Is there anything more satisfying than building a useful machine from mostly junk? We think not. [ke4mcl] is a big fan of reusing and repurposing things before settling for the recycle bin, and was in the market for a vibratory parts tumbler to quickly clean off old, rusty bits and bobs in the course of repairing old electronics. For just $10, most of which went into a new tube of RTV silicone, [ke4mcl] built their own tumbler and came away with a reusable amplifier setup in the process.
We’ve all seen speaker cones dance, and they are definitely our favorite way to observe non-Newtonian fluids. This old woofer can still move, so it’s got a second life shaking sand and screws around until they’re somewhat shiny. The ideal woofer for this purpose has a rubber surround — that’s the ring that connects the speaker cone to the frame. [ke4mcl]’s foam-surrounded woofer works just as well, though it may not last as long.
After scrounging a container with a screw-top lid that fits the woofer perfectly, [ke4mcl] joined them together with a bead of RTV silicone. Since there weren’t any amplifiers lying around, [ke4mcl] spent a few bucks on a class D amplifier board and found a spare laptop brick to power it. An old phone with a tone generator app gets the sand churning with a friendly sine wave, which you can see in the videos after the break.
We think it’s particularly nice to keep things like fire extinguishers out of the landfill. If you don’t need a parts tumbler, why not use one to make your own refillable, re-pressurizable solvent container?