Gaming tables

Spontaneous Projects is a chronicle of all of my projects, a reference for me, and a way to prevent others from making the same mistakes. 

The commercial options for gaming tables are pretty expensive, but I was able to find a second hand coffee table that looked convertible. The main requirements were a padded lower cavity, and the ability to be used as a normal coffee table. Hopefully I can do a similar thing with a full size table at some point. 

• First remove the glass and measure the base for the gaming surface. Cut a piece to fit out of fairly think MDF, 16+mm prevents bowing. 
• Cut support rails for the base, MDF offcuts work fine. If you can remove the glass supports so that you can drop the base in from the above, do so. 
• Attach the supports to the inside of the frame, ensuring that they are level. 
• Drop in the base and cut a piece of neoprene or felt to fit. Neoprene is a much nicer finish, and is water proof as well, so I recommend it if you can. 
• To cover the holes in the frame I also added side bumpers, just gluing on a small strip of neoprene black side out so it disappears

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Disc Dyeing

I've recently taken up disc golf, and decided to customise a few discs now that I have some decent plastic that will take dye properly.

Materials

Discs - In this case I had a few premiums, DD biofuzion and Discraft Ti and I did a few practice runs on DD classic blend
Dye - iDye Poly, in red and black. each mixed in 500ml of water and kept in mason or equivalent jars between uses
Contact self adhesive covering
Acetone - for wiping stamps
Stencils
Exacto knife & cutting board
Light table
a pot large enough to fit the discs.

The process

Print the stencils, prepare a piece of contact that is at least 5cm more than the diameter of the disc. Either trace the stencil onto the contact, or cut it out directly using the light table.
Remove the areas that you want to dye, and leave the others in place. I'm still working on the best way to keep the geometry for small pieces intact. In this case I cut the contact from the front side, added masking tape over the top, flipped the new mask and removed the pieces to be dyed entirely, then the backing paper from the remaining sections.

The disc can then be lowered onto the contact, placing it in the desired location if possible, a clear bench might assist in this process. Flatten the edges of the contact around the stencil, and make sure to do the edges of the previous stamp as well.

Put the 500ml of dye in the pot, and ensure that there is enough to float the disc in. Heat the dye until it steams slightly then turn it off or down to prevent burning.

Wash the disk and mask to remove any residual glue, and to ensure that there are no air bubbles when you dip the disc. Slowly lower the disc into the pot, and allow it to float there. Readjust it occasionally to check the progress of the dye and to ensure that all areas get dyed properly.

When the dye is as dark as you want, remove the disc and run it under cold water to remove excess dye. Peel the contact off and wash again. I haven't yet found a good way of removing the gunk left behind by the contact.

Ti Buzz, plain green originally, now with a black gecko. It dyed nicely, and looks original, although there were a few areas where the masking leaked and the dye ran. 

BioFuzion Tresspass, grey colour, with a black dyed star destroyer. A lot of runs and issues on this one, but it turned out well anyway. 

The two Classic blend Wardens were dyed mostly for practice, I'd heard that they were unlikely to dye properly, in the case of the red dye on the white warden, it took a lot longer, and the red was still very faded. The black dye went over the blue nicely. Unfortunately I got the stencil backwards and didn't notice...

I'll post again with a progress report when I see how much and how they fade.

Raspberry Pi Car Audio

Spontaneous Projects is a chronicle of all of my projects, a reference for me, and a way to prevent others from making the same mistakes. 

So I finally got myself a couple of Raspberry Pi's, so I'm trying to get my head around what they can do. 

To start off with I'm setting one up to act as an airplay speaker for my iphone, and probably a media server that plays a random selection of music. 

First thoughts

• Using it without the SD card doesn't boot, just a black screen. 
• I've installed Raspian, it's easy enough to set up for WiFi and general display etc. 
• nano and leafpad work well enough as text editors

Setting up audio for the 3.5 jack not the HDMI port

amixer cset numid=3 1 
    3 2 will make it HDMI again. 
testing the output can be conducted through aplay file.wav for any wav files you can find.

Installing Shairplay

I used parts from here and here. 

Shairplay is an airplay emulator, and I've found installing it to be a bit of a pain, lots of older blogs and things, but nothing current.

first up, we need to update the apt-get functions, you'll probably need sudo privileges
apt-get update
apt-get upgrade

then install some basic dev dependencies for Shairplay, some may already be installed, but it can sort that out for itself.
apt-get install libssl-dev libavahi-client-dev libasound2-dev

apt-get install git libao-dev libcrypt-openssl-rsa-perl libio-socket-inet6-perl libwww-perl avahi-utils libmodule-build-perl 

Then install Perl, this might not be required, and can certainly be done later... I'll find out when I reinstall it at some stage.

cd perl-net-sdp perl Build.PL
sudo ./Build
sudo ./Build test
sudo ./Build install
cd ..

