Add function to send a single bit (true | false) over the Sigfox network This uses a different SPI transaction (0x0B), and allows to send empty frames for basic applications such as buttons, door opening systems, ... Added a simple example called _SendBoolean_

Let me know if I need to structure this differently to fit with the lib architecture :)

Author: nicolsc

examples/SendBoolean/SendBoolean.ino

@@ -0,0 +1,29 @@
+#include <SigFox.h>
+#define VALUE_TO_SEND 1
+#define DEBUG 1
+void setup() {
+
+  if (DEBUG){
+    Serial.begin(9600);
+    while (!Serial) {};
+  }
+
+  if (!SigFox.begin()) {
+    if (DEBUG){
+      Serial.println("Sigfox module unavailable !");
+    }
+    return;
+  }
+  if (DEBUG){
+    SigFox.debug();
+    Serial.println("ID  = " + SigFox.ID());
+  }
+  delay(100);
+  int ret = SigFox.sendBit(VALUE_TO_SEND);
+  if (DEBUG){
+    Serial.print("Status : ");
+    Serial.println(ret);
+  }
+}
+
+void loop(){}

src/SigFox.cpp

@@ -203,7 +203,48 @@ int SIGFOXClass::send(unsigned char mess[], int len, bool rx)
 
   return sig;
 }
+int SIGFOXClass::sendBit(bool value){
+  int ret;
+  int i = 0;
+  status();
 
+  digitalWrite(chip_select_pin, LOW);
+  delay(1);
+  spi_port.beginTransaction(SPICONFIG);
+
+  spi_port.transfer(0x0B);
+  spi_port.transfer(value ? 1 : 0);
+  spi_port.endTransaction();
+  delay(1);
+  digitalWrite(chip_select_pin, HIGH);
+
+  int timeout = 7000;  //7 seconds
+
+  if (!debugging) {
+    LowPower.attachInterruptWakeup(interrupt_pin, NULL, FALLING);
+    LowPower.sleep(timeout);
+    if (digitalRead(interrupt_pin) == 0) {
+      status();
+      return  statusCode(SIGFOX);
+    }
+  }
+
+  for (i = 0; i < timeout/10; i++)
+  {
+    if (digitalRead(interrupt_pin) == 0) {
+      status();
+      return statusCode(SIGFOX);
+      break;
+    }
+    else {
+      digitalWrite(led_pin, HIGH);
+      delay(50);
+      digitalWrite(led_pin, LOW);
+      delay(50);
+    }
+  }
+  return 99; //default
+}
 int SIGFOXClass::beginPacket() {
   bool ret = (tx_buffer_index == -1);
   tx_buffer_index = 0;

src/SigFox.h

@@ -82,6 +82,12 @@ class SIGFOXClass : public Stream
   template <typename T> inline size_t write(T val) {return write((uint8_t*)&val, sizeof(T));};
   using Print::write;
 
+  /*
+  * Send a single bit (0 | 1) over the Sigfox network
+  * Returns the status code from the Atmel Sigfox chipset
+  **/
+  int sendBit(bool value);
+
   //makes no sense in Sigfox world
   void flush() {};