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Reboot the Raspberry Pi on network failures (brcmfmac: brcmf_cfg80211_scan: scan error -110)

In one of my earlier blog posts I reported that occasionally the HABpanel will disconnect from the server. Turns out it's not HABpanel, but it's the Pi itself which is causing the trouble. Part of the problem why it took me so long to investigate is that the display is in the kitchen, and someone had to have a look and spot the small red error message. To work around that problem, I hooked the device up in the network monitoring, and had an alarm triggered when the device is not reachable. Sure enough, that happens occasionally.

Because I moved /var/log to a small RAM disk to avoid wearing out the SDcard, all logs are lost once the device is rebooted. Had to bring keyboard and mouse to the kitchen in order to save the logfiles once the device was no longer reachable over the network.

 

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Dim the Raspberry Pi screen

The new Raspberry display works nice, but the screen is too bright. At night in the kitchen it enlightens the entire room - unnecessarily. Since I'm using the original Raspberry Pi 7" touch display, the brightness can be controlled in /sys/class/backlight/rpi_backlight/brightness. This "file" can hold a value from 0 (display off) to 255 (full bright).

 

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Occasional HABpanel disconnect from the openHAB server

The new display showing HABpanel works quite nice. But occasionally the fullscreen browser will lose the network connection. As far as I can see, it's not a Wi-Fi problem of the Raspberry Pi, but still annoying: in the morning the browser shows a small red warning that the connection to the openHAB server is lost, time is still correct, but temperature and the status of other devices is outdated. To fix that, I have to leave fullscreen mode, hit reload - and then there is no keyboard for going into fullscreen mode again (that's using the F11 key).

 

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Automatically start a fullscreen browser on a Raspberry Pi - show openHAB HABpanel

The Raspberry Pi with the touch display for the home automation system is coming along nicely. One problem to solve: how to display the openHAB HABpanel, and which browser to use?

Firefox and Chrome don't run on Raspbian. However "Chromium" (the open source part of the Chrome browser) is. That's a good start. But how to start the browser automatically, and in full screen?

 

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Raspberry Pi: disable Wi-Fi powersave, and stay connected all the time

Recently I installed a Raspberry Pi with Raspbian, and attached a touchscreen to it. The device is supposed to work as a display for our openHAB home automation system. All nice and shiny, except the Pi occasionally disconnects from the Wi-Fi - apparently in order to safe power. Once the network device is needed, the Wi-Fi is reconnected. That is the default setting.

That is quite annoying, because the HABpanel will lose it's connection to the openHAB server, and no longer show widget updates. Some widgets like "time" will just continue to work, but other widgets like status of the washing machine, or the current outside temperature just show the last state, and never update.

 

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Avoid "wear out" of SSD-cards in an openHAB system

You might know that problem: the brand new SSD in your system is super fast, but after a good time using it, the card is dead. Unlike spinning disks, which usually fail over time, and show I/O errors by blocks, SSD cards are prone to a problem called "Wear leveling". Blocks which are written more often will "wear out", and become unresponsible. More writes increase this risk. And a typical openHAB system does a number of writes all the time: every time an external status changes, it's written to the event log. By default the syslog is written to disk as well, and then there is a myriad of systemd services, writing status information into files.

 

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Install openHAB2 bindings using Ansible

Recently I started looking into Home Automation, using a Raspberry Pi and the openHAB as platform. The website provides ready-to-go images based on Debian, named openHABian. Me being me, I decided to install the image, let it boot up for the first time, and then take it from there using Ansible as automation tool. That's a bit more effort in the beginning, but ensures that I can always just wipe the SDcard, and start over from the beginning. Especially useful if I screw up at some point during testing.

One of the first steps to do is to decide which bindings, or extensions, are needed. Bindings provide openHAB with information about what kind of hardware and input sources are available out there. The list of available bindings is long, and one can use the UI to click and install bindings, before starting to configure and link them. That process is not idempotent, but luckily openHAB also provides an API which can be used to execute the same steps, just faster and automated.

 

 

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