Hauke’s Projects

Playin' around with Electronics and Computers

Project

Anything that as result has a tangible, (hopefully) useful thing.

Media Center Auto Shutdown and RTC Wakeup Based on tvheadend Recording Schedule

I created a script that runs via cron job that will power off my media center if it is not in use, but will program the real time clock (RTC) on the motherboard to wake up the system in time to run a scheduled recording, and/or to update the EPG data, and from that derive potential new or changed auto-recordings. To determine if the system is currently not in use, I

  • Check if the monitor is off
  • Check if any audio is playing, e.g.,  Spotify or KODI is playing anything
  • Check if the wireless keyboard is connected
  • Check if tvheadend is currently recording something

Also, the shutdown processing can be blocked by creating a flag file. If that file exists, no shutdown will happen.

The wake-up time is either the next recording time plus some allowance for boot time, or every 24 hours, whatever comes first. This makes sure that at least once a day the EPG is updated and tvheadend can update its auto-recording-schedule.

As a result, I reduce power consumption of the media center considerably.

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Soil Water Sensors: Problems with the Ubiquitous DFRobot Capacitative Sensors

Capacitative soil moisture sensors based on this DFRobot-design (and its successors) can be found in numerous blog articles about irrigation automation. For me, they do not work out for two reasons: a) A notable temperature dependency of the measurements, and b) a high failure rate after a few months to a few years. I decided to adopt the concept of my Simple Capacitive Water Sensor for a Water Container for soil moisture measurement, which turns out to work well.

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Modified Housing for Alber e-motion M25 Remote Control

For a relative that’s paraplegic, I modified the housing of the remote control for the electric wheelchair wheels Alber e-motion M25 to make the usage easier. Mainly, the small housing was made thicker and larger for better handling. Also, one knob was moved to a different position.

The project is not very sophisticated, but I publish it anyhow – perhaps some other handicapped person can benefit from it.

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Convert Window/Door Sensor to Handle Sensor

In order to prevent my venetian window blinds to go down on timer in front of my open window-style terrace door, potentially locking me out, I needed to know if the door handle was in the “open” position. However, I did not want to use a battery powered radio sensor, but the existing door open/close magnetic sensor in the door frame. Here’s my solution.

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Legal EPG Scraper for ARD TV Stations to Use With tvheadend External XMLTV Grabber

I wrote a Python EPG scraper for the EPG data of the German TV stations broadcast by ARD. It is legal for private use. Here I share the code and my thoughts behind it.

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Interfacing EasyMeter Q3M via Info-Interface

The installation of my fuel cell heating required a bi-directional power meter. Bonn Netz, my local power network provider, uses meters of type EasyMeter Q3M which have two infrared interfaces: A bidirectional D0 interface, and a read-only info interface. I use the info interface (INFO-DSS) to read out power consumption and production of the three phases. For this, I built an optical interface, a 3D printed housing for it, and use the UART of a Raspberry Pi with python to get the values.

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RFID Treasure Chest for LARP

I built a treasure chest which opens if a riddle is solved. To prove that the riddle is solved, the players need to put the correct three RFID/NFC tokens (out of several tokens to choose from) onto three RFID readers in the correct order. If they fail too often, a curse is uttered! In this post I describe the hardware selection, the electronics, the assembly and the software.

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Interfacing Vitovalor 300-P with a Raspberry Pi

I want to integrate my new Viessmann Vitovalor 300-P fuel cell heating into my home automation. For this, I use the Optolink interface, vcontrold from the openv community, and create my own configuration files from several sources.

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Motion Sensor PoC: BNO055 and Raspberry Pi Subtleties

The BNO055 is a capable IMU that has on-chip sensor fusion and filtering. Interfacing can be done using I²C and UART. When used with the Raspberry via I²C, you get erroneous measurements because of the I²C clock stretching bug of the Raspberry. Using the UART, results are correct.

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Title Image Project: LED Controller

To create a lamp with adjustable color temperature and brightness, I use a warm/cold white dual LED strip, an ATtiny45 MCU with N-channel MOSFETs and two adjustable resistors. This article contains the hardware and software setup. The title image of this blog shows the project.

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