This library makes easy to send and receive protocol buffers objects through an arduino stream. Serialize and deserialize is a complex task and it gets harder when you have to do it in a very limited hradware like Arduino.
My intention is just send and receive objects.
First create the messenger (the thing that encapsulates all the complexity)
ProtocolBuffersStream messenger(&Serial);You only need a stream, in this case I used Serial but it is fully compatible with SD, ethernet and any stuff that implements the Stream class (https://www.arduino.cc/en/Reference/Stream)
For this example is used this proto definition:
message Sensor {
required int32 id = 1;
required value float = 2;
}Once you have defined your data model (in this case just a class that contains sensor data) you may want to send it.
Sensor sensor = Sensor_init_zero;
sensor.id = 0xabc
sensor.value = 56.43
bool success = messenger.send(Sensor_fields, &sensor);Thats all, everything is serialized and sent. You also know if everything went fine.
Receiving objects is pretty easy too:
Sensor sensor = Sensor_init_zero;
bool success = messenger.read(Sensor_fields, &sensor);
if (success) {
sensor.id = 0xabc
sensor.value = 56.43
}This library depends on nanopb (https://github.com/nanopb/nanopb). This means that you have to install nanopb library before use Protocol Buffers Stream.
If you are using platformio, just execute:
platformio lib install 431
If you prefer a manual install, you should copy those files into your project from https://github.com/nanopb/nanopb:
pb.h
pb_common.h
pb_decode.h
pb_decode.c
pb_encode.h
pb_encode.c
Check the official documentation (https://developers.google.com/protocol-buffers/) if you dont know how protocol buffers work