This seems exactly like the sort of shenanigan that would piss off rather than appease the wood spirits.

I am ratting this out to the Tree Beard

It's like FakeBlock from Arrested development

Or just, you know, walk outside in the fresh air, find a nearby tree, and knock on it...

If an app knocks on a tree and nobody is around…

The knockers are missing solar panels to continuously charge their batteries. So there will be sustained costs to keep them running. And how water-proof are they? Apart from that, it's going to sell like hot cakes.

There are societies where rather than knocking on wood one turns one's head and spits. For example: "Grandad is looking well after his fall, let's hope that doesn't happen again. Ptew!"

Looking for this in app form.

I'd only buy this if it included a subscription-based AI upsell to predict and adapt to my adjusting superstition needs over time

Knocking on wood was about knocking on unpainted wood, so that you have actual direct physical contact with wood. Remote knocking seems to go in the other direction...

Found this other experiment, part of the same series "Machines Responding to Superstitions".

https://www.dezeen.com/2023/10/31/kinky-kashayam-portable-bl...

Though it seems less like machine response than humans integrating technology into superstitious belief.