[1] https://shop.fsf.org/storage-devices/neug-usb-true-random-nu...
Otherwise I’d be happier using a similarly priced USB tool that is at least designed for the job such as the ChaosKey which is also open hardware and firmware and has a Linux driver in tree
http://www.rambus.com/wp-content/uploads/2015/08/Intel_TRNG_...
Edit: Just curious: are people downvoting because they disagree with my proposed spelling, or because they don't like the correction? Please let me know so I can integrate this knowledge into future comments.
https://www.sparkfun.com/products/14209 https://www.newegg.com/Product/Product.aspx?Item=0EF-005S-00...
Hardware fails. Can you reliably detect that? The board you linked to cannot at all. Most HWRNGs can, but only partially.
It's probably a fun project to try, but I'd be wary of using it for cryptography if only because we have other better methods.
I collected a bunch of links a while ago. Here they are, I don't know if these are still working or interesting, but they might be useful: https://news.ycombinator.com/item?id=6060636
An old project of mine:
It was good enough to use for a financial application when whitened / XORed with system sources.