Tag Archives: woodworking

Geometry, Gothic Architecture, Rose Windows, and Christmas Ornaments

(first published on Needhamia.com in 2007)

I find the rose windows of Gothic cathedrals awe-inspiring. From the rigid formalism of Chartres to the flamboyant explosion of Tours, their marriage of geometry, philosophy, and aesthetics with stone and glass is awesome. Built at a time when science and spirit weren’t as divided as today, each window is a statement of the beauty, order, and harmony in the world. Using only a pair of compasses (dividers) and a straight-edge (an unmarked ruler), the Gothic architects created myriad lace-like designs, making stone hang in the air and glass sing.

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Dog Weight Scale Part 13: Load Sensor Mounting and Final Assembly

In my previous post, I designed and printed a Centering Guide to line up the top and bottom pieces of the scale.  In this post, I finish assembling the scale.

Now that I have the Load Sensor Holders that I designed and printed, I drilled mounting holes in the blocks that will hold the Load Sensors.

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Dog Weight Scale Part 11: Routing Counterbore holes

In my previous post, I 3D-printed parts to hold down the Load Sensors. In this post, I fix the counterbored holes that keep the nuts from protruding below the bottom of the bottom piece of plywood.

In the woodworking post, I used a router to cut counterbore holes on the bottom side of the bottom piece of plywood.  These holes hold the nuts that hold the circuit boards.

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Dog Weight Scale Part 5: Center of Gravity and a mounting Fail

In my previous post I described how to calibrate a load sensor. This post shows how to measure center of gravity, and shows a failed attempt to mount the load sensors to the scale.

Now that I’m using 4 load cell amplifiers rather than 1, I can calibrate each load sensor separately.  This in turn will let the Arduino calculate Pippa’s real weight accurately regardless of what part of her bed/scale she’s lying on.

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Dog Weight Scale part 3: the woodworking and assembly

In my previous post I described the electronics of the Dog Bed Weight Scale. In this post, I’m doing the final woodworking and assembly – at least enough assembly to test the thing.

First I needed to design some sort of support for the load sensors.  Because of the design of the sensor – a “T” bar surrounded by a “C” shaped bar – I needed to make blocks that were 1) tall enough to keep the top piece of plywood from resting on or crushing the electronics and 2) cut out to allow the “T bar to bend below the “C” shaped part as weight was added.  You can find plenty of videos of people trying to use load sensors by mounting them on a flat surface; that won’t work.

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Dog Weight Scale, part 1: cutting the circular base

I want to learn how to use Load Sensors to continuously weigh stuff with an Arduino, so I thought it would be fun to continuously weigh our dog, Pippa, while she sleeps in her bed each night.  The project is a little like Nate Seidle’s Beehive scale, but simpler.

The idea is to turn Pippa’s bed into a scale. Pippa’s in fine shape right now, but it’s always good to keep an eye on your dog’s weight, and a custom-made scale is a great way to do it.

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How to Make a Drill Press Table

As multiple woodworkers have mentioned, a drill press as-is is poorly suited to doing woodworking: the cast iron table can transfer grease to the wood; the table is small; the table has limited places to fasten clamps to hold the wood down.

So here I am making a drill press table.

I started with a sketch based on this drill press plan, with an offset waste plug circle from this nice design.  I’ll narrate the project as a “how to” from here on.

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