Finally we can install shairport

git clone -b 1.0-dev git://github.com/abrasive/shareport.git
cd shairport
./configure
make
make install

You'll be missing a few things, libao, PulseAudio, but they are not essential.

Run it using ./shairport -a 'NameHere'


Some Issues I had:
symptoms, Pi is visible as an Airplay device, but won't connect.
cause: lack of avahi, perl or libao, or some other dependency that is now added in the above code. I think it's the avahi mDNS, as forcing the use of tinysvcmdns causes the same issues. But I think this was caused by the lack of perl-net-sdp...

Mechanical Movements and Ingenious Mechanisms

Spontaneous Projects is a chronicle of all of my projects, a reference for me, and a way to prevent others from making the same mistakes. 
This is a listing of a few pages that I wandered across and felt would be useful for future spontaneous projects.

I was wandering around the internet the other day, looking at crazy gears and the like... something I want to play with a bit more once I get my scroll saw back, but these were linked in the page.

These books are really interesting, out of copyright and should be useful for mechanical art pieces and the like

Five Hundred and Seven Mechanical Movements by Henry T. Brown, published 1868

Ingenious Mechanisms for Designers and Inventors Vol 1 by Franklin D. Jones, Copyright 1930
Vol 2
Vol 3
Vol 4 



The same site that hosts the Ingenious Mechanisms volumes also has a huge variety of docs, including instructions for making band saws, lathes and the like.
It's well worth a look

Spontaneous Etcher

Spontaneous Projects is a chronicle of all of my projects, a reference for me, and a way to prevent others from making the same mistakes.

Hole through a hatchet, masked with packing tape

Last night I was out with a friend, a bladesmith based out of Canberra, and he was discussing the need to place makers marks on blades to make a name for himself, which is easy enough on a fully forged blade using some punches when the blade is malleable. 
He's looking into doing a few cheaper blades, just ground down, so the risks of bending it, and the time consumed make punching inefficient. 

He mentioned Electroetching, using a DC current and some salt water, to remove iron ions from the blade, removing material and resulting in an etched blade. He's done a proof of concept before using a few 9v batteries, but felt that it was too dangerous, given how the batteries heated up. 

 I have a few old laptop chargers lying around, including a 19v, 4.67 A charger, that is unlikely to be all that useful for powering other things. 
So today we made up a new etcher, and tested it on a few blades; an old machete, a stainless cooking knife and a hatchet. 

By masking the area with nail polish, and scratching a design through the polish it is possible to create the design. The remaining area of the blade was protected with packing tape, while the positive electrode was clipped to the blade, and the negative attached to a ball of cotton wool soaked in a mixture of vinegar and salt.

The first design (left) was just a wordmark "Bruce !!!", and worked quite well in about 5 minutes with a heavily salted solution. However the area that was masked with polish was also etched slightly, due to uneven, or insufficient coverage. 

Emboldened we went for a more complex design, the bearded guy below, this was less successful, as the cotton ball had to be moved around to ensure good coverage, and the polish lifted in places. 



We decided to see what shape the process created below the surface with a deeper etch, and how long it would take, so a rectangle was masked out with tape, and a hole made through the machete - minimal heating of the power supply, despite working for over an hour to get through ~2mm of material in a 12x3mm rectangle. This required several cotton balls, a lot of electrolyte solution and a bit of movement to clean out the etched area occasionally. Not something that we'll want to do to blades, but a good proof of concept.

Wanting to make something a bit more practical, and test the process on a different material we tried a hatchet, cleaned up the rust a little, sanded it back, and made a design that will likely be similar to his final one, a Celtic knot, and his initials.

The photo doesn't show a lot of detail here, but the etching wasn't particularly smooth, possibly due to the design in the polish, or too aggressive a process, but it etched, and gave a recognisable mark.

The last thing to test was the behaviour of stainless steel, so a kitchen knife was etched, again the polish layer was a little thin, and we started off with no salt in the solution, but it was too slow.   Increasing the salt content increased the reaction rate, but it was still slower than the steel blades.

End result was promising, but we need to find a better way to mask consistently.

Thoughts:

• Masking needs to be waterproof and possess high resistance
• Masking needs to be held tight to the material
• Timing is important, and will vary for different materials
• A new switch is needed, and a new clamping method is desirable

Ideal masking will be plastic film, cut to shape in bulk, so either a sticker manufacturer, or one of the stamps that you can get at lincraft etc.