CapacitanceMeter.ino

// See http://arduino.cc/en/Tutorial/CapacitanceMeter
#include <ShiftLCD.h>
#include <stdlib.h>
ShiftLCD lcd(4, 2, 3);

const int DISCHARGE_PIN = 5;
const int CHARGE_PIN = 6;
const int R_VALUE = 100;

void setup()
{
  String output = capacitance_reading(103, "uF"); // "0.01uF"
  
  lcd.begin(16, 2);
  lcd.print(output);
}

String capacitance_reading(int C_VALUE, char *c_units)
{
  String s_capacitance = String(C_VALUE).substring(0, 2);
  String s_power = String(C_VALUE).substring(2, 3);
  
  char c_capacitance[s_capacitance.length() + 1];
  char c_power[s_power.length() + 1];
  
  s_capacitance.toCharArray(c_capacitance, s_capacitance.length() + 1);
  s_power.toCharArray(c_power, s_power.length() + 1);
  
  int i_capacitance = atoi(c_capacitance);
  int i_power = atoi(c_power);
  
  float f_capacitance = i_capacitance * pow(10, -1 * i_power);
  char c_value[s_capacitance.length()];
  
  int float_precision = i_power > 0 ? i_power - 1 : i_power;
  int float_min_width = s_capacitance.length() - 1;
  
  dtostrf(f_capacitance, float_min_width, float_precision, c_value);
  
  String s_output = c_value;
  s_output += c_units;
  
  return s_output;
}

void loop()
{
  
}