Seb Lee-Delisle


Margate games: locating bullets with sound

I’ve been working on a system that uses microphones to locate where a bullet has hit the wall, so that I can make a digital firing range using lasers and Nerf guns. Since I posted last, I’ve been thinking more about the history of arcades, first with traditional manned side-shows, and then in the 80s with the advent of computer game arcades.

I’m thinking that I could join all of these up to the present day – I’m planning on making a shooting game with 80s style laser projected asteroids that break apart when you hit them. I’m also thinking that a laser coconut shy is a ridiculously good idea that I can’t resist building.

I know I promised that I would explain my alternative bullet locating system that uses infrared lasers, but I’m holding off on that. In the last post I explained how I’m using piezo microphones to locate where the hit occurred. It’s a fragile system, and I honestly never expected it to work, but to my astonishment I’ve been getting some good results. Check out this video:

I’m going to keep the infrared laser solution as a plan B, but for now I’m optimistic about this sonic detection system.

This post first published on the Margate Games blog February 2014

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Margate games: Digital shooting gallery R&D

I can’t believe it’s already been two weeks since my first Margate visit and since then there’s been a burst of technical R&D. I’ve decided to recreate the magic of an old fashioned side show, with additional computers and lasers.

I was initially inspired by the Das Blinken Blonken project on Instructables. It’s a hand made electronic ball throwing game where the target has sensors, lights and a scoring system. How fun to throw real things at digital things?


The amazing Blinken Bonken game by Instructable member zippy314

It got me thinking about coconut shies and the knock-down-cans game (known as chamboule-tout in France and Dosenwerfen in Germany). It’d be pretty fun to make a coconut shy where you have real balls, but the coconuts are projected with a laser. But then I heard that there was a history of shooting galleries in Margate, and that led me on the path of creating my own digital shooting game, with physical bullets and laser projected moving targets.

Winchester Rifle Range on Margate seafront

My first decision – what type of gun? I have strong memories of excitedly getting my hands on a heavy air rifle at a sideshow as a kid, so my immediate thought was a BB gun. I immediately went and bought an Airsoft gun – it fires 6mm BBs and are supposedly safe to fire at humans, but are just scary enough to be exciting. As a confirmed pacifist it seems strange to be excited about guns, and even stranger to remember how much I loved playing with cap guns growing up.

OK, so I’ve got the idea, but how do I build it? The main problem that I have is trying to detect where a bullet has hit the wall. My friend Jason Hotchkiss has built a ping-pong table that plays music notes depending on where the ball hits. And his system uses microphones attached to the table, that detect the sound the ball makes. It then calculates the tiny time differences the sound takes to reach each microphone, and triangulates the sound back to the source.

Although it’s not triangulation – it’s multilateration because you don’t know the actual time the sound took to reach the sensors, but only the difference between the times that the sound reaches each microphone. It’s an incredibly complex maths problem – I dare you to have a look at the formula on the wikipedia page. Jason had already solved this problem (with what I know now to be an incredibly clever and fast estimation system), but I arrogantly thought that I could improve on his solution. And promptly headed down into the worst maths rabbit hole you can imagine.

You’ll be pleased to hear that I’ve pretty much come out of it now – (I’ll be sharing the technical details in detail on my own blog once I finish the project). Here’s a short and very early test of the system.

In my next post I’ll be talking about the other solution I’ve been working on that uses an infra-red laser light plane.

This post first published on the Margate Games blog February 2014

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Margate Games residency – revisiting Margate

It was my first visit to Margate yesterday since I was a kid. I walked around and got a feel for the town, and was lucky enough to get a tour of the dilapidated theme park, Dreamland. There are creepers and weeds everywhere – a stark reminder that nature takes over astonishingly quickly when left to its own devices.

