What I learnt at EMF Camp 2026

Electromagnetic Field ran from the 17th to the 19th of July at Eastnor Castle Deer Park in Herefordshire. Around 3,000 people camped in the field. At 4 on the Friday afternoon a man towed Look Mum No Computer's flamethrower organ across it behind a road legal ride-on lawnmower. While a couple of people took photos, almost nobody looked up.

I was there to give a talk and spent the rest of the weekend walking around. This is what I learnt.

• EMF runs every 2 years. For that weekend the field gets a power grid, a DECT phone network with extension numbers and volunteers running high-speed internet to your tent. The schedule had 550 things on it across 66 venues, a lot of it run by villages, which are camps within the camp. I missed most of it.

• The Flame village was down by the lake. Dimitri, who goes by Hobbybob, fired 10 liquid flame units he'd built himself at 10 at night on the Friday and Saturday. He burnt through 100 litres of isopropanol a night. On the Saturday afternoon he ran a session called "Flamers of the world Unite!". He opened up one of the units and talked through everything that went wrong while he built it. He'd sourced 16 controllers from a company in China and found out the hard way that the manual said a maximum of 8 seconds of fire time.

• Lasertag ran on all 3 evenings. It was free, with no booking, for ages 7 and up, on gear the organiser had 3D printed himself. There was a queue every night, and you stood in it behind children and people in their 40s in about equal numbers.

• AMSAT-UK, the British Amateur Television Club and the UK Microwave Group ran a joint village. They worked a pass of the International Space Station using the amateur radio voice repeater on board, and I watched from a folding chair. Jeffrey Roe ran a workshop where you build your own ground station on TinyGS, a community-run mesh of receivers that picks up LoRa satellites on cheap modules. You can go from never having thought about it to receiving data from space in an afternoon, for the price of the parts.

• At the Lock Picking Village run by TOOOL and friends, someone hands you a lock and a pick and someone else teaches you. The best lock talk I saw was Etienne Naude's, about a robot he built to make locks more secure. His argument is that master keys are used almost everywhere, including on nearly every suitcase, and that they have structural weaknesses. His machine pushes wires through a 3D printed steel key blank to spoof whatever bitting the lock wants, and the build is open source.

• Hacky Racers raced cheap DIY electric karts on a track in front of Null Sector most of the weekend. It's a registered Motorsport UK club, and people build their karts over the winter. There was also a small pink Lamborghini, which I filmed. It ended up parked at the Brighton Consulate, where Jim Purbrick played a set from it as the sun went down: generative ambient soundscapes under recordings of the last generations of people who'll remember glaciers.

• There was a sandpit with remote-controlled diggers in it.

• There was also a trolley covered in stickers, with a sign on it that said "Please take the art for a walk". So I did.

• At the 2024 edition, which I was also at, somebody left 2 radioactive sources in the swap shop. The swap shop is where you leave things you don't want and take things you do. These were Danish ionisation chambers made by Elektronikcentralen, used to calibrate smoke detectors. They contain Americium-241, the same alpha emitter as a household smoke detector, but a lot more of it. Tryst, who works in civil nuclear and happened to be on site, worked out what they were, sealed them in plastic bags and locked them in the back of his truck. Then he posted an appeal asking if anyone else had taken one, with 3 ways to reach him, including the campsite phone network.

Did you take one of these objects from the #emf2024 swap shop?

If so, please could you get in touch? DM me here, Telegram @tryst_me or call DECT 8797

EDIT: This has now been resolved. The person who brought them to swap shop has confirmed that there were only two sources, and both of them have been accounted for. Thank you for yout help.

• It was resolved within the day, when the person who'd brought them confirmed there had only ever been 2 and both were accounted for. Before that, Tryst couldn't prove there weren't more and said so publicly. Someone pointed out there might be more than 2, and he didn't sleep well. This year he came back with a talk called The Orphan Source Incident, which is worth 30 minutes. Hackaday also wrote up the follow-up.

• An orphan source is radioactive material that has fallen out of the chain of custody meant to account for it. These ones aren't especially dangerous intact, but they're easy to take apart, and an alpha emitter is a lot worse if someone swallows it. Normally they'd go back to the Danish manufacturer for disposal. Post-Brexit regulatory changes mean that route no longer works cleanly, so nobody can straightforwardly take them. He finished the talk by asking the room if anyone had ideas.

• Tryst built the talk so nobody involved gets blamed. Only the manufacturer and the regulators are named. His reasoning is that if you punish the person who left them, the next person in that position won't come forward, and the next sources end up somewhere far worse. If you want people to report problems, don't punish them for it.

• This year the swap shop had a sign up.

• My own talk was on Stage A on the Friday at 17:40. For 22 minutes I talked about how North Korean IT workers try to get hired into your company. It started when I opened a few remote roles and noticed how many of the thousands of applications looked alike. What I found fed into an investigation that contributed to 29 property searches and 5 arrests.

• The official EMF schedule also listed the cside security village. We ran a scavenger hunt for 4 mythical creatures, each standing in for a different client-side attack. Anyone who found all 4 went into a raffle for a retro handheld running Linux. Marc, Jovian and Aarnav did most of the work.

A lot of the schedule was people explaining the parts that didn't work. I believe the security industry could learn from that. When a company finds something embarrassing about itself, the incentive is to say nothing, and everyone else learns the same lesson on their own.

The talk was my excuse to go. Being there was the point.

See you in 2028.