For a
while now I’ve been thinking about the implantable
NFC tags available at Dangerous
Things. Part of me thinks that it would be incredible to have a usable tag
in my hand that can unlock my phone or tell it to perform a myriad of tasks. Programmable
hardware can be automated similarly to do anything from unlocking doors to keeping a gun from firing.
Months
ago I put an RFID chip in my left ear which was mainly to see how my body would
react to it. I needn’t have worried since the chip uses biocompatible glass and
is made for implantation, in domestic animals. I never got around to
programming any hardware for use with the RFID chips despite having all the
necessary hardware on hand. There’s the obvious problem of placement. An RFID
in my ear is hard to scan unless I’m making a hat only I can wear. RFID can be
used to unlock
an external hard drive but I would have to lay my head on my drive first.
My bony man hand and a huge ring
Having
a chip in my hand puts it in the ideal place to unlock my phone or a door or
wave my hand and unlock that hard drive. The other question though, would I
actually use it? Rather than testing myself by spending $100 plus a piercer to
install it I got this RFID
ring to give hand-located NFC a test drive.
I got
the ring on Monday evening and put it on IMMEDIATELY. This is the biggest ring
I’ve ever worn and I don’t wear a lot of jewelry that doesn’t need a piercing
hole so it’s taking some getting used to. So far, being able to unlock my phone
without a passcode is great but the ring is uncomfortable. It has sharp edges
and is just plain monstrous. I don’t have large hands for a guy and a medium
size ring is shifty on my middle finger. These factors will make me decide on
the implant sooner. I’ll keep updating.
Enough
background.
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A
large galvanized steel corner brace was purchased the other day. It was cut to
obtain two straight braces. It was possible to buy two suitable straight braces
this was less expensive and more importantly the result is two identical pieces
with three holes rather than a straight brace with an even number of holes
which would need a new hole drilled in the center to make the hole-pattern symmetrical
about a central hole. The corner brace was cut twice on a horizontal band saw. The
resulting scrap was a square which was recycled.
Result square scrap
The
straight brace ends were ground on a bench grinder then polished on a belt
sander to make smooth edges which won’t cut skin or abrade bungee. The holes in
the braces were drilled out to 5/16” on a drill press.
Rough ends about to be ground smooth on a bench grinder
Ground ends about to be polished on a belt sander
Drilling the braces to 5/16" on a drill press
The
braces were installed, via the central hole, on the PVC pipes. Two pieces of
5/16” threaded rode were cut to give adequate spacing. The threaded rod ends
were ground and polished the same way as the braces.
Getting a length for the threaded rod
Grinding the threaded rod
Polishing the threaded rod
The
unit was reassembled along with the threaded rods at the front. The back of the
launcher was fitted with the scrap 5/16” threaded rod meaning that nothing on the
48” length of threaded rod was wasted. The front fixture, with the braces, is
not fixed in place and can rotate to block the path of the tennis ball. A screw
hole in the braces and screws into the PVC could eliminate this trouble.
The top threaded rod in place
The front fixture assembled
The
bungee was retensed and the rear strut was bolted in place. A test shot was
fired by pulling the tennis ball hammock back roughly twelve inches and
manually releasing.
Position of the rear support
Video of launch. It ricocheted off a girder and hit my impromptu camerman
To
do:
Affix
front braces
Affix
release mechanism
Build
then mount trigger + handle
Test
Refine
Decorate
Document
Awesome post
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