Modifications

Now, we can focus on the main loop.

Now, we can focus on the main loop.

The first step is to send the header if not done yet.

The first step is to send the column header (so we know what are the data) if not done yet.

Then we reads the sensors (as we have tested them, this should not be a surprise). We also capture the time with the function {{fname|millis()}}, so the {{fname|ms}} variable contains the number of milliseconds since the last reset.

Then we reads the sensors (as we have tested them, this should not be a surprise). We also capture the time with the function {{fname|millis()}}, so the {{fname|ms}} variable contains the number of milliseconds since the last reset.

{{fname|packet_str}} is the message to send via radio. It is composed with {{fname|String}} objects and concatenation operations. {{fname|String}} are welcome to transform '''float''' into string representation since most common float to string C standard functions would fail to work properly onto Arduino alike plateforms.

{{fname|packet_str}} is the message to send via radio. It is composed with {{fname|String}} objects and concatenation operations. {{fname|String}} are welcome to transform '''float''' into string representation since most common float to string C standard functions would fail to work properly onto Arduino alike plateforms.

The key function to transform the '''String object''' into a '''C buffer'' is {{fname|packet_str.c_str()}} which offer an access to the underlying array of bytes (exactly what we would need for the radio module library).

The key function to transform the '''String object''' into a '''C buffer'' is {{fname|packet_str.c_str()}} which offer an access to the underlying array of bytes (exactly what the radio module library would need).

 

The remaining of the radio transmission code is almost the same as the RFM69HCW module testing code (except that error messages are remplaced by Blinking LED).

   

   

<syntaxhighlight lang="c">  

<syntaxhighlight lang="c">  

bool header_send = false; // if header has not been send yet...

bool header_send = false;

int16_t packetnum = 0; // packet number increment at each data emission

// packet number increment at each data transmission

void loop() {

void loop() {

     // --- SEND COLUMNS HEADER -------------------

     // --- SEND COLUMNS HEADER -------------------

     // Going to next round

     // Going to next round

}

}

void init_radio_module() {

void init_radio_module() {

   pinMode(RADIO_LED, OUTPUT);     

   pinMode(RADIO_LED, OUTPUT);