Ask HN: How do I get started with the physical world?

[Use]

Some servers are connected to technology that is more capable than general computers for a specific use case, such as [1] radios or [2] lava lamps.

[1] https://www.random.org/faq/#Q1.3

"No. It's not just the software you'd need, but also three radios (or one, at any rate), which must be carefully adjusted to pick up atmospheric noise at the right volume. It's not completely trivial to set up."

[2] https://www.cloudflare.com/learning/ssl/lava-lamp-encryption/

"To produce the unpredictable, chaotic data necessary for strong encryption, a computer must have a source of random data. The 'real world' turns out to be a great source for randomness, because events in the physical world are unpredictable."

The examples listed above are for generating true random numbers, but I believe computers' connections to the physical world isn't just limited to that! What should I know before getting started with these kinds of things? Have you built an application that uses similar external technology?

[h2odragon]

computer's sensors are influenced by the real world, but the represent it with a limited, low fidelity version of "what responses they can give"

... like floating point numbers can represent a broad range of values, but only a specific, limited number of exact quantities within that range.

It is a limitation that causes no end of trouble until understood.