Hackaday Podcast 051: Pointing With Your Tongue, C64 Touchpad, USB Killcord, And Audacity Does Everything

Hackaday editors Mike Szczys and Elliot Williams sort through the hacks you might have missed over the past seven days. In FPGA hacking news, there’s a ton of work being done on a newly discovered FPGA dev board. Kristina has a new column on input devices, kicking it off with tongue-actuated controllers. We wax philosophical about what data you need to backup and what you should let go. Plus Audacity is helping tune up CNC machines, copper tape is the prototyper’s friend, and fans of Open should take note of this laptop project.

Take a look at the links below if you want to follow along, and as always tell us what you think about this episode in the comments!

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Get Compressed Air From Falling Water With The Trompe

If you’re like us, understanding the processes and methods of the early Industrial Revolution involved some hand waving. Take the blast furnace, which relies on a steady supply of compressed air to stoke the fire and supply the oxygen needed to smelt iron from ore. How exactly was air compressed before electricity? We assumed it would have been from a set of bellows powered by a water wheel, and of course that method was used, but it turns out there’s another way to get compressed air from water: the trompe.

As [Grady] from Practical Engineering explains in the short video below, the trompe was a clever device used to create a steady supply of high-pressure compressed air. To demonstrate the process, he breaks out his seemingly inexhaustible supply of clear acrylic piping to build a small trompe. The idea is to use water falling around a series of tubes to create a partial vacuum and entrain air bubbles. The bubbles are pulled down a vertical tube by the turbulence of the water, and then enter a horizontal section where the flow evens out. The bubbles rise to the top of the horizontal tube where they are tapped off by another vertical tube, as the degassed water continues into a second vertical section, the height of which determines the pressure of the stored air. It’s ingenious, requiring no power and no moving parts, and scales up well – [Grady] relates a story about one trompe that provided compressed air commercially for mines in Canada.

Need an electricity-free way to pump water instead of air? Check out this hydraulic ram pump that takes its power from the water it pumps.

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