How about a "warm wallet" that allows you to only send transactions to your hot wallet on demand, but not to anywhere else?
Please explain how exactly would you do that with Arduino Nano.
All I found in project hub page is Bitcoin Price Updates using Arduino Uno, and much more complex vending machine project.
The idea is fairly straight forward, all you need is the code to sign a transaction and (separately) broadcast it which is freely available online and a little bit of logic to hook to the button.
You can hardcode your keys and target address into the code (just make sure that code is not shared anywhere) and just hook up the broadcasting functionality to a physical button. A led (or some other output) would be good to help you confirm the device did what you expected.
You can break this down into phases:
1. Sign the transactions offline on your PC or wallet, but don't broadcast them. Instead, just copy a small bunch of them to the device where they just queue up and wait to be broadcast when the button is sent and light up a green led. This allows you to skip the signing part for now while getting something working quickly. Of course, it's tedious to "refill" and is limited to the number of transactions you prepared.
2. Add signing to the device, so that it signs then broadcasts a fixed amount with each push.
3. Add more fancy logic to set the amount. Either pick from presets by pushing multiple buttons or longer push, or even control a number with multiple buttons and an 8-seg screen.
