Thomas shares makes

Rainwatertank Usage meter

Home assistant graph of water usage, the lightest shade is rain water measured by DIY solution, the darkest shade reported by the tap water utility meter over P1 connection.

I integrated a 7€ YF-B7 water flow sensor into my home assistant setup using an off the shelve 35€ modbus based pulse counter.

Laser engraved and etched circuit boards!

etch tank

Nowadays diode laser engravers are powerful enough to cut through a few millimeters of wood and you can get a fairly large one for under 200 euros.

Cutting wood into shapes always was a makerspace thing I loved to have in my home lab, but it didn't justify buying one.

A laser engraver can also make it easy to prepare bare circuit boards for etching at home though! I'll explain how I do this, and how it makes creating PCB's very easy if you have an etch tank in your lab.

DIY Heatpump drip tray

My drip tray, installed.

An outdoor heatpump unit pulls water from the air since moisture condenses on its cold radiator. In very cold temperatures it forms ice, which is suddenly thawed all at once in a 'defrost cycle'. Our outdoor unit was installed over our driveway, and we walk under it on the way to our back door.

The installer did not place a capture tray, but I want to avoid water dripping and pooling on the driveway during the heating season so we don't get a slippery ice spot or perhaps the continuous flow of water might even find its way into the brick wall.

Custom motion sensor wall mount

A motion sensor with pushbutton behind it.

Motion sensors; the simplest kind of automation, and the most useful. Especially during night, when you're finding your way to the smallest room in the house. I could not find a sensor I liked however, and also did not want to spend a lot of money on something ugly.

A friend of mine built just this, with the exception of using glue to stick it together. I designed and 3D printed a slightly more complicated contraption, which can be pushed to bring the room light up from night setting to full brightness.

Rollershutters

Shutter control panel

When we renovated our living room, we upgraded the window roller shutters with electric motors. While we usually only open and close all of them together, we still want to be able to set them to individual positions. I decided to make a central control panel with 6 physical buttons and implement some logic in the Siemens Logo controller to control the motors.

Virtual Solar/Grid power meters

I want to keep counters for how much solar panel energy and grid energy my car uses. I have power meters for the Solar, Grid and the car. The power the rest of the house uses is however unknown, and measured by the grid meter. Determining the car's part of grid and solar power requires some calculations.

I created home assistant template sensors to come up with these power numbers, and added integrators to obtain energy meters. The energy flow plus card can show these in real time on the Home assistant dashboard.

Solar Matched Electric Heating

A heater power-controlled to consume all excess solar production!

I built a prototype test setup that makes sure every Watt produced by our solar panels is used by an electric heater. It uses an industrial power controller and some code to match the heater's power usage to whatever power is not used by the house.

This would make it possible to maximize our solar self consumption, which is required to get a decent return on your solar investment.

For us, injecting to the electricity grid is giving away power, we have to pay about 15x as much compared to what the utility pays us for returning energy to the grid.

Rainwater Pump and filter box

I chose to place our our rainwater tank's pump and filter in the garden shed slightly away from the main house. This allowed for a cheaper pump outside the tank and minimizes in-house technical equipment and noise.

First steps with Rust on the stm32

A stm32 based traffic light I built for fun (and my kids) years ago

Since the Rust programming language is all the rage, I started exploring this programming language during the summer. These are my notes on what I needed to do to set up a working development environment using the hardware I already had in my lab.

OpenPlank Proof Of Concept

The first (crude) prototype with sloppy veneer edges

In November I saw a cool device at an event. The device was presented as an unobtrusive way to interact with technology. Unlike usual touch screen devices, it looks like a wooden plank that is sensitive to touch and uses a LED pixel matrix behind the wood to visualize icons and text.

Since the device wasn't available for sale, I wondered how easy it would be to DIY a (much) simpler version that I could use for some of the same tasks.

I worked on this for a few hours each week, and by the end of December I had this simple proof of concept, making use of cheap parts and easy to assemble.

I call it the OpenPlank. Check it out...

