following up on an earlier post,
here are a few more reasons why 3d printers are both cool toys and
i live in a pretty humid climate, and using vacuum storage bags (for
things like spare blankets and pillows) is quite important; but the
dyson vacuum that i inherited from my daughter has this
nice-but-unhelpful clicky connector that sucks because it doesn't
suck -- there's no flat interface that you can press against the bag valve.
so i spent a little time on designing and printing a sucker adapter
(in PETG because i wanted to do more testing with the material).
or this one, from earlier this week: the built-in cupboard in my
hallway has a broken door catch (cylindrical post in the frame,
claspy catch on the door) and i couldn't find any even remotely
similar replacement at the (sole remaining
:-( ) hardware chain.
however, calipers and persistence and one failed test-print later i've
now got a parametric model and an actual replacement part that works.
on the last photo you can see my newest mod to my printer, a mk52 (clone)
magnetic heatbed. the print surface is PEI on a removable sheet of spring steel,
which is held to the actual bed and heater by many strong magnets. when your
print is done you take off the steel sheet and flex that, rather than prodding
and prying with spatula/chisel/knife.
so far it works pretty well, but the bed is made from PCB/fibreglass and
prone to warping. i haven't fully bolted the bed down (like official prusa
does it) because i like the ability to level things manually, but i
may want to change that later; for now i've setup 7x7 grid level compensation
with my smoothieboard clone and that takes care of the imperfect flatness.
[ published on Fri 09.11.2018 17:18
| filed in interests/tinkering
| tagged 3dprinter, openscad, tinkering, smoothieboard
i'm now driving what might conceivably be called a chick magnet car
-- with the understanding that the magnetic attraction is confined to within
the cabin, and the repelling forces work all over the outside. net
result: it'll take a woman of superhuman persistence to actually come close...
click here for the rest of the story...
[ published on Fri 09.11.2018 16:43
| filed in interests/au
| tagged chick_magnet, toy_car, 4wd
(beagle as in 'beaglebone black', which is
not a dog by any means)
almost exactly three years ago i built a minimal-budget
online weatherstation for
fido, john sinclair's fraser island defenders
org. that station was installed at
happy valley and it's been
working pretty well ever since - well enough that we followed it up a
few months later with another station which ended up at
both of these were build on a shoestring budget, and for the second i used
the same fairly yucky 'authentication' chip setup on perfboard and
hacksawed 2mm 2x10 pin connector, and everything was housed in a really ugly
fashion inside a weatherproof box.
recently fido got a budget together for four more
stations. about two months ago we started acquiring the bits and
pieces for these stations, and this time i decided to make everything
a bit nicer and easier to assemble.
this new litter of beagles will be housed decently: i designed and 3d-printed
a custom enclosure that attaches to the back of the weather station console. thanks
to the odd geometry it was a bit annoying to print but the resulting four dog houses
look good and work really well.
this time i've also decided to 'design for manufacturability'
(bwuahaha - translate: i wanted less messy manual soldering and
no connector butchery). this meant switching to a different pic
microprocessor, an 8-pin PIC16F18313, and making a printed circuit
board with keyed connectors to make everything a bit more fool-resistant.
the 16F18313 is a little powerhouse, and i found it amazing how much functionality microchip
crammed into this chip (datasheet for the 16F18313: 471 pages. 16F88: 228). at au$1.31 it's
also much cheaper than the older PIC16F88 i used for the first two stations, and thanks
to freely reassignable pin functions it's much easier to route a single-layer pcb
for that processor.
but getting it to actually work was immensely painful: none of my infrastructure would deal
with this fairly recent chip. my version of xc8 wouldn't compile for it, pk2cmd would not
program it (nor would mplabx talk to my pickit2). lots of swearing and fiddling later i've
got a working PK2DeviceFile.dat for that chip, and proceeded with the pcb making.
after a little time with eagle (and a brief detour to build a small drill press
for drilling the circuit boards) i made these four boards in the most pedestrian fashion
possible (read: using the toner transfer method). soldering on the smt connectors
was easy, using solder paste. and everything did work the first time round :-)
in about a month the four stations will get installed on fraser island and i'll post
an update when they're live.
you can find the updated code for the new pic and the board design (in eagle format
as well as printable image) at https://github.com/az143/davis_weather.
[ published on Sun 04.11.2018 12:21
| filed in mystuff
| tagged fraser_island, weather, fido, beagleboneblack, pic16f18313