As I looked through old photos of the pristine Dreamland from the 40s, I was struck by how gorgeous it was – clean and classy, and very very fashionable. There were perfect little working steam trains, clean white 30s style buildings – everything was shiny. When I visited in the 80s as a kid there was a certain energy and excitement but it certainly wasn’t glamorous, and there was a distinct feeling that this place was past its prime.

Margate clearly has its problems and is rough around the edges. But it’s heartening to see new shiny bits emerging; a completely modernised and refurbished hotel, a proper coffee shop that does a great flat white (pretentious I know but I’d be more than useless without a decent coffee πŸ™‚ ), a bar that serves chocolate, fancy restaurants, including a trendy pizza house all set to attract the local hipster community, and of course the Turner gallery.

It’s nice to see some of the local architecture live up to its original promise; classic Victorian seaside architecture, but somehow more delicate than Brighton (my home town).

It seems that the Geek Festival – and also the work of the game making artists – can work to bring a bit of sparkle back to this historic town. I’m going to be thinking about how I can recreate the joy and excitement of the classic fairground sideshow, using computer technology, sensors, and most likely lasers. Because what’s more sparkly than a laser? πŸ™‚ More of that in my next post.

This post first published on the Margate Games blog January 2014

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Margate Games residency kicks off

2014 is off to a great start and my first project is an artist’s residency in Margate in the run up to the Geek Festival.

I’ll be working on it over the coming weeks and writing up my progress on the Margate Games blog.

I was considering reviving the PixelPhones project but now I’m wondering about something a little bit new. I’ll keep you informed of my progress. πŸ™‚

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Review of 2013

Review of 2013

As the new year starts I like to reflect on the past year, and it’s become quite the annual tradition. Clearly this is quite a self indulgent activity, and I do it more as a reminder to myself than anything else. That said, I’ve really enjoyed reading my friends’ yearly reviews, Remy, Simon, Laura, and Val. So maybe you’ll enjoy this too? Who knows? I can’t promise anything though πŸ™‚



The project that dominated 2013 was undoubtably PixelPyros. After the successful launch of the project in 2012 at the Brighton Digital Festival, the Arts Council suggested that I take the show on tour. In January I started making plans.

It’s hard to describe how large an undertaking this was, so I’ll probably go into it in some separate blog posts. But suffice it to say it monopolised my time for most of the year. The sheer effort of will required to make a project like this materialise out of nothing cannot be underestimated. Finding venues, negotiating with suppliers, applying for funding, health and safety reports, event insurance, and that’s before we even start looking at the technical implications, R & D and coding!

PixelPyros crew Huddersfield
The PixelPyros crew in Huddersfield

Thankfully I had some pretty special people helping, including production manager Becky Stevens, programmer Paul Hayes and designer Val Head, not to mention my friends at laser specialists LM – I couldn’t have done it without them.

It was a massive project, and a big challenge, and at the end of it I’m left with a feeling of elation. The 5 dates nationwide attracted crowds of tens of thousands of people. Artistically and technically I couldn’t be happier, and I loved working with the crew (and the lasers, but more of that below).


The laser and projector set up for PixelPyros

Yes, lasers require their own heading. I spent a lot of time in 2013 playing with lasers. I bought a small one for practicing with in the studio, and on tour we used really powerful ones. It was quite the challenge to get the lasers working in sync with the projectors.

I used the open Etherdream hardware and programmed it with Memo Akten’s openFrameworks addons. (More info on my laser blog posts) I added a lot of new code that I’ll be continuing to work on this year with an aim to release for public consumption.

But on the whole it was just a delight to work with lasers. It’s such a different paradigm from pixels, and the intensity and colours are spectacular. Expect to see more lasers from me in the future.


8436763912_71085c3030_oPhoto by Geri Coady

I spoke at fewer conferences this year than previous ones, mostly because I’ve been concentrating on my projects, and speaking can be quite a distraction, much as I love it.

I gave keynote speeches at FOWD London, Web Expo in Surrey, and From the Front in Bologna.

