wtorek, 2 stycznia 2018

Connect to the bluetooth serial port in linux

From time to time I use my bluetoth module HC-05 to communicate with microcontroller. Every time I have the same problem because I don't remember how to do that. Short receipe working for me (at least for openSUSE):
 sudo bluetoothctl  
 power on  
 agent on  
 scan on  
 pair <MAC>  
Then:
 sudo killall rfcomm  
 sudo rfcomm connect /dev/rfcomm0 <MAC> 1  

/dev/rfcomm0 is ready to use now.

source

piątek, 22 grudnia 2017

Nixie clock #2 - multiplexing

Previous post: Nixie clock #1

I had to choose my project for embedded systems classes (containing some kind of display, communication module, some other parts like sensors, etc.) and I proposed to continue with my nixie clock. I will have to add automatic time downloading from the internet. I'm going to use cheap & popular wifi module esp8366:


Today I finished my second PCB for this project, board performing signal multiplexing for tubes. Inputs are HV from the boost converter, digit and tube activation signals. On the output correct tube gets power supply and specified number pin is driven. I put a lot of work into it (done in period of 2-3 weeks in the evenings), fortunately the board works:



Nice views by copper & salts during etching so waiting wasn't too boring :)

środa, 6 grudnia 2017

Serverless architecture

Recently I've heard about idea called "serverless architecture". This is the next architecture proposal for web applications after very popular in recent years microservices. To be short, in this approach developers don't have to care much about server-side infrastructure. Great description can be found at martinfowler.com. Serverless concepts can be found in big providers' platforms like AWS or Azure. As I see on Azure platform there is 1M free function invocations per month what allows to create & start small applications for free. Development can be rapid due to provided integrations (in Azure - Logic Apps) with popular services (Salesforce, Office 365, Twitter, Dropbox, Google services).

wtorek, 13 czerwca 2017

Watermark for LibreOffice Writer

Recently I was working on Watermark feature for LibreOffice Writer. In case of TSCP Classification it was possible to add "Confidential" watermark in the document background. I extended that with possibility to add custom text, font family, color, transparency level and angle. Additional dialog was introduced in the menubar under "Insert" > "Watermark...".


I improved also export and import for that kind of shapes from .dotx files. Now font-family is correctly loaded:


RTF import also was improved, before Watermark was visible as a plain text:

czwartek, 4 maja 2017

AutoText import from .dotx and .dotm files

In the LibreOffice Writer user can prepare some pieces of documents which can be reused later. That feature is called AutoText and is accessible using menubar (Tools - AutoText). In the AutoText dialog it is possible to manage existing entries and also import new ones from files.
So far only *.dot and *.doc file formats were supported for importing AutoText. Here was my first task at Collabora: to add .dotx and .dotm format support.

One template document can contain multiple AutoText entires. Each entry has own name and can consist of formatted text, text with graphics, tables or fields. To import new templates user need to open AutoText dialog (Tools - AutoText), select according category and from the "AutoText" menubutton choose "Import". File explorer will appear. In the file format listbox new entries were introduced: "Microsoft Word 2007-2013 XML" and "Microsoft Word 2007-2013 XML Template" for *.docx and *.dotx or *.dotm.

AutoText has own long name and shortcut. It is possible to insert AutoText after typing shortcut name into document and pressing F3.

Following GIF shows *.dotx import with complex content (table, shape, formatted text and fields):

niedziela, 16 kwietnia 2017

Linux rescue after Windows 10 Creators Update

Last night I've updated my Windows 10. That was big update called "Creators Update". I don't know details what was changed (I noticed only new privacy settings and mail client) but one thing was significant for me as a linux user. When I wanted to switch to my openSUSE it opened rescue mode. It happend after I entered password to my encrypted home partition. My first thought: update modified my partition! Fortunately it was possible to open and mount it using cryptsetup. I checked also /etc/crypttable and I realized what is the root cause of my problems.
In my config I found /dev/sda7 but my current encrypted partition number is 6! Fast research and I found empty space on my disk between two partitions. Possibly the update removed one of partitions existing before (created during Windows 10 installation) and now all my linux partitions have decreased numbers.
I created new partition in the empty space. Reboot. Linux works.