Hauke’s Projects

Simple Capacitive Water Sensor for a Water Container

From simple, standard electric cable I built a capacitive sensor to assess the water level in my water container. While the circuit was replicated from this blog (thanks for sharing!), I’d like to share how I built the actual capacitor.

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Lessons Learned: Measure Water Levels in a Barrel with SR04-Type Sensors

Using ultrasonic distance sensors I monitor water levels for my garden irrigation system. I have an underground rainwater cistern and a wooden barrel as an interim water storage in the sun to have the water warmed up before use. I started off with the classic HC-SR04 ultrasonic distance sensor, but it turned out to be a bad idea for the warm water barrel: Moisture and temperatures up to 40°C in the summer sun made the sensor rot within half a year down to complete failure. I switched to AJ-SR04M watertight sensor (which seems to be very similar to JSN-SR04T which is often also mentioned on the internet). This has a higher minimum distance (~20 cm vs. ~2 cm), and a much larger opening angle (45° to 75° vs. 15°) as compared to the HC-SR04, and in this post I describe how I dealt with that.

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Quick Thing: TARDIS Housing for Raspberry Pi modded for Raspberry Pi 4

This is just a quick note that I updated my Tardis housing for my media center to now hold a Raspberry Pi 4. The new version features:

  • An improved “POLICE public call BOX” sign
  • A hole for a 5 mm LED in the top for a shining light
  • The necessary holes for USB-C, 2x Micro-HDMI and Audio out
  • A removable top

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Replacing Fabtotum Hybrid Head v1 Hotend with E3D Lite6

I replaced the stock hotend of the Fabtotum Personal Fabricator Hybrid Head v1 by an E3D Lite6 hotend (The full metal V6 should work the same way). In this post I describe the steps to remove the old hotend, get in the new hotend and the simple modifications to the firmware that were required.

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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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Root shell on a MStar based UMC TV (Sharp LC-24CFG6132EM)

Not being happy with a few things on my Sharp LC-24CFG6132EM smart TV, I decided to dig deeper, hoping to find ways to reconfigure some settings. While I not achieved that goal yet, I at least managed to gain root access to the Linux running on the TV. Since the TV set is based on a MStar product, I suspect that my procedure will work for any MStar based TV, at least those manufactured by UMC, which for Europe own the brands of Sharp and Blaupunkt. So here I document the procedure.

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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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Building a Media Center for German IPTV

The Raspberry Pi with Kodi is a versatile media center. Getting it to work with German IPTV in a stable fashion is however somewhat challenging. In this post I outline the necessary steps to set up a XBian based media center, to make it usable on a rather small SD TV screen, to avoid the 30 minutes offset problem with the public German TV stations, to make the channel mappings stable and to control the media center via IR remote control.

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