Thursday, October 09, 2014 Core Evaluation

Last week at the Minnesota Arduino meeting I met the team from  They make a low cost (under $15 in quantity) device that you can program like an Arduino, but it has a full WiFi stack running on it and works with an optional cloud-based service.  They gave me (free) a device to evaluate.  So here is a first look.

The device came in a small box with a half breadboard and a USB connector.  You plug it in and it starts flashing a color that indicates it is "listening for a WiFi login".  If I had a smartphone it would have been easy to give it my WiFi ssid and password, however I did figure out how to give it the credentials using a Windows serial port (putty).  The serial port is not a full unix-like shell, but it got the job done.

Once it got on the local WiFi I went to the web site and "claimed" my device by putting in its device ID (which I also got via the Windows serial interface).  I could then use a web-based IDE to download the standard Arduino "Blink" app.  I also found the NeoPixel library and ported over some of my Moving Rainbow demos. Here is the spark core running one of the rainbow patterns:

It is interesting to note that you can't use many Arduino Libraries alone.  Someone needs to port them.  However I think that most of the common libraries that students would need are there.

What I really liked about the device is that the cloud interface give each device a REST interface.  For example if I put the following into my browser (or use the UNIX curl), I can get my device status:

We can get the status of our device in a JSON format:

   "id": "1234...",
   "name": "dan-test-1",
   "last_app": null,
   "last_heard": "2014-10-10T04:19:08.528Z",
   "connected": true

If you have a smartphone there is a nice app you can use to setup the spark core (wifi and password) and do some basic programming.  However I also want to make sure that I can figure out how to make the spark core work in a teaching setting similar to the CoderDojo meetings.  This is where kids come in with Windows PCs and hook up the Arduino to the USB and fire up the Arduino IDE.  I also think that schools may purchase Chromebooks that they also want to use in the labs.  So I still have a bit more learning to do to see if I can create a full Internet-of-things lab that kids with a low-cost Windows PC can really use.

I like the fact that the system seems pretty open and all the code is on github.  The ARM processor also is a LOT more powerful than the Arduino controller.  The cost is also very low when you consider that a WiFi Arduino shield alone is $90 which is 3x more expensive than the entire device.  The Internet of Things "starter kit" is currently $39.00.  They have another version with many sensors for $99.00 which seems like a good deal.

My initial impressions are that if you have a Linux or Mac and can run node.js from the command line that you should have very few problems.  That is clearly their target developer audience. However many kids don't have access to a smartphone and a $1,000 Mac.  However, having a low cost Windows computer and using an simple Eclipse-like IDE is still something I hope we can have in the future.

I have started to create a simple web-front end and have some basic unit tests running.  I am using Bootstrap 3 and eXist (my favorite NoSQL database) with a few simple XQuery functions to build the URLs. My initial tests allow you to store the device ID and Access codes in a config file and I have a set of functions that convert the JSON responses into pretty HTML pages.  Next I want to be able to change the colors and light patterns using a web form.  I hope that I have something to demo for the Luminarie team at the hackfest a week from Saturday!

Overall rating 5 out of 5 stars!

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