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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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: 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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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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Case for MP1584 Based Step-Down Converter Board with USB Port
This post is to share my self-made 3D printed housing for a 5V USB voltage converter. Since the used converter board is quite common, I guess others may profit from this design.
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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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