The speaking highlight for me was probably at New Adventures back in January. It was the last one of three and I’d attended all of the others. Simon and his team put so much love into this conference and this is reflected by the warmth of the audience. It was probably the best feedback I’ve ever had from a conference. And I don’t think it was just because I gave away a Commodore 64.


Spoken Nerd
Glow stick motion detection fun at the Festival of the Spoken Nerd

In April I was offered the guest spot at the Festival of the Spoken Nerd‘s London gigs. It’s a great show and Helen, Steve and Matt were so welcoming – I really enjoyed it. I pretty much just did what I do at conferences (and I always overran – sorry guys!) but it was a real learning experience to present creative programming to a new audience in a different environment. I really hope I get the chance to work with them again, and it’s also given me some ideas for more performance based projects in the future.

Creative Coding Podcast

There was a burst of activity between February and April where my co-host Iain Lobb and I produced a 30 minute podcast live every week. We got some great guests and I liked the new shorter format, but it was still a bit stressful grappling with the various bits of slightly flaky technology to pull it together.

We’ve made the decision to put it on hiaitus for a while, but I’m sure we could be persuaded to bring it back. Do you miss it? Let us know!

Art projects

Lunar Trails print
One off Lunar Trails prints, hopefully going on sale in 2014

Apart from PixelPyros, Lunar Trails also had an outing in Brussels in November at the gorgeous arts venue BOZAR. It’ll be travelling more in 2014, more information on that coming soon.

I also spent a large part of 2013 working on one-off prints, made using a plotter from the 80s. Putting them up for sale has long been on my list of things to sort out – hopefully this year!

My other big project PixelPhones was on the back burner a little, although I expect to revive that in the coming months too.


Photo stolen from Microsoft

In June I was amazed and honoured to win 3 Microsoft Critter awards! Developer of the year, Voice of the year and Web Personality of the year. Truly astonishing.


In March, there was a profile of me in the Make blog, and in December Leila Johnson interviewed me for Hack Circus.

I was also on Canadian national radio – CBC’s Spark program talking about creative coding with Nora Young.

I was a guest on Stacey’s Bitchcast and Happy Monday with Sarah and Josh, as well as loads of radio interviews during the PixelPyros tour.

US visa

It’s been a great year, but it’s not all good news. You may remember that in 2012 I had a bit of trouble with US immigration, and now I can no longer enter the country on an ESTA visa waiver. And when I applied for a visa to visit for the Eyeo festival it was refused! I’m not sure how to fix this one, but I’ll be finding a good lawyer to try to figure it out, maybe next year. Full story on the podcast.


I set up a brand new workshop this year all about making games in JavaScript and I love teaching it! I haven’t had as much time for running workshops as I usually would, but I’ve taken my CreativeJS training to the BBC, Lego and PA Consulting.

My friend and regular collaborator Val Head has taken on teaching my CreativeJS for designers workshop in the USA (and possibly even in the UK this year!).

And expect more UK courses from me this Spring. Sign up to the mailing list if you want to be the first to hear about new workshops.

The site has had another brilliant year with nearly half a million visitors, and there’s a fantastic team of writers covering all the latest and funnest JavaScript projects and tutorials.

What’s next?

2014 is already shaping up well, net magazine are running a big feature about me and my work in the March edition, I’ve got the GEEK festival‘s residency for game-making artists running until the end of February, more CreativeJS workshops, another laser based project in the middle of March, and I’ve been invited to install Lunar Trails in a gallery in France throughout April and May.

Speaking of Lunar Trails, the engineer that built the hanging plotter with me, Paul Strotten, is currently designing and building a delta 3D printer with a view to selling it. It looks absolutely amazing – his stuff is always just really solidly made. So I expect to be playing with 3D printers this year.


So to summarise, I’ve worked very hard in 2013 and it’s been rewarding. The only things I’d like to change are to be able to put more time into my code to make it more reusable and contribute better to open source projects. But on the whole, it’s been great – let’s hope things continue this well in the future.

