keen-arduino
This library allows you to push events from the Arduino Yun to https://keen.io.
Examples
Example usage of the keen-arduino library can be found in the examples directory.
#include <Bridge.h>
#include <ApiClient.h>
#include <KeenClient.h>
KeenClient keen;
void setup() {
pinMode(13, OUTPUT);
digitalWrite(13, LOW);
Bridge.begin();
digitalWrite(13, HIGH);
Serial.begin(115200);
while (!Serial);
}
void loop() {
keen.setApiVersion(F("3.0"));
keen.setProjectId(F("YOUR_PROJECT_ID"));
keen.setWriteKey(F("YOUR_WRITE_KEY"));
keen.addEvent("motion_detections", "{\"cat\": 1}");
keen.printRequest();
while (keen.available()) {
char c = keen.read();
Serial.print(c);
}
Serial.println();
Serial.flush();
delay(2000);
}Library Reference
The ATmega32U4 microcontroller on the Arduino Yun has very little RAM. As such, the KeenClient API exposes methods that accept char *, String *, and __FlashStringHelper *. The inclusion of __FlashStringHelper * allows users to wrap their string literals in the F() macro, which will in turn store the data in the more plentiful flash memory instead of RAM.
KeenClient()
The Arduino Yun has very limited RAM. Additionally, there are few use cases for which all of the API keys are necessary. Because of this, the constructor does not take any API key parameters, but rather exposes setter methods to set them.
The constructor does, however, set the default API version to 3.0.
void setApiVersion(const __FlashStringHelper *api_version)
void setApiVersion(const String *api_version)
void setApiVersion(const char *api_version)void setProjectId(const __FlashStringHelper *project_id)
void setProjectId(const String *project_id)
void setProjectId(const char *project_id)void setWriteKey(const __FlashStringHelper *write_key)
void setWriteKey(const String *write_key)
void setWriteKey(const char *write_key)void setReadKey(const __FlashStringHelper *read_key)
void setReadKey(const String *read_key)
void setReadKey(const char *read_key)void setMasterKey(const __FlashStringHelper *master_key)
void setMasterKey(const String *master_key)
void setMasterKey(const char *master_key)unsigned int addEvent(const __FlashStringHelper *event_collection, const __FlashStringHelper *event_body)
unsigned int addEvent(const String &event_collection, const String &event_body)
unsigned int addEvent(const char *event_collection, const char *event_body)unsigned int addEvents(const __FlashStringHelper *events)
unsigned int addEvents(const String &events)
unsigned int addEvents(const char *events)Installation
Copy or unzip the contents of keen-arduino to ~/sketchbook/libraries/KeenClient/ and restart the Arduino IDE. The examples directory provides a good starting point.
Upload Certificate Authority
In order to verify the identity of the remote host, https://api.keen.io's root certificate authority must be uploaded to the AR9331 on board the Arduino Yun. Instructions for uploading the root certificate authority can be found here.
Supported Hardware
The keen-arduino library supports the Arduino Yun, as TLS is required to use https://keen.io's API.
Currently, no other Arduino board has the power or the memory to handle the cryptographic functions required by a TLS implementation. The Arduino Yun's TLS implementation makes use of the on board AR9331 WIFI/SOC which runs embedded Linux.