Sylvain DOIGNON

Air Quality Monitor

Still on my quest to stay healthy, I have been interested in air quality for years. This led me to take a closer look at the air quality sensors available to the general public and I was really disappointed by their quality compared to professional sensors, which drift far less over time.

It was also a simple way of starting another electronics project with a chip I had never programmed before, which is obviously the ESP32. All of this was made very simple thanks to Sensirion, a brand that makes a whole range of sensors I am particularly fond of. I bought their brand new SEN69C, which can measure particulate matter (PM2.5 and more), CO2, VOC, NOx, formaldehyde, temperature and humidity.

My goal here is twofold: I already built a version in the past with a SEN66 on a more or less similar board but with Stemma QT connectors. This time, I am much more interested in keeping the setup as simple as possible, so that it also stays cheap. Indeed, my goal is to create an MVP, because I care deeply about air quality and I think people simply aren't aware enough of it. Beyond just having a very good sensor at home, this is the start of a project aimed at commercializing a product that I believe could sell cheaper than the alternatives while being of better quality.

N.B.: component list: Seeed Studio XIAO ePaper Display Board EE05 + Seeed Studio 2.9" Quadruple Color eInk + Sensirion SEN69C

I bought this domain more than five years ago and I had always wanted to make this game as a mobile app, because this game is just so good (but can be impractical to set up). In English, this game is known as Fictionary (or Call My Bluff/Balderdash). To keep it short: someone picks a complicated word, presumably unknown to everyone, from the dictionary; everyone then writes a plausible definition, and the one who chose the word has to get the others to guess the real one among the fakes written by the players.

The problem with this game is that it requires a physical dictionary, which has become harder and harder to get hold of unfortunately. It also needs paper and pencils, which always takes a little setting up. And reading some people's handwriting can sometimes be a challenge (I am the main culprit myself). Last, the shape of the paper slips and their folds make it possible to cheat a bit. In short, it was a perfect candidate for a digital adaptation.

What also mattered to me was to explore fully local communication for a web app, that is, not going through the Internet. All the players have to be on the same network for it to work, and the exchanges stay on the local network only. I found this quite interesting from a technical point of view: I wanted to know which technologies make that possible, and how to orchestrate the app so that it works.

The game itself was really interesting to make, as I spent a huge amount of time writing a very detailed plan with the help of an AI so I could really feel like the author of this project. The implementation was done by AI. Nothing was left to chance regarding the design, and the same goes for the language, the design patterns, the communication, etc. I am quite proud of this way of working and actually feel it's my app.

And now, it is time to play (have not actually done it yet)!

I have hundreds of YouTube subscriptions as I have quite varied hobbies and interests and I was losing a huge amount of time watching YouTube... It had become impossible to consume everything, so some videos were simply getting lost, even though they could have been interesting. The real goal of this project is to decide which videos are absolutely worth watching and just get a small summary of the others. It lets me keep track of all these subscriptions and decide exactly how much time I should invest in watching each video.

This little project fetches all the new videos from my subscriptions, retrieves the transcript from the YouTube API (or performs speech recognition when that isn't available), reformats the title so it is uniform, and then feeds the transcript to an AI to get a summary, the best moments, and the conclusion. There is also a feature to chat with the transcript, to ask precise questions.

What mattered to me was to have no external dependency: all the AI runs locally on my Mac. I've been using it since I created it and I'm very happy with it. It feels much more like I'm watching what I need to watch, while keeping an eye on the rest.

It's a really great source of information, on top of my secret weapon for many years: reading a large number of sources via RSS!

Monitoring airplanes with radio

I finally took the plunge into the software defined radio world, something I'd known about for years since my visits to la Nuit du Hack, but which I had never really experimented with. The trigger was my move to a new place with a lot of airplane traffic overhead: the perfect spot for a little ADS-B receiver! I was amazed by how little investment it takes to get something up and running (of course I did buy a dedicated antenna which doubled the initial cost). I've always had a certain attraction to aviation so this was the perfect project to dig into SDR + airplanes. It feels like magic when you're picking up the airband and listening to conversations between aircraft and the control tower.

My little ADS-B receiver (connected to a Raspberry Pi) now shares on several online networks contributing to the global coverage of ADS-B. Not sure it's actually needed near London... This project has taught me a lot about radio: the technical side and the practical side, like antenna positioning!

This is certainly only the beginning of other radio projects to come.

