Make SIM unlock explicit

Author: sebromero

examples/SendSMS/SendSMS.ino

@@ -15,10 +15,6 @@
  */
 #include "ArduinoCellular.h"
 
-const char apn[]      = "internet";
-const char gprsUser[] = "";
-const char gprsPass[] = "";
-
 ArduinoCellular cellular = ArduinoCellular();
 
 void setup(){
@@ -29,8 +25,13 @@ void setup(){
     cellular.begin();
     String pinCode = "1234"; // If your SIM card has a PIN code, specify it here
 
+    if(pinCode.length() > 0 && !cellular.unlockSIM(pinCode)){
+        Serial.println("Failed to unlock SIM card.");
+        while(true); // Stop here
+    }
+
     Serial.println("Connecting to network...");
-    cellular.connect(apn, gprsUser, gprsPass, pinCode);
+    cellular.connect(); // APN settings are not required for sending SMS
 
     Serial.println("Sending SMS...");
     cellular.sendSMS("<INSERT_NUMBER_HERE>", "bleep bleep");

src/ArduinoCellular.cpp

@@ -202,11 +202,11 @@ SimStatus ArduinoCellular::getSimStatus(){
     }
 }
 
-bool ArduinoCellular::unlockSIM(const char * pin){
+bool ArduinoCellular::unlockSIM(String pin){
     if(this->debugStream != nullptr){
         this->debugStream->println("Unlocking SIM...");
     }
-    return modem.simUnlock(pin); 
+    return modem.simUnlock(pin.c_str()); 
 }
 
 bool ArduinoCellular::awaitNetworkRegistration(){

src/ArduinoCellular.h

@@ -94,6 +94,13 @@ class ArduinoCellular {
          */
         void begin();
 
+        /**
+         * @brief Unlocks the SIM card using the specified PIN.
+         * @param pin The SIM card PIN.
+         * @return True if the SIM card is unlocked, false otherwise.
+         */
+        bool unlockSIM(String pin);
+
         /**
          * @brief Registers with the cellular network and connects to the Internet
          * if the APN, GPRS username, and GPRS password are provided.
@@ -237,13 +244,6 @@ class ArduinoCellular {
          */
         SimStatus getSimStatus();
 
-        /**
-         * @brief Unlocks the SIM card using the specified PIN.
-         * @param pin The SIM card PIN.
-         * @return True if the SIM card is unlocked, false otherwise.
-         */
-        bool unlockSIM(const char * pin);
-
         /**
          * @brief Waits for network registration. (Blocking call)
          * @return True if the network registration is successful, false otherwise.