text: #ifndef ION_BATTERY_H
  #define ION_BATTERY_H
  
  #include <stdint.h>
  /*
   *
   * RAIN = External input impedance should be <= to
   * (k-0.5)/(fADC * CADC * ln(2^(n+2)) - RADC
   *
   * n = resolution = 12
   * k = number of sampling periods
   */
  
  
  namespace Ion {
  namespace Battery {
  
  bool isCharging();
  
  enum class Charge : uint8_t {
    EMPTY = 0,
    LOW = 1,
    SOMEWHERE_INBETWEEN = 2,
    FULL = 3
  };
  Charge level();
  
  float voltage();
  
  }
  }
  
  #endif
  