wtorek, 27 marca 2018

Highlight colors customization for Calc

In Calc it is possible to activate "Value Highlighting" mode (Ctrl + F8). When activated, Calc displays cell contents in different colors, depending on type. By default Text cells are formatted in black, formulas in green, number cells in blue, and protected cells are shown with light grey background, no matter how their display is formatted. There was no possibility to change default colors what could be a problem for a color blind person. During my work for Collabora Productivity I introduced new entries to the "Application colors" tab in Calc options to fix this issue:

czwartek, 15 lutego 2018

Nixie clock #3 - NodeMCU & auto time update

Previous post: Nixie clock #2

Recently I finished my clock (electronics). All the code is uploaded on my github profile: clock repo.
I added automatic time update done by NodeMCU which connects to my predefined WiFi Access Point and after receiving the time, sends it over UART to the atmega microcontroller.

Spaghetti for testing and results:

Now I should design a case for this device...

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).