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YAVSR: Yet Another Virtual Slide Rule

Google around a bit and you'll find a few slide rule simulators out there. There's Slide (EXE for Windows), JavaSlide (in Java) and The Slide Rule (also in Java).

I figured that the same thing could be done with JavaScript directly in a browser, and with the help of Drag & Drop for Images and Layers I was able to rig up YAVSR. The image is of my Picket N600-ES pocket rule. The N600 seems to be an all time favorite; it's one of the smaller rules that has log log scales, and it allegedly accompanied the astronauts on a few Apollo missions.

The hardest part was scanning the ruler, making sure it was perfectly horizontal, then tweaking, undistorting, redistorting and generally hacking the images to make them fit together and not look like crap. Even then, there's still some distortion and some of the scales are misaligned slightly.

LINK: YAVSR: Yet Another Virtual Slide Rule

INSTRUCTIONS: Just click and drag anywhere on the rule to move the different pieces. To switch to the opposite side of the rule, click the Flip to Other Side button.

COMPATIBILITY: Works with current versions of Mozilla, IE and Firefox.

TECHNICAL NOTE: I commented out line 1197 of wz_dragdrop.js,
"dd.obj.maximizeZ()" so that the images would maintain their original Z-order when clicked.


  • At 12/16/2005 6:10 PM, Ron Charlton said…

    That's a very nice simulation. I used the N600-ES in college ca. 1971-1974. I bought it new from a friend for $5. It's nice to see such a faithful reproduction.


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