouldn't be
that welcome when I can't see what it's coming from.
Anyway this is a bit of a last minute entry because I wanted to test
out [first mozzie] an optical communications system. Long story
short, I didn't manage to get it together in time. I did buy a
photodiode ages ago, and a few days ago I finally got around to
building an amplifier and comparator circuit for it, which could
then be interfaced to a PC serial port. The amp circuit is a pretty
simple current to voltage converter application, but conventionally
it requires a split supply. However I found an example circuit from
TI for a single-supply design, and although I didn't have the op-amp
specified it seemed pretty clear than any FET-input op-amp should
do. Three hours, and two models of substitute FET-input op-amps,
later I finally concluded that there was more to the circuit than it
seemed. I still don't know why it didn't work to be honest, but
[first moth to the screen] actually two battery packs for a
split-supply circuit isn't that hard to accomodate and with that
everything started working as expected.
But I was only getting about 1m range testing with the spare panel
of 26 red LEDs that I had handy, so I then went hunting through all
the spare lenses from old projectors and camera junk, and eventually
found a combination of what I think is a 8mm movie camera telephoto
lens and a projector lens which seems to get me at least three
meters (and as far as I can get away from my workbench).
Trouble is, at that point I didn't feel like doing an all-nighter to
try and rig up the serial interfaces (also for the LED transmitter),
and fix the lenses in some positionable way. The days since have
been pretty busy, so it wasn't worth it for the sake of a
self-imposed restriction on a fairly irrelevent challenge.
Anyway, optical communications aside, it's been a crazy time in Aus
lately, and particularly last week. The lockdowns in Melbourne
spread to my area (actually I was on the border, at the wrong side
of the road), though thankfully ended last week. In Melbourne there
were angry mobs confronting police, and it's interesting to compare
media coverage of that with eg. the protests in Hong Kong, or even
the US. Here lots of shots of mobs waving banners, but not much of
the riot squad swarming them and shooting things as was on
apparantly shown on social media. I think the protests were stupid,
but like with the media's coverage of Trump evident bias actually
makes me feel more defenceive of them.
[shutdown, batter swap, restart]
OK I'm now on my second battery (I got two about seven years ago and
by now they both only last about an hour), at least that got rid of
the moth. Hey, an hour, and I started this after 11:00PM... Bugger!
12:00AM exactly, I missed the deadline. Oh well, it's probably still
yesterday whereever it is in Europe that SolderPunk lives, us
Aussies have the luxury of coming to you from the future.
I'll skip commentary on the nuclear sub deal, and as a nuke nut
that's not easy, and go onto [now that's a weird looking bug...] my
first earthquake experience before I leave you. The state of
Victoria has it's strongest recorded earthquake, around magnitude
six which is apparantly the same as the Christchurch earthquake in
NZ, but this one was out in the mountains about 100Km from Melbourne
and a few more 100Km from me. Still, I was busy trying to solder
together circuit boards and actually I thought I'd was going giddy
on the solder fumes or something except the curtains seemed to be
moving as well. I never realised the it's almost as hard to tell
what's going on in an earthquake in real life as it looks in on TV -
the only cues are equally explainable as draughts in my house,
except that there didn't seem to be much wind (the childhood
education that we don't get earthquakes in Austrlia doesn't help
either of course - is anything they taught me at school genuinely
true?). In fact in the strong winds I get out here I would have
easily believed it was the house rocking against the force of a gust
on a blowy day. Anyway I got up and went outside, partly to see
whether I could walk or was about to pass out on the floor, and
partly to see whether the apocalypse was neigh. By the time I got
out it was all over and, after checking that the house wasn't
collapsing and there weren't any mushroom clouds on the horizon
(nuke nut, like I said) I went back in and called my father. He'd
been outside and assured me he hadn't felt a thing, so after that I
was sure I was going crazy. But he did call back after other people
had apprantly asked him whether he'd felt the quake, and there was
plenty on the news that night.
Well it turns out the open surrounds make me open up, even if I
can't see them, and I've babbled on plenty. I'll try to upload this
now over boring old mobile broadband, not that it's always a sure
thing either. Then I'll try to make my way back to the house without
getting tagled up in old fencing wire again. It didn't start raining
at least, so that's nice. In fact the nights have been so cold for
most of this month that I wouldn't have had much opportunity to do
my optical comms experiment anyway (assuming it doesn't work very
well in daylight).
Goodbye from me and the roos (maybe).
- The Free Thinker.
Oh, the LED on this mobile broadband modem is REALLY BRIGHT!
Rats, the rules say by midnight local time, oh well. Thursday
is the only day of the week when there's actually some decent
stuff on TV so what hope did I have? :)
