Why Use A Sensor When A Pseudo-Sensor Will Do?

August 28, 2024 by Lewin Day 30 Comments

Usually, when you need to sense something in a project, the answers are straightforward. Want to sense air temperature? There’s a sensor for that. Particulate content in the air? There’s a sensor for that, too. Someone sneaking up on you? Get yourself some passive infrared sensors (PIRs) and maybe a smart camera just to be sure.

But sometimes you can be sneaky instead, saving the cost of a sensor by using alternative techniques. Perhaps there’s a way to use the hardware you already have to determine what you need. Maybe you can use statistical methods to calculate the quantity you’re looking for from other measurements.

Today, we’ll examine a great example of a “pseudo-sensor” build in an existing commercial device, and examine how these techniques are often put to good use in industry.

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DIY Tiny Dovetail Cube Needs DIY Dovetail Cutter

October 10, 2019 by Donald Papp 4 Comments

Dovetail cutter, made from a 5 mm drill rod.

There’s a trinket called a dovetail cube, and [mitxela] thought it would make a fine birthday present. As you can see from the image, he was successful in creating a tiny version out of aluminum and brass. That’s not to say there weren’t challenges in the process, and doing it [mitxela] style means:

Make it tiny! 15 mm sides ought to do it.
Don’t have a tiny dovetail bit on hand, so make that as well.
Of course, do it all without CNC in free-machining style.
Whoops the brass stock is smaller than expected, so find a clever solution.
That birthday? It’s tomorrow, by the way.

The project was a success, and a few small learning experiences presented themselves. One is that the shape of a dovetail plays tricks on the human eye. Geometrically speaking, the two halves are even but it seems as though one side is slightly larger than the other. [mitxela] says that if he were to do it again, he’d make the aluminum side slightly larger to compensate for this visual effect. Also, deburring with a knife edge on such a small piece flattened the edges ever so slightly, causing the fit to appear less precise than it actually is.

Still, it was a success and a learning experience. Need more evidence that [mitxela] thrives on challenge? Take a look at his incredible vector game console project.