following up on an earlier post, here are a few more reasons why 3d printers are both cool toys and useful tools.

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).

 staubi-adapter in petg

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.

 broken door catch 3dp fixery uppery to the rescue 3dp fixery uppery done new heatbed

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 eurong.

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.

 second weatherstation for fraser second weatherstation for fraser second weatherstation for fraser second weatherstation at eurong

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.

 bbb mount in progress bbb mount davis second test bbb mount davis second test bbb mount davis second test bbb mount davis second test bbb mount davis second test

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 :-)

 beagle notdavis pcb before etching bbb notdavis boards bbb notdavis board testfit

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 | ]

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