In my earlier post I showed how I have installed the open source openHAB home automation system (see “Installing openHAB Home Automation on Raspberry Pi“). In this post I show how to control a local LED on the Raspberry Pi with openHAB home automation system: how to control any GPIO pin on the Raspberry Pi from remote:
Controlling the LED with openHAB
I’m currently building a home automation project around Raspberry Pi: I want to be able to monitor and control things like the lights, garage doors and the heating system both at home and from remote. I already have added a touch screen to one of my Raspberry Pi 2 computers (see “Adding a Touch LCD to the Raspberry Pi 2“). This article is about how to install the openHAB on that Raspberry so it can be the brain of the automation system.
openHAB Demo House on Pi
Question: What is the IP address of my Raspberry Pi?
I use my Raspberry Pi’s usually with an external VGA or HDMI monitor. How cool would it be to use a touch LCD screen instead?
Raspberry Pi 2 with 7 Inch Touchscreen
For years a coworker is using a BBQ smoker to prepare a turkey for Silvester dinner. After hearing him so many times about how excellent this is, time to try this out myself. I cannot wait for the year-end, so I have put a full size turkey into my smoker today 🙂
Turkey after one hour
For a space project we have to make sure that things are not failing while our hardware orbits around the Mother Earth. Therefore we are using different static and dynamic analysis tools, and one of it is using PC-lint from Gimpel to catch as many errors and bugs as possible. For that project, we are using Eclipse with the GNU ARM Embedded (launchpad) ARM compiler and Eclipse as IDE with the GNU ARM Eclipse plugins. There are commercial plugins available for linting with Eclipse (e.g. Linticator), but with a few tweaks it is possible to lint with Eclipse free-of-charge. So this article is about how to lint an Eclipse (Freescale/NXP Kinetis Design Studio) project with PC-Lint.
Lint messages in Eclipse
When I left for the week-end, I missed to take with me my Segger J-Link debug box. I have one P&E Universal Multilink at home, but I needed a Segger J-Link to use the SystemViewer with my robot. I need that for a FreeRTOS trainig I will deliver in Poing/Germany on Monday at Avnet/Silica.
But I had a Freescale KwikStk board at home, and I did remember that I can use that board as a Segger J-Link to debug my custom hardware (see “Freescale Kinetis KwikStik (part 1)“).
Debugging Custom Board with KwikStik
In case there are problems with the C/C++ preprocessor, it is useful to generate the compiler preprocessor listing. Here is how to create a preprocessor listing with GNU gcc compiler and the GNU ARM Eclipse plugins in Eclipse:
Preprocessor Listing in Eclipse
Readers of my blog know: I’m not a fan of printf(), and I think for many good reasons. Still printf() is widely used, and the GNU gcc tries to optimize things. This is observed with a simple example: If I’m writing
printf("a");
Then the code produced (ARM Cortex-M0+ with GNU ARM Embedded 4.9 2015q2 gives:
movs r0, #97Â Â Â ; 0x61 bl 0xa98
Instead of calling printf(), it is calling putchar()! Why is that?
PutChar instead of Printf
One of the most important aspects for developing complex realtime applications is get insights into what is going on the target. Segger just has released a free tool which gives an incredible useful insight view and visualization:
Segger System View for FreeRTOS
MCU on Eclipse 