How to choose best LCD for your Linux computer? This is why we made LCD-OLinuXino selection guide


LCD-OLinuXino selection guide will help you to select best solution for your OLinuXino Linux SBC.

Inside we explain the different LCD connectors available in OLinuXino.

What LCD variants are available: 4.3″, 5″, 7″, 10.1″, 15.6″.

What signals are there when the interface is RGB or LVDS on the 40 pin connector.

How we implement plug and play capability with our latest Linux images and LCD driver boards, so you do not have to configure the LCDs, but they are recognized at boot time and all drivers configured.

What are the pro and cons and differences between resistive and capacitive touch screen technologies.

How to enable digital touch interface on A20 boards.

How to configure the software and drivers for the older LCD driver boards.



WII NUNCHUCK projects with Arduino Leonardo AVR-T32U4


WII NUNCHUCK is low cost joystick and 3 axes accelerometer combo which could be read by I2C.

We created UEXT plug-in board which allow WII-NUNCHUCK to be used with any of our development boards with UEXT connector.

Here on this video:

you can see four projects made with WII-NUNCHUCK

1. Mouse – you can move the mouse pointer with Joystick and to use the two buttons as mouse buttons

2. Sound – with the 3 axes accelerometer you can change the pitch of the generated tone

3. Driving two servos with the 3-axes accelerometer

4. Drivinig RGB stripe with MOD-RGB and MOD-WII-NUNCHUCK – as AVR-T32U4 have just one UEXT port we use the UEXTx5 extender.

The demo code is at GitHub:

New Product: MOD-LED8x8RGB stackable RGB LED MATRIX


MOD-LED8x8RGB is intelligent 8×8 RGB LED module, it allow many modules to be stacked together.


If we look at the back side there are two connectors named EXT-IN and EXT-OUT when two modules are stack together EXT-IN of the one snap to EXT-OUT of the other so both get connected.

MOD-LED8x8RGB works with 5V power supply as you can see on the two sides there are big copper pads named VCC/GND and VCC1/GND1 when modules are snap together permanently (if you make big screen) is good these VCC-VCC1 and GND-GND1 to be connected between the modules so better power distribution is achieved.


to connect MOD-LED8x8RGB you will need ARDUINO working with 5V like OLIMEXINO-32U4 – make sure the power jumper is set to 5V as OLIMEXINO-32U4 can work both on 3.3 and 5V.

Then you should connect OLIMEXINO-32U4 to MOD-LED8x8RGB as on above picture in this way:

  • D13 -> EXT-IN.LATCH
  • 5V -> EXT-IN.VCC

All next MOD-LED8x8RGB modules snap together, if you make new row of modules use jumper wires to connect EXT-OUT of the most right module on the first row to the EXT-IN of the most left module in the next row and etc.

Working with Arduino led8x8rgb.h library:

led8x8rgb.h and font.h are necessary to work with MOD-LED8x8RGB, you can download them from GitHub:

how to use it?

first define how many matrixes you have connected by altering bigX and bigY numbers in led8x8rgb.h

then you can use color variable to set your color from 0 – black to 7- white

there are two other variables cX and cY which define where on screen to print text or characters and these get automatically updated after printing to new position

the library have functions available:

  • drawPixel(x,y) draws drawPixel at X,Y coordinates (1,1) is upper left corner
  • drawLine(x1,y1,x2,y2) draws line
  • drawRectangle(x1,y1,x2,y2) draws rectangle
  • drawSolidRectangle(x1,y1,x2,y2) draws solid rectangle
  • drawElipse(x,y,rx,ry) draws elipse
  • drawCircle(x,y,r) draws circle
  • drawTriangle(x1,y1,x2,y2,x3,y3) draws triangle
  • drawChar(c) – draws char at cX, cY and updates cX, cY
  • drawString(s) – draws string at cX, cY and updates cX, cY
  • lScroll() – scrolls all screen left 1 column
  • rScroll() – scrolls all screen right 1 column
  • scrollCharLeft(c) – scrolls one character from the bottom right matrix to the left
  • scrollCharRight(c) – scrolls one character from the upper left matrix to the right
  • scrollString( s, dir) – scrolls string left or right depend on dir

Restless_Dancer.ino, Sentence.ino and Winking_Face.ino are demo codes made with led8x8rgb.h library.

Note that MOD-LED8x8RGB is not simple shift register matrix, but have microcontroller inside, so once you shift the info IN and LATCH it the microcontroller takes care to refresh the image on the matrix, this way with slow SPI you can drive large displays as no need to permanently shift new and new images to the screen as on the dummy RGB matrixes.

