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Tuesday, August 1, 2017
Thinger.io IoT platform (1): connecting a Raspberry Pi device to the cloud
CONNECTING A RASPBERRY PI DEVICE TO THE CLOUD
- Layout for this exercise:
1 - Setting a Thinger.io account
- Thinger.io is a free and open-source platform for the Internet of Things:
https://thinger.io/
- Thinger.io provides a ready to go scalable cloud infrastructure that can be controlled with an easy to use admin console, or integrated into a business logic with REST API.
- The entire project is open-source and does not depend on any specific hardware, what avoids the need to select a compatible vendor hardware:
- Signing up for a Thinger.io account, a name, email and password must be provided:
2 - Adding a device
- At first no device is connected:
- Adding a device:
- Some parameters must be entered, like Device Id, description and credentials (the last one can be generated either manually or randomly):
- For accessing the Dashboard just click the words "device dashboard". As expected, no data/output is available at this moment:
3 - Connecting Raspberry Pi 3 to Thinger.io
- Going to the Raspberry Pi command line, let's install some updates and dependencies:
- Compiler for C and C++:
- CMake is a cross-platform build system generator:
- libssl-dev package is part of the OpenSSL project's implementation of the SSL and TLS cryptographic protocols for secure communication over the Internet, containing development libraries, header files, and man pages for libssl and libcrypto:
- Finally, downloading the thinger-io application from GitHub:
- Unzipping:
- Renaming the folder Linux-Client-master to thinger_client:
- The folder contents some files and subfolders:
- Inside src there is the main C++ program of the thinger.io application:
- Editing:
- The library thinger/thinger.h allows to connect the Raspberry Pi to the thinger.io IoT Platform:
- These 3 parameters must be introduced from the thinger.io account creation at point 2 (Adding a device) of this exercise:
- Eventually, the main.cpp file is like this:
- Let's notice that this application simply adds two numbers and outputs the result:
- pson is a variable type that can contain booleans, numbers, floats, strings, or even structured information like in a json document.
- The operator = defines a function that has both input and output. In this case the function takes two different pson parameters. One for input data and another one for output data.
- The pson structure can store values with keys, like any json document. The result provides a value in sum key, that it is translated to json when accessed them from the API.
- Going back one level into the folder path, there is the script run.sh:
- Giving execution permissions to run.sh:
- Running the script, finally the connection between the Raspberry Pi device/application and the Thinger.io IoT platform is successful:
4 - Testing and running the application
- After performing previous steps, now the connected device whitelist_rbpi is found at the Console Dashboard:
- Clicking View API two values can be introduced, and clicking Run the sum of the two numbers is displayed:
- Clicking Show query displays the REST API calls done by the console while interacting with the device. These calls can be used and integrated in other programs, like clients in .NET, PHP, Node.JS, C++, C, bash, ...:
Friday, July 14, 2017
8 - Raspberry Pi and PIR (Passive Infrared): motion detection and notification to Gmail
RASPBERRY PI AND PIR (PASSIVE INFRARED) MOTION DETECTION AND NOTIFICATION TO GMAIL
- Layout for this exercise:
1 - Introduction
- The goal of this exercise is to use a Raspberry Pi board with a Passive Infrared (PIR) motion detector to sense movement of people, animals, or other objects, and send an email notification when an intruder is detected.
- A PIR sensor is an electronic device that measures infrared light radiating from objects in its field of view.
- PIR sensors are commonly used in burglar alarms and automatically-activated lighting systems.
- Further information about PIR sensors:
https://learn.adafruit.com/pir-passive-infrared-proximity-motion-sensor/how-pirs-work
https://en.wikipedia.org/wiki/Passive_infrared_sensor
2 - Schematics
- The PIR sensor has got 3 pins that are connected to the Raspberry Pi board in this way:
- VCC = pin4 (5 V)
- GND = pin34 (GND)
- Sensor = pin11 / GPIO17
- Also, there is a red LED connected to the pin13 / GPIO27 and pin9 (GND) that blinks after detecting movement:
3 - Code
- This is the Python code used in this exercise:
- Let's analyze the code.
- First, some Python libraries are imported for the email notification:
- The pins are assigned to the sensor (in) and the red LED (out) according to the previously explained schematics:
- The PIR sensor is initially set to 0, and then takes its value from the PIR sensor input. When the status changes to 1, the subsequent actions are performed:
- Immediately a notification email is sent. For that purpose some data must be introduced in the code, for instance the email account and password (blurred in the next picture), and the message to be sent:
- Also, when the variable 'status' takes the value 1 (movement is detected) a message is printed on the screen and the red LED starts to blink constantly:
4 - Running and testing the program
- When the program is run and the PIR sensor detects some movement a message is printed (the number 1 corresponds to the value of the variable 'status') and an email is sent:
- Testing the circuit and the code in this video:
7 - Raspberry Pi and Sense HAT (IV): colors with 8x8 RGB LED matrix
RASPBERRY PI AND SENSE HAT (IV): 8x8 RGB LED matrix
- Layout for this exercise:
- Sense HAT includes a 8×8 RGB LED matrix that is available to program for displaying different color effects
1 - Scrolling time and date in the RGB LED matrix
- This Python program uses color red (255,0,0) for the time and color blue (0,0,255) for the date:
- Giving execution permissions:
- Running the program:
- The output can be seen in this video:
https://www.dropbox.com/s/6osa24003h11moj/Video%20Jun%2028%2C%2010%2005%2009%20AM.mov?dl=0
2 - Rainbow
- Program for displaying the 7 colors of the rainbow:
- Giving execution permissions:
- Running the Python program:
6 - Raspberry Pi and Sense HAT (III): working with the Magnetometer
RASPBERRY PI AND SENSE HAT(III): WORKING WITH THE MAGNETOMETER
- Layout for this exercise:
1 - Introduction
- A magnetometer is an instrument that measures magnetism, either magnetization of magnetic material like a ferromagnet, or the direction, strength, or the relative change of a magnetic field at a particular location.
- A compass is a simple example of a magnetometer, one that measures the direction of an ambient magnetic field.
https://en.wikipedia.org/wiki/Magnetometer
2 - Magnetic North
- The function get_compass() gets the direction of North from the magnetometer in degrees. On the other hand, the function get_compass_raw() gets the raw XYZ axis magnetometer data:
- Giving execution permissions:
- Running the program:
2 - Sensing a magnet
- The function get_compass_raw() detects the presence of a magnet. For instance when the reading for the Z axis is higher than an established limit, turning the LED matrix with red light (255,0,0) every 0.1 second:
- Giving execution permissions:
- Running the program when a magnet is getting closer vertically to the Sense Hat module:
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