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Monday, October 19, 2020

Configuring Home Assistant to run off of a USB drive in a incompatible Raspberry Pi

 A problem with the earlier generations of Raspberry Pi's, especially the Pi 1 and the Pi 2 up to version 1.1, is that these cannot be configured to boot from an external USB storage device.

This is a particular relevant limitation for a number of reasons, including the fact that relying on an SD card for most of the storage needs is a solution that may have limited endurance.

The later versions of the Raspberry Pi (RPi 2 v1.2 and upwards), already offer some form of allowing external USB media to boot the operating system. 

Sunday, October 18, 2020

Improving an RPI 2 based Home Assistant server for reliability and performance

For some time I have been using the same Raspberry Pi 2 v1.1 as the infrastructure for my Hass.io instance. It proved to perform quite reliably over the approximately 18 months I have been using it 24x7. From that time during approximately 1 year I used the same SanDisk Ultra XC I 64 GB MicroSD card:


Just for precaution I have later switched to a similar card, a SanDisk Ultra HC I 32 GB, and moved my Hass.io installation onto it:


Saturday, June 20, 2020

Building a hardware watchdog timer for a kiosk or other system that needs to run 24x7 - version 2.0


My previous post covered a first version of a watchdog timer that I used in the past for another project. 

You may check it here.

As I mentioned there, I suspected that a somewhat different design would be necessary, because the target device could not have either GPIO pins available for allowing a keep-alive signal to be sent to the watchdog timer, or even if it had, it would be unlikely that the underlying linux OS on the Android system could not have the necessary drivers or support for changing the output of such pins.

Saturday, May 2, 2020

Building a hardware watchdog timer for a kiosk or other system that needs to run 24x7


It was proven by Alan Turing back in 1936 that the halting problem applies for computing in general, and our contemporary computing machines are no exception.

Would predicting the crashing of an algorithm or program be a possible function, and we would be able to know the edge cases that cause an application to fail or enter a loop, without having to explore the actual scenarios to find these edge cases. To put it simply we would only have to ask the algorithm in which conditions it would enter a loop or end unexpectedly, and by not providing these inputs we would with absolute certainty not enter these scenarios.

Monday, April 27, 2020

Building a kiosk for Home Assistant from scrap parts - Part 2


With a project of this type, the hardware preparation is just the tip of the iceberg. It was thoroughly explained in the last post, despite one last change still being pending. What lacks is basically the addition of a resistive touch panel to the front of the screen, in order not to depend on the mouse as a pointer/input device. The panel is still somewhere between China and my location..

The first aspect that I found important to cover, now that I had this Android based kiosk up and running, was the ability to remote control it and launch arbitrary applications and services on startup.

Saturday, April 4, 2020

Building a kiosk for Home Assistant from scrap parts


It is great to have automation in the house providing increments of comfort such as eliminating manual tasks like cleaning the floor, or to aid in managing the energy consumption by turning off lights and appliances which are not in use, or in the safety side, by providing intrusion detection or monitoring the presence of gas leaks or other hazards, and executing the adequate actions.

Sunday, March 22, 2020

Tasmota-based multi-channel air quality sensor station


The sense of smell is an amazing function in vertebrate animals. Even the human nose, which is not particularly notable in comparison with other animals, is fascinating in its sensitivity to trace amounts of a large variety of substances. It has a level of selectivity and capability of distinguishing between different kinds of smells, which is very difficult to match by even the most sophisticated artificial sensors.

Having as the main motivation the enrichment of the IoT gadgetry sitting around in my house (and eventually fill up an entire 192.168.1.1/24 network address range), I found that (after the motion and entrance detection device), an interesting device to invest time on would be something capable of sensing multiple air quality parameters at the same time.