I rely on hardware security keys and a password manager for my passwords. At some point I asked myself two simple questions: if my password manager were to disappear tomorrow, how would I retrieve my passwords? And what if I disappear, how could my family gain access to my online accounts? My passwords definitely needed a safe and smart backup.

I've done some research and landed on Shamir Secret Sharing, what a beautiful piece of algorithm! Basically you split a secret into parts and you only require some of those to recreate it. That was just perfect for my use case. I just had to bundle this up in a single static web page: very easy to store long term, it has no dependencies, only requires a web browser, and is very portable.

For my purpose, I give each secret share to a different trusted person with instructions and the decrypting page - it's in French since most of my friends and family read it. Each of them also knows the other secret share owners, listed in the instructions. It's as simple as that!

To make the whole thing resilient and portable, each secret share is rendered as a series of short French words from a custom 256-word list, so they can easily be written down.

I actually use this tool and rely on it. That bought me some peace of mind!

Misc. Smart Home Projects

Many things are connected in my house, and the brain of it all is Home Assistant. Over the years, this hobby has made me practice electronics as much as networking, taught me a lot, and brought me plenty of satisfaction. Here are a few highlights.

One of my first achievements was to connect my water heater. It may not sound fancy, but it was a real pleasure to have it under control: I could switch it off whenever we left for holidays and turn it back on one day before coming home. Hot water on arrival, without wasting energy while away. Perfection.

But the most interesting project was to "smartify" a 90s fuel-oil boiler. It was obviously not designed for that and its wiring diagrams were nowhere to be found online. I had to do a bit of electronics to connect it so I could control it from Home Assistant.

On top of it, I built a whole thermostat system: I installed a bunch of temperature sensors in the different rooms plus an outdoor one. They let me fire the boiler at the right moment to have the ideal temperature when waking up, while stopping it early enough to avoid overshooting the target temperature. The system also factors in the outside temperature to guess whether the heating will be fast, or whether the house will lose a lot of energy, all to have the best and most efficient heating schedule. It was so much fun to build, and I'm pretty sure it saved us a good amount of fuel.

My home network runs on semi-pro UniFi gear: a router, switch, security cameras, etc. This taught me a lot and gave me a real playground to practice network segmentation. And what a pleasure to have cameras processing and storing footage locally. Plus plenty of other sensors to trigger smart automation workflows!

I've also been using Philips Hue bulbs for years. Doing all this for so long gave me a clear idea of what I would change if I were to start from zero: probably not using connected light bulbs, but connected switches instead.

Anyway, that description is probably out of date already. But the lovely thing about a smart home is, it really motivates you to build something robust, since spending unwanted time on it in the evening is really not what you want - but what you end up doing sometimes!

I needed to create a complete online solution to manage remote Yoga lessons.

That meant a website to welcome visitors and a way to book available lessons. A payment integration was also needed with refund, postpone and cancel options. But also a mailing solution to batch send Zoom links when a lesson was about to start and some customer insights on the platform. At last, all this needed to run cheap : it was cheap indeed, I made all this work for free.

The easy part was the website. I used Jekyll since it's available with GitHub pages, which are free to run. The website being mainly static, this was an obvious choice. The website is responsive and lightweight to maximize user conversion.

Then, I created an "admin dashboard" to create new yoga lessons. This part is not available publicly on my GitHub. Basically it's a AWS Cloudformation stack with an API Gateway, a DynamoDB database and some Python Lambdas. When connected to a well-known URL, one can create new lessons. On submission, the Zoom API is called to create a new scheduled meeting, Stripe is called to create a new product and a new entry in DynamoDB is saved. At this point, this lesson is now displayed and bookable on the website (lessons are queried via the API).

When someone book a lesson, we collect the payment via Stripe in a few clicks (the Apple Pay integration was convincing). When the system receive the Stripe confirmation callback, a transactional confirmation email is sent. In this email, this user receive his private account link which he can use to manage his lessons. He can postpone any lesson to another open booking, credit his account when cancelling one lesson (so his next booking is free or discounted) or ask for a refund. It was essential to empower the user so all those actions were available in a few clicks with no hustle.

This was a fantastic project, well used during the 2020-? stay-at-home period. So many technical bricks were necessary and exposed to real users with real money : everything needed to be optimized and polished. And thanks the power of serverless and careful pick of integrations, this stack practically runs for free. Overall one of the nicest personal project I ever did for sure.

