String allowBatteryAccess(){
if(currentMillis-startMillis>(1000*120)){ //if 2 minutes of time has elapsed

digitalWrite(allowBattery, HIGH);

return "Your device has started to charge. Keep Peddling";

}

return " "

}

/* Sallie and Sasha charger programming

*/

// include the library code:
#include <Wire.h>
#include <Adafruit_MCP23017.h>
#include <Adafruit_RGBLCDShield.h>

//PinValues we need to change these
int motorVoltagePin= A0; // voltage output from motor just for fun
int batteryVoltagePin= A1; //voltage of battery that give percent charge
int relayOut=23; //for automatically pressing start button on charger
int allowBattery=24; //for allowing current through the charger

//variables
unsigned long startMillis = 0;  
unsigned long currentMillis = 0;  
int on = 0;
boolean started = false;
float motorVoltageValue=0;
float batteryPercent=0;
float batteryVoltage=0;

//constants
const float referenceVolts = 5;
const float R1 = 3900; // value for a maximum voltage of 30 volts
const float R2 = 1000;
const float RB1 = 2200; // value for a maximum voltage of 15 volts
const float RB2 = 1000;
const float resistorFactorA = 1023.0 / (R2/(R1 + R2));  
const float resistorFactorB = 1023.0 / (RB2/(RB1 + RB2)); 


void setup(){
   Serial.begin(9600);
}

void loop(){
  while(!started){
    startCharger();
    startMillis = millis();
  }
  Serial.println("You've Started the Charging");
  Serial.println("The voltage you are generating is this:");
  
  Serial.println("The battery is charged this many %");
  Serial.println(batteryVoltagePercent());
  Serial.println(allowBatteryAccess());
}

String allowBatteryAccess(){
  if(currentMillis-startMillis>(1000*120)){  //if 2 minutes of time has elapsed
    digitalWrite(allowBattery, HIGH);
    return "Your device has started to charge. Keep Peddling";
  }
  return "";
}

void startCharger(){
  Serial.println("Keep pedaling to start charging");
  motorVoltage();
  if((motorVoltageValue>9) && (on>100)){ //if user has been pedaling at a good speed switch relay on
    digitalWrite(relayOut, HIGH);        //which really is equivalent to pressing Start 
    started=true;                        //on the front panel of the charger
    delay(1000);                         //Hold button for a minute        
  }                                      
  if(motorVoltageValue<2){ //reset the on value if you stop biking, restart the counter
    on=0;
  }
  if(motorVoltageValue>9){ //if you are actually biking at a good speed increase the on count
    on++;
  } 
  digitalWrite(relayOut, LOW);
}

float batteryVoltageRead(){
  int val = analogRead(batteryVoltagePin);  // read the value from the sensor
  float volts = (val / resistorFactorB) * referenceVolts ; // calculate the ratio
   batteryVoltage =volts;  // print the value in volts
  return batteryVoltage;
}

float batteryVoltagePercent(){
  if(batteryVoltage<12){
    batteryPercent=.1;
  }
  if(batteryVoltage<12.5){
    batteryPercent=.2;
  }
  if(batteryVoltage<13){
    batteryPercent=.25;
  }
  if(batteryVoltage<13.5){
    batteryPercent=.6;
  }
  if(batteryVoltage<14){
    batteryPercent=.8;
  }
  if(batteryVoltage<15){
    batteryPercent=1;
  }
}

//say we have a max of 24 volts coming from the motor, we want to scale that down by a factor of 5
//to make sure our arduino can read it (it can read 0 to 5 volts) thus we make a voltage divider where R1 
//is four times as large as R2 so the voltage is 1/5 of the read out of the motor.  We want a small load
//so we make our resistors very large
float motorVoltage(){  
  int val = analogRead(motorVoltagePin);  // read the value from the sensor
  float volts = (val / resistorFactorA) * referenceVolts ; // calculate the ratio
   motorVoltageValue =volts;  // print the value in volts
  return motorVoltageValue;
}