Topic: Computer

Hardware, software & hacks

WiFi plug with Tasmota – Delock 11827

Caution: the following instructions are only suitable für the Delock 11827 and can not be used for the Delock 11826 without energy measurement! You must not use the hardware template for the Delock 11826!

With the Fritz!Box 7390 I have already used a number of switching plugs from AVM, specifically the Fritz!DECT 200 and later also the Fritz!DECT 210. In addition to the switching function, these devices also offer measuring power consumption and temperature and can also be switched by sound if desired, e.g. when you clap your hands. However, this also has its price: currently you can get these devices, if at all, for no less than 60-70 EUR. In the past, you had to budget at least EUR 50 for it.

Delock 11827 WiFi plugBut since I’ve been using Home Assistant, there are also alternatives.

The Delock 11827 is a device with energy measurement in which Tasmota is already pre-installed. An ESP8266 with 1 MB memory is used as the controller.

With a sales price of around EUR 20, the device is also significantly cheaper than the solution from AVM. However, there is no temperature measurement or noise detection. On the other hand Tasmota offers a very extensive programming option with timers and you can also correct the measured values via console commands if necessary and change the switching function of the relay to permanently “on” if you want to use the devices for energy measurement only. An HTTP API to control the device is also available.

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Nextcloud Office

In the meantime I have been using Nextcloud on my own servers for several years and also an Office integration in order to be able to edit documents together with others directly in the browser. Originally, I chose OnlyOffice because it was much more mature than Collabora in 2018.

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Home Assistant

Tasmota, web interfaceRecently I’ve been working on a small craft project: extending an IKEA Vindriktning air quality sensor with a D1 Mini to read the data and forward it to a server via MQTT.

See also Sören Beye’s Github repository for the conversion. However, instead of this firmware, I use Tasmota based on these instructions from Blakadder, which is much more convenient to set up and configure. See also the Tasmotizer on Github.

When I was looking for a suitable server, I quickly ended up at Home Assistant. This is a free software solution for integrating numerous smart home devices and can also be used on a Raspberry Pi 3 or 4. In my case this is a Raspberry Pi 4.

Update 2022-08-14: In the meantime I have expanded this with another sensor for CO2, relative humidity and temperature, see the article here.

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Does anyone remember Meltdown and  Spectre? These vulnerabilities were discovered in June and July 2017 and publicly documented in early 2018. As a result, countermeasures have been taken by software manufacturers for both operating systems and applications, some of which also lead to reduced performance.

As reported on, researchers of the ETH Zürich now discovered a vulnerability in one of the counter measures – retpoline – affecting CPUs by Intel and AMD which got the name “Retbleed” (CVE-2022-29900, CVE-2022-29901). Also see the description at