fosdem – Terence Eden’s Blog

OpenBenches at FOSDEM

@edent — Sat, 21 Feb 2026 12:34:03 +0000

At the recent FOSDEM, I did a very quick lightning talk about our OpenBenches project.

Sadly, despite the best efforts of the AV team, the video had a missing section. I took my own audio recording and zipkid took some photos, so I was able to recreate it using the Flowblade video editor.

Enjoy!

Many thanks to Edward Betts for running the dev room and providing the display laptop.

The cost of running OpenBenches.org

@edent — Tue, 03 Feb 2026 12:34:16 +0000

After my recent presentation at FOSDEM, someone asked a pretty reasonable question. What does it cost to run OpenBenches?

It is, thankfully, surprisingly cheap! In part, that's because it is a relatively simple tech stack - PHP, MySQL, a couple of API calls to external services. It was designed to be as low cost while also being useful. Here's the breakdown:

Hosting - £171 per year

Our biggest expense but, I think, our most reasonable. Krystal charges around £342 for a 2 year contract. That includes unlimited bandwidth and storage, as well as the domain name. We have nearly 400GB of photos and bot scraping means we can use over 900GB of bandwidth per month - so Krystal give us a rather good deal!

Use this affiliate link and code EDENT to get a small discount.

Stadia Maps - US$20 / month

Geocoding is surprisingly hard to do locally. We need to transform latitude and longitude into addresses, and then back again. Stadia Maps cost about the same as our hosting! What's rather annoying is that we only use about half the API calls in our plan. We need to find a cheaper solution.

Mapping - Free!

When we used Stadia for drawing maps, we regularly ran over our quota. So we switched to OpenFreeMap which produces gorgeous interactive maps.

The service has been rock solid and very responsive to bugs on GitHub.

Logo - US$5

I'm not a good designer, so we bought a logo from The Noun Project and then coloured it in. Bargain for a fiver!

Image CDN - Free!

Although we have unlimited bandwidth with Krystal, we're only located in one region - the UK. WeServ. It's also pointless serving full resolution images to small screens.

So WeServ offers free image resizing and global CDNs. Personally, I'm not a fan of CloudFlare (their CDN partner) so I'm looking to change provider.

OCR - Free!

People don't want to type in the inscription of the photo, so we use Google Cloud Vision.

We send less than 1,000 requests per month - so we're inside their free tier. If we get more popular, that'll get more expensive. But I don't know of a local-first OCR which is as good as Google's. Sadly, Tesseract is rubbish for extracting text from photos.

Authentication - Free!

We don't want to store anyone's passwords. The free tier of Auth0 allows us to do social login for up to 25,000 monthly users. Which is more than enough for us.

Sadly, Auth0 don't support the Fediverse, so I had to build my own "Log-in with Mastodon" service.

As much as we'd like to run social login locally, we simply don't want to be responsible for securing users' details & API keys.

Software - Free!

As per the OpenBenches colophon we use a lot of cool FOSS. Small JS libraries, big PHP frameworks, and everything in between.

Income

Thanks to GitHub Sponsors we make a whopping US$3 per month!

Similarly, our OpenCollective Sponsors brings in about £3 per month.

Merchandising! You can buy OpenBenches branded t-shirts, mugs, and hats. That nets us about £20 per year

Call it roughly £80 income. OK, it is better than nothing - but doesn't even cover a quarter of our costs. Sometimes people give us a higher donation privately, which is also very welcome. These people are listed on our README.

Total

On the assumption that our time is worthless (ha!) and that we only rarely go over our providers' API limits, and we get in some revenue, the cost of running OpenBenches is less than £300 per year.

That's not bad for a fun little hobby. People certainly spend more than that on Funkopops, vaping, and mechanical keyboards!

Nevertheless, I'm always slightly worried that we'll go viral and have an unexpectedly high bill from our API providers.

I would love to be able to hire a proper designer to make the site look a bit nicer. I also want to be able to buy a modern iPhone so that I can test it in the latest Safari.

If you have any suggestions for cutting costs, or non-scummy ways to help us raise funds, please drop a comment below.

Presenting ActivityBot at FOSDEM

@edent — Sun, 09 Feb 2025 12:34:17 +0000

Because I'm an optimist, I submitted a few talks to FOSDEM in the hope one might be accepted. Because I'm lucky, I got two speaking slots. Because I'm an idiot, I decided to do both talks. On the same day. An hour apart. On opposite ends of the venue.

Fool!

My first talk was at the Social Web Birds-of-a-Feather session. I told people about my ActivityBot social networking server and how I built it into a single file. In the spirit of minimalism, I only had 8 minutes to present. Time for a speed-run!

