I have been using ThingSpeak for a while now and I decided to create my own API for logging IoT readings. The main reason for this is that ThingSpeak require me to manually set it up for each thing I want to log. I think this is tiresome and not as easy as I want it to be. Also I need one api key for each of my connected things. Last, but not least, I don't know how long my data is my data. They may "pull the plug" at any time and have me pay for the service (something I can easily understand).

Due to the above mentions I decided to create my own API for logging IoT. I had some criteria I wanted to follow:

• Use open source
• Easy to use
• No setup before adding a thing
• Easy to read and understandable URLs

When this was written, I have already implemented what I need. I guess I will add more functionality in the future. Here are some of the API calls and an explanation. I will use an outdoor wireless temperature sensor as an example. The sensor is read from a receiver connected to my server. The server will call the API as described below.

I want to log the outside temperature and humidity. To do this I call the API as follows:

{url}/tweet/outside?temperature=23.5&humidity=35

I do this without setting up the "outside thing" first. The system will recognize "outside" as a thing and "temperature" and "humidity" as properties with values automatically. I may add as many property/value pairs as I want.

To read back the latest reading I will use:

{url}/readtweet/outside

This will return the following json (The date is in Norwegian format):

{

    "thing": "outside",
    "lastupdated": "10:23:49 31.07.2014",
    "temperature": "23.5",
    "humidity": "35"

}

If I want to read back only the temperature I will use:

{url}/readtweet/outside/temperature

This will return the single value 23.5

Maybe I want to read the 2 latest loggings:

{url}/readtweet/outside/temperature/2

This will return the 2 latest readings in json format, like this:

[

    {
        "thing": "outside",
        "date": "2014-07-31 10:23:49",
        "temperature": "23.5"
    },
    {
        "thing": "outside",
        "date": "2014-07-31 09:57:25",
        "temperature": "23.2"
    }

]

I have also implemented triggers and charts in this API, but more of this later.