Before we actually start building the project itself, let's first quickly talk about Bitcoin, in case you don't know what it is yet.
Bitcoin is a virtual currency that emerged back in 2009. Unlike other virtual currencies that existed up to then, Bitcoin is protected by a global network of computers, all working with the same distributed ledger called the Blockchain, which guarantees every transaction made.
Since then, a lot of people and businesses around the world have started to accept Bitcoin as a way of payment. Bitcoin is also accepted in brick and mortar stores; for example, stores that display the Bitcoin Accepted Here sign:
Of course, Bitcoin is also traded on exchanges, and therefore has a price in USD, and in most of the main currencies. For example, at the time of writing this book, one Bitcoin was worth 417 US dollars.
Therefore, it could be quite interesting and fun to make a project to find out how much Bitcoin is currently worth, using the ESP8266 Wi-Fi chip...