Sadly / Luckily there's no audio or video of the session (if you have some, let me know) so you'll have to make do with some slides. Speaker notes are included - read them rapidly for the full effect!

I built an ActivityPub bot server in 64KB of PHP. Sorry!

Feedback and Photos

Review: Voviggol Finger Ring Presentation Clicker ★★★★⯪

@edent — Fri, 07 Feb 2025 12:34:10 +0000

I was packing for FOSDEM when I suddenly realised that I'd lost my clicker. Disaster!

Here's a shortlist of what I need in a presentation remote:

Ring style to fit on my finger
USB-C
Works on Linux
Frickin' lazor beams!

The only one I could find which matched all that was this Voviggol unit.

Ring

Here's how it looks hooked to my hand:

The ring is stretchy and will fit around the thickest thumb. It grips the finger tight and didn't fly off even when I was gesticulating wildly.

USB-C for everything

It uses USB-C for charging and comes with a removeable dongle which has both A and C connectors. The dongle attaches into the clicker with a magnet.

If you connect the clicker to a computer to charge, it doesn't show up as a device.

Linux Compatibility

On Linux, the dongle shows up as:

1ea7:1066 SHARKOON Technologies GmbH Wireless Present

It worked with both USB-A and -C, and showed the same information.

Android

It also shows up as a keyboard on Android. Mostly useful for if you're reading a book and want to flick through the pages without using the touchscreen.

Connecting it to Android will temporarily show a mouse cursor on screen. Running evtest on Linux shows the device presenting as:

/dev/input/event18: Wireless Present
/dev/input/event19: Wireless Present Mouse
/dev/input/event20: Wireless Present Consumer Control
/dev/input/event21: Wireless Present System Control

So a fairly generic dongle, but with a restricted set of inputs.

LAZORS!

Press big button. Red beam of light. Attracts cats. Nice.

Buttons

The left and right buttons can be reprogrammed. By default, a short press gives you page up/down and a long press gives you volume up/down.

The top button is screen-blank (it literally sends the letter "b").

The bottom button is odd. The first time you press it, the device sends esc. The second time you press it, Left Shift + F5

Personally, I'd've preferred if the remote just had larger left and right buttons, but I guess the others are kind of useful.

All buttons worked on Linux and Android.

Change the buttons

Press and hold < and > for 3 second and the clicker will swap between 3 modes:

Up / Down
Left / Right
Page Up / Page Down

There's no way to change the other buttons.

Interface

There's a tiny and somewhat flimsy switch on the side to turn it on or off.

A little LED goes red when it is charging, and flashes blue when you press a button. Fairly unobtrusive.

Distance

I didn't formally test how far away it worked, but I pranced around the stage in a noisy radio environment and the 2.4GHz radio worked just fine.

Is it encrypted? Dunno. Probably best not to leave it plugged in all the time.

Verdict

For £20? Basically fine. I prefer ring-style presentation remotes because they let my flap my hands without losing the controller.

The buttons are a smidge small, and you'll probably forget how to reprogram it. But it does the job well. It came with a comically short A-C charging cable which was immediate e-waste.

Let's hope I don't lose this one!

Talking Contact Tracing at FOSDEM

@edent — Thu, 06 Feb 2025 12:34:19 +0000

I was delighted to be invited to speak at FOSDEM. And I was not at all intimidated to be speaking on the cavernous Janson stage. The audience were lovely⁰, asked interesting questions¹, and - most importantly - laughed in all the right places 😅.

Regular readers will recognise this as being an updated² version of the talk I gave at EMF 2024 - feel free to watch that one if you want to see if I've improved.

Huge thanks to the AV team and the video-wizards behind the FOSDEM infrastructure.

As I say in my introduction, these are my personal recollections. I no longer work for the Government, so feel free to send any complaints to the circular file.

Feedback

A few pieces of public feedback I got after the talk.

Except for one weird heckler who shouted out something incomprehensible. ↩︎
Well, one guy came up afterwards and asked "What exactly is Covid? Can you explain?" I politely suggested he speak to a medical professional. ↩︎
But, yes, still wearing the same t-shirt! ↩︎

FOSDEM - The Good Parts and the Not-So-Good Parts

@edent — Wed, 05 Feb 2025 12:34:31 +0000

I'm just back from my first ever FOSDEM - a megaconference dedicated to Free and Open Source technology and culture. It was epic. I'm still ruminating on the experience, but here are my first impressions of what did and didn't work.

The Good Bits

Really, it is a dozen conferences squeezed into one. Over a thousand talks, on a seemingly infinite array of subjects, about a million people crammed into one tram from Brussels city centre, and a panoply of wonderful humans with crazy ideas on how to change the world.