View the website

This project was born when I occasionally needed a VPN. Having played a bit more with AWS and Cloudformation, it was the perfect time to use it for personal projects.

Consisting of a single Cloudformation file, this stack creates a S3 bucket, some Lambda functions and an API Gateway. The API Gateway statically serves under a well-known path a web page. When entering the correct password, you land on the VPN on the Go dashboard when you can see available VPNs. Every VPN is a EC2 instance configured with softethervpn offering L2TP/IPSec PSK and OpenVPN connections, supporting a large range of clients. To ease the OpenVPN connection, the client configuration file is available to download from S3. Since I usually only needed a VPN for a few hours, an auto destroy option is available : the EC2 instance and all configuration could be erased automatically after a certain time.

This project was very fun to create and helped me a lot. Being able to easily create on the spot VPN instances with new IPs for cheap always seemed like magic.

I just brought a new toy : a SensorTag. This little bad boy is able to record a lot of metrics like temperature, humidity, pressure, etc. I wanted to save those metrics and present them in a nice day. Furthermore, I wanted to add weather and public transport information as I did in a previous project, and some lights control.

That's why a created some Dockerfiles to, first create a Node.js app gathering metrics for the SensorTag every few minutes and storing them in a database, an API able to get those stored metrics and pilot my Hue lights, and finally a web app to expose all this.

I created the web app with React to try this new fashionable library and found it very compelling. InfluxDB was chosen for this thanks to its ability to handle metrics, even though everything remains quite basic.

My Raspberry Pi was running this and I ran the web app on an old tablet, it was beautiful and made good usage of the SensorTag !

I now inherited a new email address, a Office 365 one for work. Having no official Office 365 email app on Linux prevented me from getting notifications when receiving new emails. I didn't want to rely on the web app since (at the time) the Outlook browser notifications were not very reliable and I would have to open my browser and the Office 365 to tab to get it working at all time.

That's why I created a straightforward Gnome Shell extension to notify me in the taskbar when received a new email : problem solved.

My previous CV was made with Photostop. Every edit was a nightmare: boot up a Windows VM, open the bloated Photostop, make the edit, re-align all the content, flatten all the layers, export it with the correct parameters... Furthermore Photoshop is not free as in speech or as in beer.

That's why I decided to make the same CV but with LaTeX which is a professional document preparation system. Basically, you declare the general layout, the content and LaTeX does all the formatting part. This is great! No more time is wasted on the layout.

This was my first real LaTeX document and I used the great moderncv document class. I only disliked the header layout so I made one myself.

Now, editing my CV is really easy. Fire up a text editor, make the edit and compile in seconds the corresponding PDF.

Created to explain and present my projects in a more practical manner that GitHub does.

Made from scratch, easily editable & hosted on GitHub.

This website is defined by meta-language, such as LESS & Pug who compiles respectively to CSS & HTML. This allows the code to be as small as possible and very modular. Furthermore, when in development, I've added a watcher on some files to automatically launch the build process. In this way, there is no "build time" drawback.

Code strive to be minimal. This project permitted to acquaint myself with the relatively new CSS flexbox positioning system.

I always dreamed about a screen always on presenting some useful information. The low energy small laptop WM8650 from a previous project was a perfect device for this.

This device can't host an X server with good performance that's why a fancy way to create such a dashboard can be a terminal app. I've chosen the Go termui library to learn the Go language.

Extra, nobody likes to miss a train because it left just a few minutes ago. Also, the general train status is important. When all trains are cancelled because of an outage, it's better to anticipate. Furthermore, everybody likes weather forecasts. That's why I wanted my app to display all this information.

For this, this app fetches some information from the RATP & the Open Weather APIs.

The dashboard displays the following info :

• Trains status
• Next trains
• Next bus
• General day information
• Weather
  • Temperature
  • Cloud coverage
  • Wind speed
  • Rain

You can also control the house's light bulbs thanks to the Hue system.

This device is now used everyday and is very convenient. I never missed a bus or discovered a cancelled train while in the station!

This project was my third Android app but the first really useful one: this app fetches and present the NASA's Picture of The Day.

I started this project for a school project intended to learn images gesture on Android. But instead of the dumb and useless app requested, I wanted to make this app useful. Therefore, I pushed the instructions further and came with this idea of presenting beautiful images (with gestures support, of course) but along with other features. Such as:

• Fetch the last two NASA Pictures of the Day
• Create a date picker to view a past picture
• Open the related NASA website
• Share the app with your friends
• Great UI?