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Lunar Trails comes to Brussels

Right in the middle of the PixelPyros tour, I’m taking a minor detour to Belgium where I’ll be installing Lunar Trails at the Bozar Night 2013.

There’ll be several other digital installations and performances, check it out if you’re in the area.

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PixelPyros – call for sponsors


In the final run up to the first date at Nottingham GameCity, it’s about time I make one more push for sponsors. It’s a chance to have your name associated with this massive installation that’s travelling around the country. And we’re already getting some sniffing around from the TV stations, so we’re hoping it’ll get lots of profile.

We have platinum and gold levels for the corporations, but if you’re not Microsoft or Google you can still help – we now have micro-sponsor slots starting at Β£100.

Platinum : Entire tour Β£5,000, one night Β£1,000
Gold : Entire tour Β£3,000, one night Β£800
Micro sponsor : Β£100 per night or Β£300 for the whole tour

Not only do you get your logo projected on the screen in-between shows, but you’re also helping the event to happen. Your company can truly be a supporter of this very cool arts project (even if I say so myself πŸ™‚ )

There are limited spots so please mail me [email protected] if you’re interested in one of these. Thanks!

[UPDATE] of course I forgot to mention the most important part! We’re expecting at least 30,000 people to see the show across the tour. We’ve already got a couple of sponsors confirmed so if you’re interested, let me know soon!

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I need your help – November PixelPyros dates available

We’ve just heard that one of the PixelPyros tour locations is having trouble with its funding so may have to cancel, which could leave us with a gap in our schedule for November.


So I’m asking for help – if you know any event, council or company that might want a digital interactive fireworks display with lasers please tell them about us! We’re thinking that there must be a few organisations out there that might like something a bit special for Guy Fawkes night this year.

It’s part of the tour so it benefits from hugely discounted equipment costs – it’s probably half the price that it would normally be, ie roughly the same price as a decent real-life fireworks display (and much more pet-friendly and safe than traditional fireworks).

So feel free to put any potential new locations in touch with me at [email protected] or point them at Thanks!

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PixelPyros development – working with lasers part 2

In the first part of this series, we looked at the basics of how scanning lasers work, so now we’ll cover the equipment that you need and how it all connects together.

lasersPhoto: FFP Laser systems

Reminder : lasers are dangerous and you can seriously damage your eyes or even go blind. If you’re interested in working with lasers, please seek advice and supervision from qualified experts, and always wear eye protection.

25pincableThe ILDA laser interface uses standard 25 pin D-connectors.

First thing up on the equipment list: a hardware interface for the laser. The standard laser interface is called ILDA (named after the International Laser Display Association), and it’s an analogue format that uses standard 25 pin D-connectors, like parallel printers from the past. It’s a well established standard and most modern scanning lasers support it.

So we need something that can provide an ILDA connection and most ‘laserists’ (terrible term huh?) use a hardware/software combination like Pangolin to produce laser shows with pre-set patterns. These systems are pricey, closed-source and totally proprietary.

Thankfully there is an open alternative – a hardware ILDA convertor called Ether Dream. You send data to it over a standard ethernet network, and the Ether Dream converts it into the analogue ILDA signal. (This type of laser interface converts digital into analogue, so it’s referred to as a DAC – Digital to Analogue Converter.)

And thanks to the openFrameworks addon that wraps the Ether Dream SDK it’s easy to get started with it. (Thanks Memo!).

SONY DSCThe open-hardware laser controller – the Ether Dream

I’ll show you how to work with openFrameworks and ofxEtherdream in the next post, but before that, we’re gonna need a laser. For the PixelPyros tour itself LM Productions will be providing us with a crazy high power 11W PIKO laser worth around €30,000. It can handle 80,000 points per second (PPS) and it’s a white laser so I’ll have full RGB control.

pikolaserThe powerful PIKO laser even has a fancy touch-screen controller!

