For Posterity

The first successful prototype of PewtyBot.

Philip from Germany got in touch to tell me about a cool project he had seen that involved photoluminescent paper. He thought maybe PlottyBot could so something with it, and maybe it could, but not fast enough I thought. I knew exactly what I wanted to do with it though, with the PlottyBot software stack, but a different machine. I love that people get in touch to show me cool things. I’ve been working on plotters for years now, and in some sense it felt like I had turned every stone. Out of nowhere Philip got in touch and steered me toward a whole new area of exploration. Of course one can buy glow-in-the-dark paper, of course I can shoot lasers at it, of course all the algorithms I’ve been working on these past years lend themselves to this new endeavor. Well, with some tweaking :).

It was a real struggle to get Trinamic drivers working on a Pi, but I wanted to step up my motor stepping game. Once I figured it out, holy shit do they work! There’s much else to talk about here, but this isn’t the point of this post, I just want to capture the miletone that is shooting lasers super fast at photoluminescent paper. I still haven’t wrapped my mind around what this all means.

PlottyBot Port

I stumbled upon electronically actuated Etch-a-Sketches, and I pretty much had to see if I could port the PlottyBot stack to the toy. It was pretty straightforward. I got the parts from someone else on Thingiverse for a smaller Etch-a-Sketch and the fit isn’t great, but it’s enough of a proof of concept to know I want to make a nice big one, and really the work is all mechanical at this point. How about a web enabled Etch-a-Sketch that can write in your handwriting?

Beefed up Sensoring

A friend bought a couple of Sensirion SEN54s and I helped him get one working, and ended up buying the extra from him. It had been a few years since I researched what sensors were out there that worked well with Raspberry Pis, and were more on the industrial side than the hobbyist side. I was immediately enthused by Sensirion’s documentation, and their sensor looked top notch. My friend did all the homework on reading specs and comparing with others, it was really a no brainer.

With this SEN54 we’ve gained:

  • accurate humidity (the previous sensor was worthless)
  • VOC
  • PM1.0
  • PM2.5
  • PM4.0
  • PM10.0

It’ll be interesting to see the patterns. I’m honestly a little worried about what the particles will reveal seeing as we’re running 2 wood stoves in the house for half of the year. Reassuringly, the first few readings show we’re in the green, but then Nicole opened the stove to let out a bunch of grilled cheese sandwiches and the readings skyrocketed well above WHO guidelines for particles.

But those are only delicious cheese particles finding their way into your nostrils, surely that can’t have and adverse health effect. Jokes aside it’s interesting to see how much of a tail this benign event has. I’ll be really curious to discover more, I really have no idea what I’m looking at yet.

I am very glad to see the Pis become established as industry capable devices. It’s honestly remarkable what I’ve thrown at them over the years while they kept serving their purpose.