Rainwater Tank Plumbing

After having the rainwater tank installed and connected to the roof, there was still quite some plumbing missing. The filter and calmed inlet add up to hundreds of euros. In my case the way the tubes were connected to the tank made off the shelve filters unusable, so I opted to DIY everything.

Rainwatertank Level Sensor

Mechanical sensor parts assembled with a very short sensor tube to fit the picture.

This project idea scored 3/3 stars, combining electronics, water and creating something from scratch. I couldn't resist building my own reed switch array water level sensor.

This kind of sensor has a floating part moving up and down a sensor tube.

It's not an off the shelve solution to sensing water levels, buying a water pressure sensor or an ultrasonic level sensor would probably be easier, but DIY is fun!

My goal was to do some electronics and 3D design, 3D print, experiment and get a circuit board fabricated. I'd build a sensor using easily obtainable parts whenever possible. The electronics should be easy to build at home.

I will use it to monitor and log the water level in Home Assistant. Getting to automate the adding of a minimal amount of tap water to the tank during the summer will be a useful feature.

(dir)VimDiff as GIT difftool

Tig blame + VIM showing all files of a GIT commit in diff-tabs using dirvimdiff

I configured GIT's difftool command to show the changed files as diff-split file tabs I can easily cycle through by pressing gt.

This makes for a good terminal-based meld/beyond compare/... alternative.

Combined with Tig, it allows to quickly inspect a GIT commit's modifications in file context, let's take a look at the quick and simple steps to set it up.

Podcast downloading with Python and systemd

My favorite radio show airs on Sunday afternoon, and often can't listen to it live. Fortunately the radio station offers a podcast feed so I can catch up and listen to old shows. I set up a systemd user timer (cronjob) on my Linux computer that runs getpodcast to download updates.

MR1 'robot' platform build

I printed this miniature cart/robot to show my son I can use my 3D printer and electronics hobby to build things he too can enjoy.

Heater-on-light tracking using Home Assistant

Living in a house with Aterno resistive electric heating, I wanted to get a feel of how our thermostat settings and outside temperature impacts our electricity bill.

I did not want to change the electric installation to add invasive interfacing like current sensing, and hacked a ZigBee door sensor to report on the heater's status LED.

Snapcast Bluetooth speaker on Debian Sid

I use a Raspberry Pi to drive two sets of speakers using Snapcast. To maximize the range of my Bluetooth speaker, I bought a Realtek RTL8761B-based USB Bluetooth dongle with a large antenna.

To get the Bluetooth dongle to work with the latest kernel drivers and bluez-alsa, I had to abandon Raspbian Linux and use the latest Debian Linux instead.

Home Assistant Multi room audio setup

I was able to cook up a fun audio setup controlled and automated with Home Assistant! It features

• Multiple room synchronised audio speakers (fixed/analog, portable Bluetooth devices and via app on phone or tablet)
• Playback of internet radio, Spotify streaming and local audio files.
• Sound notifications for Doorbell, garden gate and other sensors and home alarm events.

In my setup, a docker container running on the Home Assistant machine takes care of retrieving audio from Spotify, internet radio streams and local storage.

Physical devices like raspberry pi's or an Android phone/tablet use a snapcast client to use drive speakers.

openHASP touch display build

openHASP running in a 3D printed case

I discovered openHASP while I was searching for projects integrating touch interfaces with Home Assistant.

It's easy to wire up a cheap ESP microcontroller board and TFT display module, and by loading this opensource firmware you can turn it into a network connected touch control panel and control devices and display things.

When I bumped into a nice 2.8" TFT Desktop stand enclosure on thingiverse, I remembered I had an unused 2.8" ILI9341 display with resistive touch layer from a previous project.

Connecting the dots... I had all the necessary parts in my workshop, this would make a nice project to make over a weekend evening.

lighting scene / mood control proof of concept

Lilygo twatch 2020 running simple lighting scene (mood) control proof of concept

I discovered a lovely smart watch development platform; the Lilygo t-watch 2020. It's an ESP32 based hackable watch, with a small capacitive touch display.

