MRAA

MRAA

Low Level Skeleton Library for IO Communication on GNU/Linux platforms

C/C++ library with bindings to JavaScript and Python to interface with the I/O on the Intel® Galileo board, Intel® Edison board, and other platforms with a structured and sane API where port names/numbering matches the board that you are on. Use of MRAA does not tie you to specific hardware, with board detection done at runtime, you can create portable code that works across multiple platforms.

• MRAA Github

• MRAA Documentation

• AIO Sensors requiring an ADC value to be read

• I2C Modules using the i2c bus

• SPI Modules using the SPI bus

• GPIO Modules using GPIOs directly

• PWM Modules using a PWM capable GPIO pin

• UART Modules using a serial connection (RX/TX)

Manual Installation, Latest Github Code Version

Yocto

    root@edison:~# git clone https://github.com/intel-iot-devkit/mraa.git
    root@edison:~# mkdir mraa/build && cd $_
    root@edison:~# cmake ..
    root@edison:~# make
    root@edison:~# make install
    root@edison:~# nano /etc/ld.so.conf
    /usr/local/lib/i386-linux-gnu/
    root@edison:~# ldconfig
    root@edison:~# ldconfig -p | grep mraa
    root@edison:~# export PYTHONPATH=$PYTHONPATH:$(dirname $(find /usr/local -name mraa.py))
    root@edison:~# nano ~/.bashrc
    export PYTHONPATH=$PYTHONPATH:$(dirname $(find /usr/local -name mraa.py))

Ubilinux

    root@ubilinux:~# apt-get update
    root@ubilinux:~# apt-cache search pcre
    root@ubilinux:~# apt-get install libpcre3-dev
    root@ubilinux:~# apt-get install git
    root@ubilinux:~# apt-get install cmake
    root@ubilinux:~# apt-get install python-dev
    root@ubilinux:~# apt-get install swig
    root@ubilinux:~# git clone https://github.com/intel-iot-devkit/mraa.git
    root@ubilinux:~# mkdir mraa/build && cd $_
    root@ubilinux:~# cmake .. -DBUILDSWIGNODE=OFF
    root@ubilinux:~# make
    root@ubilinux:~# make install
    root@ubilinux:~# cd
    root@ubilinux:~# nano /etc/ld.so.conf
    /usr/local/lib/i386-linux-gnu/
    root@ubilinux:~# ldconfig
    root@ubilinux:~# ldconfig -p | grep mraa
    root@ubilinux:~# export PYTHONPATH=$PYTHONPATH:$(dirname $(find /usr/local -name mraa.py))
    root@ubilinux:~# nano ~/.bashrc
    export PYTHONPATH=$PYTHONPATH:$(dirname $(find /usr/local -name mraa.py))

Based on Installing libmraa on Ubilinux for Edison

Upgrade via Opkg

root@edison:~# opkg list-installed | grep mraa
mraa - 1.0.0-r0
mraa-dev - 1.0.0-r0
mraa-doc - 1.0.0-r0

root@edison:~# opkg install mraa                                                
Package mraa (1.0.0-r0) installed in root is up to date.                        
root@edison:~#

Hello MRAA

The intent of MRAA is to make it easier for developers and sensor manufacturers to map their sensors & actuators on top of supported hardware and to allow control of low level communication protocol by high level languages & constructs.

Using MRAA and UPM requires to be aware of the versions installed, since there is a version dependency of UPM over MRAA.

To find out know the MRAA version that needs to be installed in order to use UPM, type the following in your edison terminal:

root@edison:~# opkg info upm

Something like this is printed in the screen:

Package: upm                                                                    
Version: 0.5.1-r0                                                               
Depends: libgcc1 (>= 4.9.1), libpython2.7-1.0 (>= 2.7.3), libc6 (>= 2.20), pyth)
Status: unknown ok not-installed                                                
Section: libs                                                                   
Architecture: core2-32                                                          
Maintainer: Poky <[e-mail]>                                        
MD5Sum: eb8bbbf6d30c35a79864955914029134                                        
Size: 25851484                                                                  
Filename: upm_0.5.1-r0_core2-32.ipk                                             
Source: git://github.com/intel-iot-devkit/upm.git;protocol=git;tag=v0.5.1       
Description: Sensor/Actuator repository for Mraa  Sensor/Actuator repository fo.

