Designed by Brian, manufactured by lasers: part 2, The Programmer’s Desk Reference

This is a fol­lowup to my pre­vi­ous post, Designed by Brian, Manufactured by Lasers.  That was my “Hello, World” intro­duc­tion project to laser cut­ting: sim­ple coast­ers with etched designs and a coaster-holder.

This sec­ond laser-cut project was designed to have a bit more 3D, using a cou­ple of inter­lock­ing pieces.  I do quite a bit with 3x5 cards (see also: my Hipster PDA posts), so I thought I might try for a 3x5 card-sized easel with a “card” etched with infor­ma­tion use­ful to pro­gram­mers.  I thought this “card” could also be used as a mini clip­board, with the addi­tion of a binder clip.

After play­ing around with the design, I found that what I wanted on the card—an ASCII chart—needed a bit more space than 3x5, so that piece grew a bit.

I did not go with the binder clip idea. I thought the etch­ing would be much deeper and I worry that the clip might mar the ref­er­ence a bit too much.  I made the holes a lit­tle small, but for­tu­nately this design is wood and could be eas­ily filed down.

Seven inter­nets to any­one who can guess (and wasn’t already told by me) what that third col­umn is — the one with the alter­na­tive hex.

The easel itself has a lit­tle extra ref­er­ence that I couldn’t fit on the main ref­er­ence block, namely a hex-to-binary chart. I’m good with doing 0..9 in my head, but I always have prob­lems with the range from B to E — I have to con­vert to dec­i­mal in my head and/or on my fin­gers, then to binary.

The next big project will require some MakerBot pro­to­typ­ing and at least one metal piece in the final build, so I’m going to have to com­pare prices and mate­ri­als between Ponoko and Shapeways.

Posted in: Projects

3 thoughts on “Designed by Brian, manufactured by lasers: part 2, The Programmer’s Desk Reference

  1. I don’t know what the third col­umn is. All I can guess is some alter­nate ascii set. It’s still a hex num­ber, but it some­times doesn’t equal the num­bers before it in dec­i­mal and hex (because it’s +128d (+80h)), but other times it does. And the way it doesn’t or does fol­lows a recur­sive pat­tern.

    I have no idea why though.

      1. Yeah, that high bit (0x80) gets set or not set so that there’s always an odd num­ber of bits in the num­ber. It’s the crap­pi­est form of error-detection out there, but I guess it (mostly) works in sim­ple cases where you only expect on bit in >8 to acci­den­tally tog­gle, like broad­cast cap­tion streams. With dig­i­tal tele­vi­sion, trans­mis­sions are wrap­pered with much bet­ter error han­dling, so it’s kind of moot (and awk­ward) these days to use the par­ity bits.

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