Servo - August 2016

you need to do to set up a project is give it a name and select your hardware. We selected the Arduino Uno.

The Blynk interface itself evokes The Grid from “Tron,” with its dark background and neon lines. Creating control interfaces with Blynk is as easy as dragging and dropping widgets onto your screen because that is literally what you do. The widgets can take many forms: buttons, sliders, and even a two-axis joystick. You can place display widgets too — everything from simple value displays to gauges.

Once you place a widget, you can click on it to open it up. In the ensuing screen, you can name your widget (something as blandly descriptive as “Servo 1” or as colorful as “Deathclaw;” whatever floats your decimal point), select which pin the device is on, and set a few other parameters that might include the range of your slider (which we set to 180 to account for the limited range of the servo). You can even change the color of the widget.

To start with baby steps, we crafted the simplest controller possible: a humble button. Now, we had to program the Uno. Blynk comes with its own host of Arduino libraries which are freely downloadable from GitHub (linked to from the Blynk website). To make downloading as painless as possible, everything is included in one folder, but that means importation into Arduino needs to be done manually.

Fortunately, both the SparkFun and Blynk websites have step-by-step tutorials on how to do just that. All it entails is navigating to the correct folder on your computer (the Arduino “libraries” folder) and copying the various Blynk folders into it. You’ll need to restart the Arduino IDE (integrated development environment) after feeding it new libraries, but once you do there will be a plethora of Blynk sketches under the Examples tab.

The sketch we were interested in was a demo under the Boards and Shields category specifically for use with the SparkFun Wi-Fi shield. The example code is well commented and surprisingly short. The code requires only a few modifications. Just like with the first demo we used, we had to enter in our Wi-Fi SSID and password. You also need to fill in the Blynk authorization token, and this is where copying and pasting out of your email comes in handy. There’s only one more step, but it’s an important one.

The example code has lines for both the software serial setup and the hardware serial setup. By default, the software serial lines are commented out and the hardware ones are used. We swapped that, and the last detail was to ensure that the RX and TX pins were properly identified in