CEC-like Power Features with Non-CEC-Equipment
With a Raspberry Pico, I monitor my Sony amplifier from the 90s and my 2013 Dell monitor, and switch on my NUC-based media center if any of these devices are switched on. This is comparable to the CEC functionality that more modern devices provide via the HDMI port. I also utilize the USB/serial interface of the Pico to check if any of the two devices is still on to include this into my auto-shutdown script logic.
As a result, my media center boots up as soon as I switch on my amplifier or my monitor, and only auto-shuts down if both are off.
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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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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.
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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