I had already played with the idea of building a small home automation control and status display that fits into the existing switch cover plate, so clicked the order button and leveraged the open source watch firmware to quickly hack together a proof of concept.

Openscad: Interlocking Hash shaped platform

While designing a screw-drive based RC tank (perhaps more on that later), I wanted to create a large easily customisable support structure out of a minimal amount of plastic. I started prototyping an interlocking structure in the shape of a octothorpe (#). This turned out to be a lot of ugly code, and so I got sucked into rabit hole of optimising my openscad model and found a cleaner solution.

Home assistant based automatic alarm

image: cover from https://mzl.la/ihr-nov-2019

At one point I wanted a basic home security system (burglar alarm) to offer me some peace of mind at night.

My Home Assistant instance has enough sensors to figure out what we are up to, so it was possible to create an alarm system that works autonomously. The system automatically arms and disarms while we sleep during the night and when we leave and return to the house during the day.

Reviving my Standing stats project

I have used an Ergotron standing desk for 5 years, then it broke, right out of warranty. Several years ago I started building a sensor device to track how much time I spend standing up versus sitting down in my chair. The hardware prototype finished, it got shelved since I found other fun things to do with my limited hobby-time.

Later I noticed that I was sitting down 99% of the time when working from home. To revive my healthy habit of working upright part of the time, I decided to pick up my parked project by re-printing the enclosure I made on my own printer and leveraging the power of esphome on and home assistant to finish the project after all.

owl-filament.de review

I read on Facebook someone bought low-cost filament from http://www.owl-filament.de/. I'm always interested in alternative sources of filament to use with my 3D printer, so I took a look.

I already had a limited set of PETG spools in nice colors and was interested in some cheaper spools for prototyping purposes. The price was 'cheap' indeed, read along to see how this manufacturer's quality turned out to be...

ILI9341 SPI TFT on the raspberry pi4

I've been running network services on embedded arm platforms for for more than 8 years now, and when things go wrong, had to drag around HDMI monitors to hook up. For the last years I had a pi connected to the serial console to avoid that.

I have been mounting all my networking and smarthome devices on a DIN rail, and I had some small 2.2" TFT displays around for a different project.

I thought it would be nice to create a raspberry pi enclosure that included such a display so there's a real video console on the device that can also be used as status display.

Din-rail mounted Home assistant gear

I have a technical wall with several pieces of electronics mounted onto it. It started to look a bit disorganized, with all these things mounted at random places on the wooden board and cables running all over the place.

So I wanted to clean it up a bit... I stumbled upon a DIN-rail mount on Thingiverse, and remembered I had a piece of DIN rail in a box. Time to remix a bit and mount everything on DIN rail!

Networked USB scanner

I have a USB connected flatbed scanner, a Canon CanoScan LiDE 110. I need to use it more frequently these days, and figured it would be handy if I connect it to my office-rpi and use it over the network.

Board stacks

At home and at work, I always tend to have around 5 small development boards on my desk. In a fixed setup with identical boards, metal or plastic standoffs can be a nice solution to build a stack that reduces the footprint on desk and avoid a spiderweb of cables.

In reality, the boards are of different sizes, and standoffs still cost a few euro's each. I knew I could do better, using a 3D printer and some parametric CAD modeling.

TV Console corner protector

During COVID19 lockdown, the kids were running around the living room a lot more, and a lot more reckless. Our TV console is covered with glass plates. These have chamfered corners (45 degree cut off), but still it's a hard, glass corner, and I could imagine painful or catastrophic injuries and trips to the ER.

I decided to create a quick and dirty cover that, once installed, would provide safer plastic, rounded corners.

DIY extension block

During COVID19 lockdown, I found myself struggling with cheap extension blocks, in fact I find most extension blocks horrible, and most power supply blocks can't fit next to each other.

I still had three brand new, wall sockets left over from electricity renovations (I opted to place earth wire so installed appropriate sockets). These are Niko brand, the finest EU/BE sockets available, and are lovely to use in every way possible. I already considered making larger extension blocks this way.