AWS SDK<\/a>. Yet the solution was right there….within the SDK. All that had\u00a0to be done was to adapt one of the currently supported micro-controller APIs for use with the ESP8266. After reviewing the APIs offered, the one that had the most in common with the ESP8266 was the Spark Core API.<\/p>\nMy first step was to build and test the sample code for the Spark Core (now known as “Particle”). Fortunately, I had a Spark Core device available for this purpose. While there were a few issues with the SDK library which caused the compile process to fail, it did not take long to get\u00a0working Spark Core\/AWS sample application up and running. Code changes included:<\/p>\n
AWSClient2.cpp \r\nChange: Declarations missing for AWS_DATE_LEN2, AWS_TIME_LEN2 and HASH_HEX_LEN2\r\n\r\nAmazonDynamoDBClient.h\r\nChange: Added \"MinimalList<MinimalString > SS;\" to the class \"AttributeValue\"\r\n<\/pre>\nAfter correcting the SDK code, the compile completed successful. And the subsequent\u00a0testing on\u00a0my device\u00a0confirmed the functionality of the API, interfacing flawlessly with AWS.<\/p>\n
The next step was to compile this SDK code with the Arduino IDE for ESP8266.<\/p>\n
Since both the Spark Core and the Arduino IDE for ESP8266 used the sketch\/library model, the structure of the API did not have to be revised. The device specific library code was put in the \u00a0Esp8266AWSImplementations.h\/.cpp files.<\/p>\n
The most significant thing missing from the ESP8266 base library was a time server. The function “updateCurTime()” was added to the\u00a0Esp8266AWSImplementations.cpp file to fill that void. That function attempts to retrieve the current time in JSON format from a yahoo timeserver. While the timeserver URL works properly from a web browser, an error is returned from the ESP8266 “http GET” request. But, fortunately, the http error response includes the current GMT time. Since that is what is needed for the AWS API, it is simply scraped off the response string and used to build an AWS request.<\/p>\n
I also revised the AWS demo program (designed for\u00a0the Spark Core) to eliminate the need for a switch trigger. Instead of initiating an AWS request from the change in state of a switch, the AWS API interface is tested continuously in the sketch’s loop() function.<\/p>\n
This is what the demo sketch\u00a0does:<\/p>\n
setup()\r\n- connects to your local Wifi and initializes an AWS database client.\r\n- a web server is also started, but is not used for this demo sketch\r\n\u00a0\r\nloop()\r\n- first gets the current RGB values from a dynamoDB table\r\n- then sets the dynamoDB table RGB values to an increment of the value from the 'get'<\/pre>\n
![\"\"](\"http:\/\/internetofhomethings.com\/homethings\/wp-content\/uploads\/2015\/08\/cloud_computing_1439393768-300x238.png\")
<\/p>\n![\"\"](\"http:\/\/internetofhomethings.com\/homethings\/wp-content\/uploads\/2015\/08\/IoT_1439408875-300x199.jpg\")
<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"