My WiFi Does Not Work Well in the Basement18 November 2019
If you live in a sufficiently-large house, you probably experienced a weak or non-existant WiFi signal somewhere. Maybe it is in the basement, maybe the garage, or maybe in the kids’ room.
At first blush, this is surprising. The WiFi signal needs to deliver data on just a tiny, tiny amount of energy, which is then amplified by the receiving device. That receiving device does not rely on the WiFi to receive power. It has its own power.
But in some places, even this tiny amount of WiFi signal is not received. Maybe it is absorbed by the walls or the carpet, or maybe it is just too far from the WiFi router.
So, you might ask, why not “turn up the volume” on your WiFi router and just send more power? The reason is that the FCC and other regulators have set a limit to the amount of power a router can send, above which WiFi is not considered safe. This amount varies by country and frequency band, but is approximately 1 Watt of transmission power.
As a result, you see WiFi repeaters, mesh networks and other inventions designed to overcome this limitation.
Now imagine if you actually wanted to deliver power using WiFi. Some have reported harvesting a few microwatts from a WiFi signal, but this is not enough to power anything beyond the most power-efficient devices.
The regulator does not make a big distinction between data delivery and power delivery on the same frequency band, which is why WiFi (and other RF solutions in the same frequency) make for a poor choice for long-range wireless power delivery for consumer applications.
Want data? Use WiFi. Want safe and meaningful power? Use IR.