Category Archives: 3D Printing

Adding an Air Filter to a Box Fan

During the wildfires of 2020 I saw many instructions for how to quickly duct-tape air filters to a box fan, to remove smoke from household air. Years before that I was interested in buying a woodworking shop air filter that would remove fine sawdust that otherwise floats in the air for days or weeks.

This post describes my experience making a air-filter-box-fan design, using 3D printed clips instead of duct tape to hold the filter to the fan.

CAUTION: I have no idea how safe it is to clamp an air filter to a box fan. Such a filter may reduce the air flow to the fan’s motor, which might result in overheating and fire. Always supervise the running fan. You’re responsible for your own safety.

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Well Depth Sensing: Mechanical Design

In my previous post, I finished the Web Service that the ESP8266 uses to upload well tank temperatures (and eventually a depth estimate) to a cloud database. In this post, I turn to the mechanical design of the case for the RJ45 jacks for the 1-wire interface.

Since my last post, I’d ordered and received some RJ45 jacks and breakout boards from Sparkfun.  I’m planning to use an RJ45 jack on a half-sized breadboard as the interface between the ESP8266 Thing Dev board and the 1-wire bus.

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Dog Weight Scale Part 12: More 3D Printing

In my previous post, I did a little woodworking on the scale.  In this post, I start designing a 3D printed part that will keep the top of the scale centered on the bottom.

Ever since I measured the center of gravity of the top plywood circle, I’ve been puzzling through how to make sure that center of gravity stays centered on the bottom part of the scale.  Without some sort of connection between the top and bottom plywood circles, the top will inevitably slide over time, messing up all the center of gravity calculations.  On the other hand, if this connection between the top and bottom has much vertical friction, it will take some of the load of the scale, throwing off the weight calculation.

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Dog Weight Scale Part 10: 3D Printing Load Sensor Holders

In my previous post I soldered the weight scale parts to a proto-board.  In this post, I design and 3D-print the part that keeps the Load Sensors from slipping.

The Load Sensor is an oddly-shaped thing that has a few tricky constraints: the T-shaped part in the middle must be free to bend downward (my wooden mounts take care of that), and I don’t want it to slide out of place horizontally or tilt off of its position when I’m putting the top plywood piece on the scale.

I’ve tried a couple ideas – wood holders, washers and bolts – but nothing seemed to work well. So this week I decided to learn how to design and print 3D parts.

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