Put two of these cards next to eachother, and they won't read. Put them in an aluminium card case, and they won't read. Move more than about 5 cm away from the card and it won't read.

There are numerous ways around this problem. It shouldn't stop people from using the technology.

n/t

When you overwrite data with a known set of data, it becomes much easier to recover. It's just a problem of signal analysis. Check out the Gutmann Method for more details on how this would work.

running some software that writes 0s to the drive

That seems unwise. You're not really wiping the drive, just making it harder to read. Most modern wipe software overlays the drive 7 times with random data.

Or maybe go with van der graaf generators instead.

This is a TERRIBLE source of renewable energy. Lightning is a pulsed power source, where our demands are essentially steady. Lightning is caused either by wind or solar wind (charged particles accumulating in the atmosphere), so why not pick that up directly? We have wind turbines and solar cells. These are far more sensible than lightning as a power source.

And for reference, wind power is effectively solar, since wind is cause by uneven absorption of solar radiation, which causes convection currents.

Well, newer than me, anyway.

Just a point to note: tidal power is a waste of time. The power density available from a perfect tidal pool is about 2% of an equivalent solar array. (This assumes the world's highest tides, but only 600W/m^2 available power for half of the day on average).

In terms of land utilization, we should never endorse tidal power.

Where do I find the manual to fix the on-screen avatar?

Waves don't only interfere constructively at one point. They interfere constructively at many points, to varying degrees. What happens when two devices are using mirrored interference points?

Instead of targeting specific devices, what about dividing the landscape into many physical regions, using constructive interference to cover an area rather than a single device. It would be like space-division multiplexing.

My biggest concern with this tech is not transmission from towers to individual devices, but rather the return call. What are the computational requirements for a receiver using this technology?