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Dragon of Recursion / Light Show / Post-it Portraits

7 days, 47438 pen strokes :\. Lara’s work and a recurring dragon on this blog :). I sped up the machine to make it 7 days instead of 10, so it’s slightly more inaccurate, but more importantly I failed to anticipate that ink would run out faster. I used to have about 1.5 days between pen swaps, here it’s barely above 1 day. No harm done I got there in time, but I should have thought about it when I adjusted speed.

I lined it up with a big public event and tons of people got to see it.

No sure if there’s anything more to say about lasers & post-it portraits, it was the now usual formula. I’ve enhanced the pipeline some to do auto-face-cropping as it is a step we usually waste lots of time on. Esther & I rehearsed over the week end. She runs the operation during the event.

Some recurring questions I get asked at these events:

“What are the machines for normally?” Nothing, their sole purpose is to drag pens and shine cat lasers.

“Is this your job?” Nope, just a side quest.

“So how does this work?” I try to see what part they’re interested in before I launch into a 3 hour tirade :).

“Did you build this?” yes.

It’s very gratifying to see people stare at your work for a while. You can see the gears turning in their heads. I’ll sit by the big machine sometimes to watch people’s reaction to it. When I swap its pen people will come up and tell me how much they like it. I’m just glad for having the opportunity to do something cool in the world.

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Refining the Formula

I was invited back to the science museum to do something cool with my machines. Any time I do a public event it’s an opportunity to figure out what’s engaging and do better the next time around.

I was maybe a little too motivated and brought several machines, almost my whole apparatus, and deployed them in various modes. 1 PewtyBot, 1 Mirror PewtyBot, 1 PlottyBot & 1 SkecthyBot doing portraits, and 1 PewtyBot people could control with their phones. The laser portraits worked wonders again, but the original PlottyBot drawing post-it portraits worked even better.

People were clearly keen on getting a tangible souvenir from the evening. Having a robot draw their portraits on a Post-it note struck a chord hard. I think what I’ve learned from this event is that while the lasers throw a lot of pazzazz at you, they are more complex machines that most people don’t try to engage with beyond taking in the light show. While a pen based machine is doing the same thing you’d do with your hand so it’s more approachable to be curious about. As usual a small fraction of them were fixated beyond reason on watching the machine at work. There has to be a “drawing automaton obsession” gene present in ~10% of the population.

Unfortunately, I only had one PlottyBot doing the Post-it portraits, and they take much longer than the lasers so I spent much of the evening trying to keep track of a queue of people who wanted one.

I built 2 4’x4′ photoluminescent paper holders so I could deploy this easier. In the past, finding a decent spot on a wall for the rolls and unrolling them was difficult and time consuming. I also have plans for doing random outside events at dusk in random places this Summer, which is why having something deployable was worth the construction effort. I tried it some already at home last Summer and it’s kind of cool to have the lasers go on a warm Summer night.

I had several people ask me if this was AI :), this seems to have become the go-to explanation for anything tech based that can’t be explained easily. Much like Clarke’s law that “Any sufficiently advanced technology is indistinguishable from magic”, only now it’s AI instead of magic. I’d respond that it was just good old organic grain-raised free-range “I”.

As usual, it was very hard to capture the coolness while manning it so I don’t have much visuals to represent what went on. Ultimately it’s just me running 5 machines, a software stack and talking a lot. Suffice it to say people were into it and I’m emboldened to keep trying public events. Fun times!

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Overcoming Inertia

The design of PewtyBot 1.0 left something to be desired: the whole top section (stepper motor, assembly & laser) is moving, and that is a decent amount of mass that needs to be accelerated rapidly many times over.

As I was tuning parameters, it became obvious that I needed to slow things down to avoid inaccuracies from the vibrations of a fast accelerating mass. I found happy parameters which led to several public deployments, but deep inside I knew I wanted to try the mirror approach. Instead of moving the laser, it remains static and only a couple of light mirrors are doing all the moving.

Introducing PewtyBot 1.1!

There’s a funny story in there about losing code, reimplementing, and a core issue I was struggling with being solved without knowing why. As always, a few unforeseen challenges got in the way, but ultimately the math is exactly the same as PewtyBot 1.0 so that was a relief. It’s just the motion code that needs to be adjusted some to deal with mirrors.

And well the results are cool, but somewhat mitigated. Definitely not “rocks your socks off” levels of cool. I can definitely move the laser a lot faster. Although through the exercise, I’ve realized that the “slow” speed of PewtyBot 1.0 may have been in the perfect sweet spot for laser light retention on a photoluminescent medium. And so maybe I got lucky there. Of course I could get a beefier laser that emits more light to compensate for the reduced time it spends on any particular area. I’m pretty convinced though that I want to remain in the “cat laser” realm for risk & safety. And so the other variable I get to play with is mirror quality, and I shouldn’t be surprised that there exist a whole world of mirrors of various specs. I got some very cheap craft type acrylic mirrors at first to test concepts. But you can tell the pointer hits the medium diffused and discolored. And so ultimately I’ll want to spend the money on a few square centimeters of first surface mirrors rated for blue light wavelengths. But first I’d like to convince myself that the mirror approach actually brings something extra to the table.