Ingenious Low-Cost Tilt Detection System (2018)
Some considerations: these packages have a very strong adhesive on the back which is hard to remove without damaging the package or surface; they have unique serial numbers (barcoded on newer versions under the bubble packaging) so that they can’t be easily replaced; and the balls are glass, not metal, so they can’t be pushed around by a magnet. It’s overall a pretty ingenious system.<p>Another one is the Tip’n’tell system, which uses fine coloured sand and clear tape to detect tipping in one direction. I once saw one of these affixed to the side of a large autoclave which had been shipped to our university. There’s a whole series of these shipping indicators, for detecting acceleration (shock), temperature (too hot/too cold), and pressure.