This app has been great fun. I still have the app on my phone to learn space things and this app is often downloaded by people all around the globe.

My second Android app was very educational and kind of useful. In fact, this app is the classic TODO app.

This app manages notes. Each note can have a deadline and a priority. Then, you set the task as "done". The main view allows the notes to be sorted by numerous criteria.

This project permitted to learn the intent, activity and list view objects in Android.

This is a school project. The instructions were to make a temperature converter with a UI app as simple as possible. That's why there are no buttons but only two fields that convert automatically the number you input.

This app permitted to discover the Android development that I always wanted to discover.

This is one of my favourite challenge/project.

While friends were about to throw away this antique Android-only laptop (useless to them), I recovered this laptop challenging myself to install Linux on it.

First, this Chinese small laptop had one of the first release of Android : Froyo. It was painfully slow on this device and not usable at all: who support Android 2.2 nowadays?

As i said, I decided to make it run Linux! The possibilities could be endless after that. This device uses uboot as a bootloader and supports booting from an SD card. Luckily, the architecture armv5 is quite common. I managed to find a great OS for it: ARM Arch Linux. Others had done this before but with older kernels. So I had to to cross compile a kernel, reboot by reboot, option by option to get this device up with the latest version of ARM Linux & the Kernel (4.7 at the time).

This has been great fun. I learned a ton about the kernel and the ARM architecture. And more importantly, this device is now useful! It has a fully working ethernet port, 3 USB ports, WIFI, small screen and keyboard!

I love to tune everything to the perfection for my usage. So, after hours on various things (Zsh, Git, etc.) here's my dotfiles.

More info coming soon.

My first text editor was Sublime Text. I still like it. However it's not an open-source software and can't run in terminals. I always knew about Vim & Emacs but wasn't appealed by the apparent complexity and change.

When I had to edit a lot of files in terminals, I got tired of nano. That's why I managed to make Vim behave like Sublime Text. The MiniVim project was born.

I spend hours creating the most awesome vim configuration I could. That was very instructive. I discovered Vim a lot. The project is now quite big and complete and Vim is now much more intuitive for Sublime Text newcomers.

I use this tweaked Vim everyday at work or at home.

After Korben.info made a post about it, people took interest in the project and I had to manage it like a real small open-source project: issues, pull-requests, forks, etc.

This is my most successful project yet with over 270 GitHub stars.

For a school project, we had to realize a website with a great UX. We didn't wanted to create another useless website so we ask around the university who wanted a new website. Graf'hit radio answered first.

We decided to develop the website using Node.js that I have been experimenting with a bit. At this occasion, I improved my Node.js skills and was my first website created with Node.js.

One interesting requested feature was the fact that you should be able to navigate on the website without the current audio stream interrupted. That means you can't just change the page when the visitor click a link but you have to dynamically update the content using Ajax.

This website has some great features and got myself to know about audio in HTML5: real-time, replays, etc. It was impressive and empowering to design a website for a real usage, a radio.

Source code

I wanted to find a fun project for an evening and learn more about SVGs.

That's why I created a website recreating this old Windows XP screensaver which bounce a triangle across the screen edges.

Source code

Following my Human2Cat language experiment, I wanted to be able to translate text on the fly in the browser. Furthermore, at that time, I never wrote a browser extension.

When a text is selected, with a right-click or a hotkey, you see the translated text. When the selection is in an editable field, the content is replaced by the translation.

With this project, I discovered the Chrome extension API which is quite good in my opinion. This experiment is small but improved my knowledge about browsers.

This extension is now published on the Chrome Extension Store, I'm a happy man.

Fascinated with ciphers, I wanted to create a small and fun one.

This program can turn any text into a "cat language". => grau, mio, Mio, Miaa, mi mia, miaa, Miouu, Miuu, miaa, Mi, Miou, mi Mii, Mi, miouu, mi miau, Miau, miaa, miouu, mi Mi, miouu, Miao, mi miau, Miu, miao, miau, mi Mio, miouu, miau, Miouu, mi Mi, mi mii Mii, Mi, miau, mi miou, Mi, miouu, Miuu, Miau, Mi, Miuu, Miu, mii miouu

Then, you can convert it back with no information loss whatsoever. It's not encrypted at all, it's basically just a fancy way to store 8 bits (that way, all UTF-8 character sets are supported).

