Got some idea about NFC: by sweeping my smartphone over NFC reader tag embedded into this board I can easily switch (reprogram) the crypto engine from, say, Litecoin to Bitcoin, or. any other one coin, assuming I have the capability (the way of reconfigure the FPGA between SH256 and scrypt algorithms by having enough redundancy, i.e. available gates) to easily switch between two or more such cryptoengines. Also, NFC would be an easy way of "taging" between multiple boards forming "a farm".
Humidity sensor would be used as a high/low sensor in environments (such as my hometown settled between three rivers) with high humidity (>90% in summer). Providing the notorious FPGA heating, I assume high humidity would be a trigger for the dehumidifier circuitry/device. FPGA heat in conjunction with high humidity is, as usual, a recipe for disaster in electronics. So, having the humidity sensor is a way to avoid a low dew point which naturally can, and by any "Murphy's law" measure, will, destroy electronics. Burning the FPGA chip is a sort of no concern to me, but having faulty electronics/FPGA which produces bad cryptocurrency, or destroy the already mined ones, or simply waste energy while producing no currency, is a no-no for me.
