The Nikon D3100 is a great camera for the price, the bottom end of Nikon’s DSLR range. Being a bottom-end camera, a few things are missing, like an external power connector. I’m using this camera in a fixed setup for slide scanning. The 1080p live view makes an excellent way to preview slides on an HDMI monitor, but this will drain the battery quickly. One option is to use the Nikon EP-5A, which is basically a battery-like plug for the camera, which then attaches to the Nikon EH-5A power supply. This will run you about about $108 at B&H. A spare battery will run you another $50. None of the third-party batteries available apparently work in the D3100, as Nikon puts some sort of inkjet cartridge-style money-sucking chip inside their batteries. (I’m sure the vast camera accesory factories in China are working to overcome this issue).

It turns out the answer to both these problems is a third-party D3100 battery grip, $20something from Amazon.

The left-hand battery slot in the D3100 will take the $8 third-party batteries, as the camera is happy as long as it can see a Nikon battery when it starts up. I decided to add a barrel type power jack so I can power the camera off a power supply. I suppose it’s possible that all these infidel non-Nikon parts could cause the camera to explode, so don’t try this at home, kids.

The battery grip contains a circuit board that runs the whole width.

I attached the barrel plug to the left-hand (“infidel”) battery slot. In this photo, Green is – and White is +. Most DC power supplies are center-positive, and so I used that scheme here. I picked a spot for the barrel plug that puts it right against the battery slot so it can’t easily pop out. I carefully drilled a hole in the case, squared it off, and hot glued it in.

It works perfectly. You can even remove the genuine battery once the camera is booted.

201_0291.MOV, originally uploaded by metrixcreate.

My clock. It ticks.

It has knobs like a real radio, but yet it plays modern radio stations. There’s no screen yet, but one is coming.

I use an Arduino to connect the switches and selector knob to the computer inside, and it uses mpd (the music player daemon) to tune through a playlist of internet radio stations. Code for that is at github.com/afiler/filko.

Connecting an Apple II keyboard to a computer with USB is surprisingly easy with a Teensy board. The Apple II uses an ASCII keyboard, which means that rather than returning scan codes, it returns a 7-bit ASCII value. This also means you can’t read the state of modifier keys like shift or control independently. The Apple II keyboard in particular doesn’t even support lower-case letters (though I’ve made a bit of a hack for this). They even re-use a couple alpha keys for other characters, so shift-P makes @ and shift-N makes ^. Other late 70s/early 80s home computers like the TRS-80 had a really simple layout like the Apple II’s (though the TRS-80 had all four arrow keys but no Control key). I may have to try out adapting some other weird old home computers as USB keyboards — the C-64 seems like it would be a good shape/size for that.

Arduino (Teensyduino) code is available at https://github.com/afiler/keyduino.

Since Unicode “works” in most places on the internet these days (from webpages to Twitter to IRC in terminal sessions), I like to use all the characters that are available to me, when they make sense — like “99¢” or “-40°”. I decided go to Metrix and laser many of the characters accessible from Alt(Gr) into the keycaps on my MacBook Pro. The keyboard is backlit and lasering the key exposes the clear key underneath, so it turned out quite well. If I’m feeling like there still isn’t enough visual interference on my keyboard, I may decide to laser on the AltGr and Cyrillic characters too.

Duncan and I made tshirts with the “phone company” logo on them (no actual phone company has this logo, but it looks a lot like the logo of some random independent phone company in the 1970s.

They were screen printed, but with a plastic stencil instead of a photo-process “stencil”. I bought a book of polypropylene sheets from Dick Blick (“suitable for water color”, the cover says), and got the stencil cut on the laser cutter at Metrix. They can’t cut vinyl or other chlorine-containing compounds, as deadly chlorine gas will be produced (though in quantities that would probably be more damaging to the laser than to humans), but polypropylene works great.

http://doc.mar.cx/http://www.ieee.org/documents/IEEECopyrightForm.doc

This will give you an HTML version. If you’d like a different output type, insert that type’s extension in front of the URL. For a plain-text version instead, for example,

http://doc.mar.cx/txt/http://www.ieee.org/documents/IEEECopyrightForm.doc.

PDF, HTML, text, CSV, XLS, and DOC output formats are supported on the relevant data types. I’ll soon be adding ImageMagick support to convert from zillions of image formats, and conversions to/from .SHP shapefiles, KML files and other geodata should also be supported soon.

Want to know what input document types are supported? Just try the link. If it works, then that document type is supported. If it doesn’t work, then that document type isn’t supported.

More finger feature suggestions are welcome!

I made a monitor stand out of black gas pipe and fittings, compression tees, and an adapter bracket.

The compression tees (as in pipe fittings, not clothing) were an awesome find. They have rubber gaskets inside that made a surprisingly tight connection once the end caps are screwed down.

The galvanized metal fitting is a bracket made for using metal pipes for things like mounting rails and chin-up bars. The holes are 38mm apart, as opposed to 100mm on the standard VESA mount, so I made an adapter bracket. I made the adapter out of 6mm birch on the laser cutter at Metrix Create:Space though it would be easy enough to make at home — but lasering’s just so easy! I even countersunk screw holes using the laser.

I’m really impressed with the stability of the stand. I had been worried I’d need to add clamps under the compression tees to make sure they wouldn’t slip, but it turns out they’re far more solid than expected.

If I ever go completely insane and decide I need more monitors, I’m thinking I could make an X-Y setup, with two vertical bars, on which horizontal bars could be mounted. Each row could still have its height adjusted, plus this would allow an up/down tilt on each monitor.

Total cost for this was about $70, $8 of which was for the (very optional) laser cutting.

The oddball switches are the ones that really interest me, and they’ll be the first ones to disappear from the network. I’ve been told that the TRW Vidar ITS-5 and the Mitel GX5000 switches may be gone from the North American network. To see what might be left, I decided to do some digging, and I’ve come up with a list of the telephone switches (minus remotes) still in use in the North American network. There’s undoubtedly some stale data in this database, and so for rare switches, I think the numbers listed are the upper boundary — the lower boundary may be as low as 0. The list also contains the mystery “Digital Switching System”. There seems to be an awfully large number of them for it to be the North Electric DSS-1, which became the ITT 1210 — maybe it just means “unknown digital switch”?

The picture above of the GTD-5 EAX was shamelessly stolen from the site of a GTD-5 consultant, the only place I could find a picture.

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