Every single talk I went to was interesting, the conversations in the hallways were friendly and entertaining, the vegan food wasn't too overpriced, and I only met one crypto-bro.

The speakers were reasonably diverse and - get this - young! It sometimes can seem like FOSS is dominated by greybeards but, so it appears, the future is in safe (albeit annoyingly youthful) hands.

It is obvious that a great deal of care an attention has gone in to making it a welcoming and safe environment. Most rooms had information about the code of conduct. Old universities are hilariously inept at providing maps, so there were helpful signs up everywhere. Even the toilets had QR codes so you could let volunteers know if there was a critical shortage of paper!

The volunteers make the event. Each one I spoke to was friendly, helpful, and knowledgable. The event (mostly) ran like clockwork and shows what a determined and well-directed team of people can do if given sufficient motivation and autonomy. (I did my volunteering before the event by fixing bits of the website.)

Overall, an excellent experience. Mostly.

The Not-So-Good

Look, it's a volunteer run event which successfully handles ~9k attendees and > 1k talks. These are all fairly minor snags. But, as a first time attendee, there were a few things which rankled me a bit.

Venue

The biggest issue is Université libre de Bruxelles. The university is very dilapidated. The seats are uncomfortable, the toilets are grim, and many of the rooms are not accessible. Of course, it is a historic venue and there isn't much the FOSDEM team can do about some of the structural issues, but I think they should feed-back to the university where improvements are needed.

Specifically:

Water fountains. As far as I could tell, there was only one working fountain in the whole campus. Several seemed to have been deliberately closed off.
Lifts / Elevators either not working or not available. For example, the community room was up five flights of stairs. That's a challenge for a lot of people, and an impossibility for some.
Windows and ventilation. I appreciate not every room can have modern HVAC, but the CO₂ monitors were frequently in the red. Some rooms had windows which were locked shut. Unacceptable given the risk of Covid and Flu.

I accept that it is unlikely FOSDEM can fix all of these unilaterally. I don't think it is realistic to change location now that it is an established - and much loved - venue. But the ULB needs to be told that its facilities are inadequate and need urgent improvement. To be fair, it probably knows that it has some issues, but I think they are worth pointing out specifically.

AV & Hosting

For the most-part, the AV worked. Yes, people with Macs didn't know how to set up external screens, and HMDI connections occasionally freaked out, but those are all user error WONTFIX.

Some sessions over-ran egregiously. That's disrespectful to the audience (who may need to get to a different session) and downright rude to the next presenter (who needs a few minutes to set up). While that's partly the fault of under-prepared presenters, it is the responsibility of the room host to be ruthless with the timekeeping. I did see a few speakers being told "your time is up, you have to stop" - but not enough.
Some of the rooms didn't have heralds or timekeepers. I'm a bit old-fashioned and think it is nice to have someone say "And now, please welcome our next speaker…" so that the speaker can start with a round of applause. It lets everyone know the talk is starting and to pay attention.
Audio in Janson. I was given contradictory information about whether the main stage would have audio but was then reassured that it would be fine. I then discovered the only way to have sound play from my slides was to hold the microphone to the speakers! I think that's a bit rubbish but it would have been fine if it was communicated to me in advance.

In short, speakers need to be better prepared, volunteers need to be empowered to shut them up, and everyone needs to be told in advance what equipment will be available in their rooms.

Matrix

*sigh* FOSDEM must be full of Matrix's target audience. But the whole experience was underwhelming.

The flagship ElementX app is buggy and missing several crucial features. It gives a bad impression of the service when basic functionality just doesn't work.
There was a lot of confusion with how Rooms (or is it channels? Or spaces?) were set up. Speakers were told to go to one room, then redirected, then re-invited. Confusing and frustrating.
No one was using it! Even in the main channels, there were only a few messages per hour. Nothing compared to Mastodon or Bluesky. There wasn't much pushing of Matrix, so maybe most people were in private Signal / Telegram / WhatsApp groups with friends (I know I was).

Ultimately, Matrix needs to have a serious look at its quality issues otherwise it will become as irrelevant as IRC. Similarly, I think the organisers should decide whether Matrix meets the needs of attendees or if a different platform is more suitable.

Verdict

A simply wonderful event. I was thrilled to be selected to speak, and am incredibly grateful to FOSDEM for subsidising my trip with a hotel room.

My brain is fizzing with new ideas and my laptop is groaning under the weight of new stickers.

I would love to come again next year. Although speaking was great fun, it was exhausting doing two sessions. So I'll probably be a bit more of a tourist.

I'm now off to sleep for a hundred years in an attempt to recover from the intensity!