Vref = 1100 --mV files = file.list() if file.exists("VrefCal") then print("Vref already calibrated. Great!") file.open("VrefCal", "r") Vref = file.readline() print("VrefValue is set to:", Vref, "mV" ) file.close() else print("VrefCal not found. Vref of ESP chip *not* calibrated. Using default Vref value of 1100 mV") print("It is recommended to calibrate Vref using vrcal.lua and a laboratory power supply.") end