Protocol Buffer (nanopb) integration (#108)

.travis.yml

@@ -9,7 +9,8 @@ cache:
         - "~/.platformio"
 
 env:
-    - PLATFORMIO_CI_SRC=test
+    - PLATFORMIO_CI_SRC=test/TheThingsNetwork.ino
+    - PLATFORMIO_CI_SRC=test/TheThingsMessage.ino
 
 install:
     - pip install -U platformio

Makefile

@@ -0,0 +1,6 @@
+PROTOC = $(NANOPB)/generator-bin/protoc --proto_path=src/api --nanopb_out="-v:src"
+
+.PHONY: proto
+
+proto:
+	$(PROTOC) src/api/*.proto

README.md

@@ -13,7 +13,9 @@ This is an [Arduino Library](https://www.arduino.cc/en/Guide/Libraries) for Ardu
 ## Documentation
 
 * [The Things Network Documentation / Arduino](https://www.thethingsnetwork.org/docs/arduino/)
-* [API Reference](API.md)
+* API References:
+    * [TheThingsNetwork](docs/TheThingsNetwork.md)
+    * [TheThingsMessage](docs/TheThingsMessage.md)
 
 ## Examples
 

docs/TheThingsMessage.md

@@ -0,0 +1,61 @@
+# API Reference
+The `TheThingsMessage` class provides structs for sensor and application data you can encode and decode as bytes.
+
+## Class: TheThingsMessage
+
+```c
+#include <TheThingsMessage.h>
+```
+
+## Type: sensordata_t
+
+Create a struct of this type using `api_SensorData_init_default` as defaults.
+
+```c
+sensordata_t data = api_SensorData_init_default;
+```
+
+Then in your `setup()` function select what fields of the struct should be included when encoding it as bytes:
+
+```c
+data.has_motion = true;
+data.has_water = false;
+data.has_temperature_celcius = true;
+data.has_temperature_fahrenheit = true;
+data.has_humidity = true;
+```
+
+In your `loop()` function read your sensors and set the fields of the struct:
+
+```c
+data.motion = true;
+data.water = 682;
+data.temperature_celcius = 30
+data.temperature_fahrenheit = 86;
+data.humidity = 97;
+```
+
+### Additional analog readings
+
+You can also add other analog readings.
+
+> **TODO:** Document how this works and include in example.
+
+## Method: encodeSensorData
+Encode the message you want to send.
+
+```c
+static void encodeSensorData(sensordata_t *data, byte **buffer, size_t *size);
+```
+
+- `sensordata_t *data`: Structure containing all the message we can send.
+- `const byte **buffer`: Bytes received.
+- `size_t *size`: The number of bytes.
+
+Usage:
+
+```c
+byte *buffer;
+size_t size;
+TheThingsMessage::encodeSensorData(&data, &buffer, &size);
+```

examples/Message/Send/Send.ino

@@ -0,0 +1,54 @@
+#include <TheThingsNetwork.h>
+#include <TheThingsMessage.h>
+
+// Set your AppEUI and AppKey
+const char *appEui = "0000000000000000";
+const char *appKey = "00000000000000000000000000000000";
+
+#define loraSerial Serial1
+#define debugSerial Serial
+
+TheThingsNetwork ttn(loraSerial, debugSerial, /* TTN_FP_EU868 or TTN_FP_US915 */);
+
+sensordata_t data = api_SensorData_init_default;
+
+void setup() {
+  loraSerial.begin(57600);
+  debugSerial.begin(9600);
+
+  // Wait a maximum of 10s for Serial Monitor
+  while (!debugSerial && millis() < 10000);
+
+  debugSerial.println("-- STATUS");
+  ttn.showStatus();
+
+  debugSerial.println("-- JOIN");
+  ttn.join(appEui, appKey);
+
+  // Select what fields to include in the encoded message
+  data.has_motion = true;
+  data.has_water = false;
+  data.has_temperature_celcius = true;
+  data.has_temperature_fahrenheit = true;
+  data.has_humidity = true;
+}
+
+void loop() {
+  debugSerial.println("-- LOOP");
+
+  // Read the sensors
+  data.motion = true;
+  data.water = 682;
+  data.temperature_celcius = 30;
+  data.temperature_fahrenheit = 86;
+  data.humidity = 97;
+
+  // Encode the selected fields of the struct as bytes
+  byte *buffer;
+  size_t size;
+  TheThingsMessage::encodeSensorData(&data, &buffer, &size);
+
+  ttn.sendBytes(buffer, size);
+
+  delay(10000);
+}

keywords.txt

@@ -7,6 +7,7 @@
 #######################################
 
 TheThingsNetwork        KEYWORD1
+TheThingsMessage        KEYWORD1
 
 #######################################
 # Methods and Functions (KEYWORD2)
@@ -20,6 +21,8 @@ personalize             KEYWORD2
 sendBytes               KEYWORD2
 poll                    KEYWORD2
 
+encodeSensorData        KEYWORD2
+
 #######################################
 # Constants (LITERAL1)
 #######################################

src/TheThingsMessage.cpp

@@ -0,0 +1,9 @@
+#include <TheThingsMessage.h>
+
+void TheThingsMessage::encodeSensorData(sensordata_t *data, byte **buffer, size_t *size) {
+  byte message[51];
+  pb_ostream_t sendStream = pb_ostream_from_buffer(message, sizeof(message));
+  pb_encode(&sendStream, api_SensorData_fields, data);
+  *buffer = message;
+  *size = sendStream.bytes_written;
+}

src/TheThingsMessage.h

@@ -0,0 +1,18 @@
+#ifndef _THETHINGSMESSAGE_H_
+#define _THETHINGSMESSAGE_H_
+
+#include <TheThingsNetwork.h>
+#include <pb.h>
+#include <pb_encode.h>
+#include <pb_decode.h>
+#include "sensorData.pb.h"
+
+typedef api_SensorData sensordata_t;
+
+class TheThingsMessage
+{
+  public:
+    static void encodeSensorData(sensordata_t *data, byte **buffer, size_t *size);
+};
+
+#endif

src/api/sensorData.proto

@@ -0,0 +1,13 @@
+syntax = "proto2";
+
+package api;
+
+message SensorData {
+        optional bool motion = 1;
+        optional uint32 water = 2;
+        optional float temperature_celcius = 3;
+        optional float temperature_fahrenheit = 4;
+        optional float humidity = 5;
+
+        repeated uint32 analog_readings = 110;
+}