Extending the Battery Life of Your IKEA Motion Sensor: Replacing CR2023 Cells with AA Batteries

Posted on 15 January 2025 by admin

The IKEA TRADFRI motion sensor is a versatile and affordable device that integrates seamlessly into your smart home zigbee setup. I personaly use them in a cuple of places, in the postbox to notify me on new mail and in some rooms to switch on the light. However, its reliance on tow CR2023 coin cells can be a bit of a drawback. These small batteries, while compact, tend to have a relatively short lifespan, especially in devices that see frequent use. Further more in my use cases a small form factor is not needed, so I decied I’m tired of frequently replacing the coin cells. My solution is replacing the CR2023 cell with AA batteries.

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Unlocking Time: Harnessing the power of temporal tables in SQLite

Posted on 19 February 2024 by admin

SQLite is a remarkable, versatile and widely adopted embedded relational database. SQLite’s lightweight nature, ease of integration and broad cross-platform support make it a go-to choice for developers seeking an efficient solution for storing data. Also, SQLite is very capable, but some features aren’t included out of the box. One of those not-included features is temporal tables. What that feature is, why it’s useful, and how to get it working with SQLite will be described in this post.

What are temporal tables?

Temporal tables, also known as temporal data tables, are a feature in database systems that allow you to keep track of states of data over time. These tables store historical versions of data, providing a way to query and analyze how data has evolved over different points in time. A mechanism to fly back in time, so to speak. Such a feature is especially useful when handling data that does not only consist of immutable facts, but also data that is mutable or somewhat mutable. There is more mutable data than one might think. Let’s look at an example, a table of employees:

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Modern TLS Version for dovecot & postfix

Posted on 4 March 2023 by admin

(TLS 1.2 or newer)

You can use the following settings to ensure that Dovecot and Postfix use a modern TLS version:

For Dovecot:

  1. Open the file /etc/dovecot/conf.d/10-ssl.conf (Debian).
  2. Uncomment the line starting with ssl_min_protocol and set it to ssl_min_protocol = TLSv1.2.

For Postfix:

  1. Open the file /etc/postfix/main.cf (Debian).
  2. Add the following directive: smtpd_tls_mandatory_protocols = !SSLv2,!SSLv3,!TLSv1,!TLSv1.1.

Finally, reload Postfix with systemctl reload postfix and restart Dovecot with systemctl restart dovecot.


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Setting up timesync via NTP on debian & raspberry pi

Posted on 6 January 2023 by admin

I use systemd-timesyncd to keep the system time up to date on my raspi / debian system.
To do so i did the following steps:

1. Check the state of timedatectl
Therefore type the comand timedatectl to the shell.
The output should look something like this:

Local time: Fr 2023-01-06 19:34:27 CET
Universal time: Fr 2023-01-06 18:34:27 UTC
RTC time: n/a
Time zone: Europe/Berlin (CET, +0100)
System clock synchronized: no
NTP service: n/a
RTC in local TZ: no

The important part is “System clock synchronized: no” and “NTP service: n/a“. This tells us that there currently is no timesyncing via systemds timedatectl.

2. Install systemd-timesyncd

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Erase ESP – quickly reset the wifi chip

Posted on 31 December 2022 by admin

TLDR:
Install esptool.py
pip3 install esptool

Erase flash of the esp
esptool.py -- erase_flash

One of my smart ESP devices wasn’t responding after a power down.
I debugged the problem by connecting it to a serial interface. On the comandline I saw that the chip wasn’t able to connect to its WIFI. To check wether the chip was fried or if its just the software thats messing around I had to delete all of its storage, to reflash the software afterwards. To do that i used the comands stated above.

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