For the R&D part of the PixelPyros project, I need a laser of my own in the studio to experiment with – the 11W laser could easily burn a hole in the wall so it would be a bit over the top! I asked LM for advice, and they recommended the Laserworld CS-1000RGB SE with upgraded galvos capable of 50,000 PPS, priced at around Β£1,000.

The LaserWorld CS-1000RGB SE – a white laser capable of 50KPPS

At 1W, it’s 11 times less powerful than the PIKO laser, but about 2,000 times brighter than an ordinary laser pointer, and still too bright to work with in a small space. I thought that all white lasers had granular control over each colour channel, so I was disappointed to find out that each of the 3 colours were either just on or off. Which meant I couldn’t reduce the brightness – if I want a laser with attenuation, i.e. granular control, I need to get a better laser. (Naturally the expensive PIKO laser is fully adjustable).

In the meantime all I could do is get some tinted acrylic to make the laser less blindingly bright, which helps my eyes!

Next up – the results of my experiments with the laser and the practicalities of getting good clear laser lines and dots.

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PixelPyros development – working with lasers part 1

Photo : Dave Wilson

Over the next few weeks I’ll be working hard on new features of PixelPyros, and I thought it’d be fun to share what I’ve learned. I’m going to start with lasers. Because, well, because lasers.

First, a quick word of warning: Lasers are dangerous and you can seriously damage your eyes or even go blind. If you’re interested in working with lasers, please make sure you seek advice and supervision from qualified experts, and always wear eye protection.

Photo : Rachel Richardson-Castro

One of the few things that humans and cats have in common is that we love lasers, so I’ve felt compelled to add lasers to PixelPyros for a while. Modern projectors are pretty bright, but they can’t get anywhere near as bright as real fireworks. Lasers on the other hand can make super bright points of light – so bright that they look like they are emitting light rather than just reflecting it!

My thinking was that I could use lasers to pick out the bright points in the fireworks, and still use the projectors for the detail. I’m not sure exactly how this will look. I just know that I want really beautiful super bright points of laser light. πŸ™‚

To get started I needed to find people who owned some big lasers, and I was put in touch with LM Productions in Eastbourne. They’ve been experts in laser stuff since the 80s and we got on like a house on fire. Thankfully they’re excited about the project and they’ve come on board as our production company – they’ll be be providing not just lasers, but also the massive Christie projectors and sound system.

Let’s rewind a little and take a quick look at how lasers are controlled. Anyone who’s ever used a laser pointer knows that you can point it at the wall to make a little point of light, and if you move it around quick enough, the persistence of vision effect kicks in and it’ll appear to leave a trail as it moves.

The tiny mirrors used to move the laser. Photo: Mersen

A scanning laser can be moved around electronically to make shapes and patterns. Well, actually, the laser itself doesn’t move at all – it’s reflected off two mirrors. Each mirror is rotated on a single axis – one controls the horizontal position and the other controls the vertical position of the laser.

Slide 1
How the mirrors move the laser, in a very confusing diagram I stole off the internet

Each mirror is attached to a galvanometer, or galvo, which controls its rotation. Galvos use electro-magnets to convert electrical energy into movement – they’re also used on the needles on old-fashioned VU meters. They can be incredibly fast and accurate, cheaper units can move the laser to 30,000 points per second, professional ones can handle 80,000.

VU meters use a galvanometer to move the needle. Photo by Dafydd Thomas

To make distinct shapes, we turn the laser off, move to the start point, turn it on, then move it around all the points in the shape, then switch it off again. Do this again for as many shapes as you want to project. Obviously the fewer points there are the faster your laser moves and this makes the image less flickery.

You can get lasers in most colours, and also ‘white lasers’ – units with integrated red green and blue lasers that can make any colour.

In the next part I’ll talk about the hardware you need, and how to hook everything up and communicate with the laser controller directly.

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