Source code

Java is, for now, not my cup of tea. However for a school project, in a group of two we had to make a website with Java EE.

This website is KickStarter or IndieGogo basic copy. I knew nothing about Java EE at first so I learned a lot that way.

I wanted to know how much I made in an hour, in a day, etc. I found no websites doing so.

Of course I could just grab a calculator. But, I can't be the only one wanting to know this: someone had to do it.

Source code

My laptop has a high resolution for its screen size. That means, sometimes, I can't read the texts because it's too small. In this was, I used xrandr to "scale" the display to a lower resolution.

But this solution needed to open a terminal and type something and was not very convenient. That's why I decided to add a shortcut to "toggle scaling/zoom" in my desktop environment ; Gnome Shell at the time.

My extension creates a small icon on the top right corner of the screen which is able to toggle the scaling. This worked and no more terminals were opened to change the scaling factor from this day.

I have an external monitor. I frequently change the brightness with the buttons under the monitor. However, this is not convenient and fast.

The DDC protocol exists to control the monitor settings through HDMI. That way, using a command line program, I was able to set my monitor brightness. Still, that was not enough fast and intuitive.

That's why a created another Gnome Shell extension that pop up a small window with a slider to change a monitor brightness. That way, I was satisfied.

For a school project, in a group of two we had to develop an C++ Qt Calendar application. That was the final project for a fascinating C++ course.

Features requested were;

• Display week days
• Create projects with corresponding tasks
• Meta-Task can be created to gather sub tasks
• Each task has a start date, an end date, etc.
• Export all the projects
• Create reminders

I took this project very seriously and I wanted to make the best app possible. Both code side and UI side. I worked hard, discovered Qt in depth to create this app.

Finally, we had the best grade for this app and we learned a lot.

The SSO of my University forbids the web browser to remember credentials. While this is mainly a good idea, on my personal computer this is a struggle.

For this, I created a bookmarklet (a special bookmark that embeds Javascript code) to solve this problem. When you click on this special bookmark, it will redirect you to the SSO website if you're not already there. Then, it will automatically submit the form using your credentials.

As always, I like to share and help others. That's why I created a small website to allow everyone to create their own login-bookmarklet.

This website was a success was used by other students!

In summer 2014, my friends and I went on a long trip across Europe hitchhiking. That was amazing. Before we began, I wondered how we could give news to our families.

Using our email address were not an option because it would be dangerous if we logged on a shared computer. Furthermore, we would be sentenced to include a long list of all the people we wanted to share news with.

That's why, we needed a website to post news. However, CMSs at the time were not very mobile friendly. So I had to develop a mobile-centric one!

• The website is very small in size
• The configuration is minimal, simply create a folder with each member you want to create
• You can write articles easily, even on mobile. You can join pictures

During this long trip, this website was heavily used. Our parents loved it and we could share the address of this website to the people we met. That was a success!

In my University, viewing the timetable was a nightmare. You had to click 7 times and log in every time. That could not last.

This was my first real project. In a nutshell, this website scrapped the Timetable server. Then, it parses the special files received. Then, it populates a database. Meanwhile, a website allowed to view the timetable very easily and... beautifully.

This project was a huge success. I started this website only for my personal convenience but soon lots of people in my class, then in other classes, used it.

I made two derivatives.

Piwake, the original

Piwake Lite, a lighter version that only needed Javascript and fetched the timetable "live"

Austra, or a project directed by the University itself to replace the original viewer including other enhancements.

This project was a ton of fun and very instructive. Having a website used by other people raised real world problem like availability (my Raspberry Pi sometimes crashed because of the unstable current).

At that time, I lived in a family in Bordeaux and have to count my meal I took with them to pay them at the end of the month.

First, we had the "sheet of the fridge" system. It worked but was sometimes forgotten and you had to sum up at the end of the month something that a computer could do.

Also, I learned PHP in school during that time.

That's how my first PHP project was born: PiMeal. A small PHP page with a button on the bottom "Add a meal". Afterwards, depending of the time of the day, the meal would be stored in a database. And the global counter on the bottom was always up-to-date.

After that, it was a pleasure to add my meal and see how my app was working well!

My Raspberry Pi.

This was the beginning of a long journey (not yet finished) of various projects. I learned a lot about Linux and Internet thanks to it.

In fact, it was connected to the Internet and I brought a domain. Then I set up a dynamic DNS because it was hosted behind a non static IP router.