IoT OTG with Blynk iOS and Android App and Arduino Library
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Blynk leverages the touch-screen of a smartphone to provide a nice interface to control a board remotely. Blynk consists on two main elements:
Blynk was launched as a successful Kickstarter campaign last February 2015. Blink is the perfect solution for Internet of Thing on-the-go! |
Draw the Interface
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A project is a screen populated with widgets.
When creating a new project, provide the name and select the board. The application generates an authentication token and can even send it by e-mail. |
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To add a widget, select one from the list, name it and assign a pin.
Pins can be digital, analog or virtual. The virtual pins is a smart way to On this example, I've selected a switch button to control the green LED on pin 10 and a slider to control the red LED on PWM mode. |
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Write the Sketch
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The sketch for the board is very compact with an initialisation and a run command.
The authentication token is provided by the app and sent by e-mail. |
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Play!
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Once the the sketch has been uploaded, go back to the app and click on the arrow to launch the project.
The interface provides a feed-back. The button is illuminated when switched on, the slider displays an orange bar. Speed and responsiveness are good, with a ping delay of 200 ms. |
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New release 0.3.0 of the Blynk library brings an History Graph, which can display up to 4 series.
This is especially useful when used with a private server. The way the LED widget is handled has changed. Posting Blynk.virtualWrite(4, HIGH); no longer works. Instead,
Blynk.virtualWrite(4, 1023); is required to turn the LED on.
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Using Blynk for IIoT Projects
Conclusion
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Blynk offers an elegant solution for adding an interface to a project. The iOS and Android applications are very polished and easy to use.
On top of a growing list of boards supported right out-of-the-box with ready-to-use drivers —mostly Arduino, but also Raspberry Pi, Particle Core and ESP8266—, Blynk provides clear instructions to develop a driver for a new board. This is what I've done for the LaunchPad CC3200 using embedXcode: Blynk included it on its mainstream distribution. Up to now, Blynk focuses on displaying data and sending commands. I'd like Blynk to leverage the different sensors —keyboard, light, accelerometer, compass, microphone, camera— and actuators —sound— of my smartphone for a richer experience. |
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As a more elaborate example, a weather station, uses a BMP180 barometer and a DHT22 hydrometer and thermometer.
Each measure is sent through a virtual pin with a refresh rate of 10 seconds. Go though the detailed Weather and Security Station example. Blynk also runs on a local server. Check out the Private IoT with Blynk on Local Server. New boards and widgets are being added at a regular pace. Development is very active. Blynk has recently updated its offer with a pay-as-you-go scheme called Blynk Energy. Basically, creating a new project and using widgets consumes units, which are partially returned when the project is deleted and the widgets removed. Additional units can be purchased from the app.
I like the idea and hope this scheme will help and sustain the development of Blynk with new widgets, like sending a SMS. |
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Pros
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Cons
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Wrap-Up
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Links
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Posted: Jul 25, 2015 — Edited: Mar 31, 2016