Package: upm                                                                    
Version: 0.7.0-r0                                                               
Depends: libgcc1 (>= 4.9.1), libpython2.7-1.0 (>= 2.7.3), libc6 (>= 2.20), pyth)
Status: install ok installed                                                    
Section: libs                                                                   
Architecture: core2-32                                                          
Maintainer: Poky <[e-mail]>                                        
MD5Sum: d50038c9eb7d197267a2aa9c4531ad20                                        
Size: 33113334                                                                  
Filename: upm_0.7.0-r0_core2-32.ipk                                             
Source: git://github.com/intel-iot-devkit/upm.git;protocol=git;tag=v0.7.0       
Description: Sensor/Actuator repository for Mraa  Sensor/Actuator repository fo.
Installed-Time: 1465260692                                                      

root@edison:~#

root@edison:~# opkg info mraa                                                              
Package: mraa                                                                              
Version: 0.9.5-r0                                                                          
Depends: libgcc1 (>= 4.9.1), libpython2.7-1.0 (>= 2.7.3), libc6 (>= 2.20), libft4222 (>= 1)
Status: unknown ok not-installed                                                           
Section: libs                                                                              
Architecture: core2-32                                                                     
Maintainer: Poky <[e-mail]>                                                   
MD5Sum: 6eab34356ab6b7561a7221b7bf9ce3c1                                                   
Size: 597286                                                                               
Filename: mraa_0.9.5-r0_core2-32.ipk                                                       
Source: git://github.com/intel-iot-devkit/mraa.git;protocol=git;tag=v0.9.5                 
Description: Low Level Skeleton Library for Communication on Intel platforms  Low          
 Level Skeleton Library for Communication on Intel platforms.                              

Package: mraa                                                                              
Version: 1.0.0-r0                                                                          
Depends: libgcc1 (>= 4.9.1), python-core, libpython2.7-1.0 (>= 2.7.3), libstdc++6 (>= 4.9.)
Status: install ok installed                                                               
Section: libs                                                                              
Architecture: core2-32                                                                     
Maintainer: Poky <[e-mail]>                                                   
MD5Sum: 67acedaafba1fc6bb51def2aa3fb6a67                                                   
Size: 434934                                                                               
Filename: mraa_1.0.0-r0_core2-32.ipk                                                       
Source: git://github.com/intel-iot-devkit/mraa.git;protocol=git;tag=v1.0.0                 
Description: Low Level Skeleton Library for Communication on Intel platforms  Low          
 Level Skeleton Library for Communication on Intel platforms.                              
Installed-Time: 1465260638                                                                 

root@edison:~#

From there you can see that we need to installed at least version 0.7.0 of MRAA. In the same fashion you can check the version of the installed MRAA library.

This basic MRAA example, can be used to verify it is correctly installed and found by the compiler

root@edison:~# cd TheIoTLearningInitiative/Sensors
root@edison:~/TheIoTLearningInitiative/Sensors#

root@edison:~/TheIoTLearningInitiative/Sensors# mkdir IoTDKL
root@edison:~/TheIoTLearningInitiative/Sensors# cd IoTDKL/
root@edison:~/.../IoTDKL#

root@edison:~/.../IoTDKL# nano HelloMRAA.cpp

#include "mraa.h"

int main(int argc, char** argv)
{
    const char* board_name = mraa_get_platform_name();
    int i2c_bus, i, i2c_adapter;
    fprintf(stdout, "hello mraa\n Version: %s\n Running on %s\n", mraa_get_version(), board_name);
    mraa_deinit();
    return MRAA_SUCCESS;
}

How to compile?..let's say you have the code above in a file named HelloMRAA.cpp, inside your edison, now from the Edison terminal type:

root@edison:~/.../IoTDKL# g++ -lmraa HelloMRAA.cpp -o HelloMRAA

now if you run the program typing:

root@edison:~/.../IoTDKL# ./HelloMRAA

you will see something like this:

hello mraa                                                                      
 Version: v1.0.0                                                                
 Running on Intel Edison                                                        
root@edison:~#

root@edison:~/.../IoTDKL# cd
root@edison:~#