Here is video of the demo code from the GitHUb:

MOD-RGB – Arduino, Maple and Pinguino Examples


Here we will demoнstrate you how to use our new MOD-RGB LED driver UEXT module with our Arduino, Pinguino and Maple boards which have UEXT connector.

Getting the Libraries and Examples

The library/example .zip files for Arduino, Maple and Pinguino can be downloaded from:

Installing the Libraries and examples

For Arduino, use the Fade sketch directly, no additional files or configuration needed.

For Maple:
1. Make sure that the Maple IDE is not running
2. Copy the MODRGB folder to the /libraries folder of your Maple IDE installation folder
3. Start the IDE. The “MODRGB” examples should now appear under File/examples.
4. Include the library in your projects as such:
#include “MODRGB.h”

For Pinguino, use the example directly. It has been tested with PIC32-PINGUINO, PIC32-PINGUINO-OTG, PIC32-PINGUINO-MICRO, PIC32-PINGUINO-MX220


All packages include the same example – Fade.

It uses built-in functons or the MODRGB library to set the RED, GREEN and BLUE values that the MOD-RGB board outputs.

The example fades the lights from blue to red to green to blue again in an endless loop.
If you want to adjust the speed at which the colors change, change the value of the delay period to your liking:
#define SPEED 500


A13-OLinuXino serving MOD-RGB and WEB-CAM for live stream


In the previous post I wrote how A13-OLinuXino runs Apache server and you can control MOD-RGB strip over the internet, now the A13-OLinuXino service is available online at : you can open this URL and see actually web pages served by A13-OLinuXino

What’s new Dimitar Gmishev did is to connect USB web camera to A13-OLinuXino too, so now you can see the RGB stripe response to the web cntrol.

To see the MOD-RGB stripe via the web cam you need video player – in our case this is open source Kantaris player with Ctrl-B you force it to play stream from internet URL and point it to : and you will see the web cam video stream, so when you change the RGB color control you see the result on the camera!

Have fun and try it yourself

A13-OLinuXino web server with MOD-RGB controlling RGB LED stripe over internet


A13-OLinuXino have enough power to run real apache web server with php5, java script etc like any desktop linux computer.

With MOD-RGB connected to A13-OLinuXino UEXT you can control RGB LED stripe up to 5A per channel over fancy web interface from any device with web browser like your tablet or phone.

For instance you can make cool RGB LED lighting in your home and to control then with your phone, A13-OLinuXino can connect to many different MOD-RGB controllers as they are addressable, so you can connect many LED stripes to A13-OLinuXino web server and to controll them separately.

These are step by step instructions how to duplicate yourself:

Prepare A13-OLinuXino-WIFI for web serving:

Update repository
$apt-get update

Install apache and php
$apt-get install apache2 php5 libapache2-mod-php5

Open browser and type A13 board internal network IP address. For instance . You should get message “It Works”

Extract demo files into apache dir. For example /var/www/RGB

Compile i2c-tool
$gcc i2c-tool

Make executable
$chmod 777 a.out

Change permitions of i2c-bus
$chmod 777 /dev/i2c*

Now open index.html. You should see color picker. Move mouse. Enjoy 🙂



MOD-RGB is our new 3 channel RGB LED controller. Each channel can control 12V 5A LEDs so it’s suitable to control high power LEDs and RGB LED stripes.

MOD-RGB directly connects to UEXT on A13-OLinuXino, iMX233-OLinuXino, OLIMEXINO-328 Ardino like, DUINOMITE(-MINI-MEGA-eMEGA), PINGUINO, OLIMEXINO-STM32(MAPLE) and we have demo codes for all these boards. With the help of RPI-UEXT it can be connected to Raspberry Pi also or Stellaris launchpad via STELLARIS-UEXT.

On top of I2C RGB control you can use MOD-RGB as Disco Light controller when you feed Audio singal to the audio connector the R, G and B channel will blink with the low-mid-high frequencies beat.

There is provision MOD-RGB to become DMX controller with MOD-RS485 connected to the UEXT connector, but the firmware is not complete to support DMX yet.

Today at 17.00 o’clock our local Bulgarian time (GMT+2) we will post on Twitter our questions.

You have one hour to reply to our tweet with the correct answer.

At 18.00 o’clock we will count the correct answers and ask to generate random number in range then announce the winner and ship the board by airmail in Monday.

Good Luck!