[jacquesm]

So, in the true spirit of the HN dismissive comment, but this time I think it really does have its place.

Ultrasonic is DOA, sorry, but that just won't do. It's already a nuisance to have all these switching supplies that mess up your hearing (and some can be surprisingly loud), using it for power delivery is really a non-starter.

There was a company that planned on using ultrasonic for power delivery to smart phones, every engineer with some ultrasonic experience said it wasn't going to work and they just kept going until they - predictably - went out of business.

https://en.wikipedia.org/wiki/SonicEnergy (formerly Ubeam).

Just wishing it exists does not mean it is possible or practical, that's right up there with Theranos (and I think Theranos actually had a better chance of working even though that chance was extremely slim).

There are interesting start-ups around the theme of energy scavenging though, that's a far more realistic but still extremely challenging proposition.

[robotresearcher]

You may have misunderstood. Ultrasound is not being used here to deliver power to these 'sensors'. The devices give off distinctive ultrasound noises when they are bashed by things, like little cymbals. They are not really sensors - they transduce a mechanical input to a high-frequency mechanical output. To be used as a sensor you need a microphone and (typically) an AtoD as well.

Since it's just a little signal, there's very little power in it, so while your pet might hear it, and maybe it'll cause your noise-canceling headphone to squawk, it's not going to have enough energy to hurt anything.

[JK-Swizzle]

Did you read the article? It was not about ultrasonic power delivery. I’d describe it more as tuned ultrasonic bells.

[jacquesm]

Ahh I completely misunderstood the directional flow, thank you for the correction.