Ahh, I remember some bluetooth wmbus reader, which could be powered on or off by shaking it. Presented as puzzle to all new coworkers: "Try to turn it on", so e

Ahh, I remember some bluetooth wmbus reader, which could be powered on or off by shaking it. Presented as puzzle to all new coworkers: "Try to turn it on", so each one proceeded to try rotating antenna or case halves (it was cylindrical in shape), pressing in several places, then shaking near ear to see if something was maybe loose inside, which typically turned it on.