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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European WordPress Bloggers beware: “Abmahnwelle” due to Google Fonts!
WordPress admins are currently sued for using Google Fonts directly from the Google servers without correctly informing users about the data collection by Google. I give a few hints on how to protect yourself against this. Disclaimer: I’m not a Pro in legal regards, so take everything I say with a grain of salt.
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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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Quick Thing: Case for Diamex All-AVR Programmer
The Diamex/Tremex All-AVR programmer for ATmel microcontrollers comes as “naked” populated PCB, no case, no protection against shorts or other damage. I created a case for it, with the following design criteria:
- Protection against accidental shorts as good as possible.
- Easy access to the jumpers that control the various operation modes.
- “Park position” for the jumper that de/activates the external power (since it is often in “off” position and can easily be lost).
- LED signals need to be visible.
- Uses the existing mounting holes.
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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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Quick Note: Modify the WordPress Comments Cookie Consent in an Update-stable Way
It always bothered me that I could not modify the text (“Save my name, email, and website in this browser for the next time I comment.”) of the cookie consent checkbox in the WordPress comments section to explicitly mention that it uses cookies. Continue reading “Quick Note: Modify the WordPress Comments Cookie Consent in an Update-stable Way”
Floating Table of Contents
I wanted to have a floating table of contents for my posts, but could not find any free plugin that allowed me to do so. Using a combination of plugins, I created a floating TOC myself, which is not perfect, but good enough.
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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