Posted on

Plotting Plotters

Well so, I fell into a very deep rabbit hole. The world of pen plotters… A year in, I finally have some good results. After several prototypes of Gondola plotters (V-plotters) and regular tabletop plotters. I’ve homed in on a set of designs, hardware, electronics, and algorithms to think I can make a small difference in that world. I still need to iterate a little but I’m hoping to release each plotter as a DYI projects in 2020. Maybe I’ll even sell my making them for others. Of course there will be integrations with Mandalagaba because that just makes sense.

Now there are several such plotters one can buy or build for a wide range of prices. And they all have a very shitty software stack. This is where I believe I can make the biggest difference.

As with building houses, it’s enormously relieving to finally see into the real world a model you’ve been immersed in, CADing it for a year.

I’ll skip talking about the long series of challenges I ran into building this. It’s really, really nice to see a long plot finished to perfection knowing that finally, nothing is wrong. I’ve learned a lot along the way.

There’s a bazillion pen plotters on Thingiverse, I’ve used some of them as stepping stones until I was ready to finally make my own top to bottom. As I said, software is where I think I can make the biggest difference. I’m a Raspberry Pi aficionado, and this opens the door to a sophisticated software stack (web servers, HTML canvasses, format conversion, penstroke optimization, live link with Mandalagaba). I found not a single plotter using a Pi, in fact I found very few projects of anything using stepper motors with a Pi. I had to do some serious trail blazing to step a motor reliably.

Here is for example a pen stroke optimization algorithm I developed to speed up plotting.

 

The base, drawing penstrokes as they come. “Empty” travel going from one penstroke to the next without the pen drawing: ~36437 (relative pixels).

The next penstrokes is the closest. Empty travel ~15820, 0.43 compression ratio.

The next penstrokes is the closest, but consider its beginning as well as its end, draw the penstroke reversed if it was the end which was closest. Empty travel ~12467, 0.34 compression ratio.

 

Now for the eye candy 🙂

I could watch this for hours, and I did.

Of course the efficacy of this algorithm depends heavily on the model to be drawn. I found that anything coming from Mandalagaba tends to benefit enormously, especially tessellations. And it makes sense, for every penstroke drawn, the repetitions occur throughout the canvas and they show up in that order even if you drew in a very localized area. The example above comes from the most excellent turtletoy.net.

More to come very soon on the great world of plotters…

Posted on

Wooden Snake

This is unfortunately not an improvement from my last attempt. The design is barely visible due to my poor choice of facing bark. Still, I’m trying to get better at this every year.

Posted on

Done with the Roofers

So far in building, I’ve been happy to contract out roofing to otherwise more capable people with better tools. It’s always notoriously difficult to get contractors to show up, roofers even more. And I get it, no one wants to do their work and so they have even more leverage than most contractors. They don’t care what your building schedule looks like, they only care to have work lined up on their own schedule and will say anything to keep it that way. Their incentive is to keep you waiting so you’re available for them when they have a gap. This year I had it waiting for them and getting strung along, I couldn’t afford it any longer with Winter right around the corner so I went ahead with my usual “screw it, I’ll just do it myself”.

All in all it’s not very difficult but there are a few tricks to pick up, and it is definitely physically hard and fairly dangerous.

I was quoted $2800 for this roof, it ended up costing $1100 and I spent an extra $200 on metal cutting tool I didn’t have, and $250 on climbing gear to be safer and because I want to climb trees for fun. It also “cost” me 2 and a half days of work. I can’t say I’m sad I had to do it myself for the savings and tools I got. The real silver lining though, is that I’ll never have to call a roofer ever again. I now possess the knowledge and the tools. Now that, is a freeing feeling :).

After this, I finally got to proceed with the siding which was long overdue. My dad who is the worst handyman I know (I learned all my swear words watching him with a hammer), came out and helped. I was very apprehensive going in, one of the unspoken worries of homesteading is when people of little manual ability decide they too want to have a homesteading experience and offer their help. He ended up doing really great and helped a lot. Agnes stained a whole bunch of boards, both saved me a lot of time in one day.

I laid shiplap diagonally for strength, we get high winds and this shed has 12′ walls to catch them with. I was ok compromising aesthetics for strength. It turns out it looks really good. We’re very pleased with the result.

I put the roof on right before a big rain, and I sided 1 wall right before a big wind. Right on time, not waiting for the roofers was the right decision, I could have been in trouble if I had: more water ruining the frame, the wind catching in the big sail that is the roof without any structural strength against shearing.

Previously I could hear the building move on little wind gusts, with only 1 wall sided with diagonal boards though, I did not hear a peep during strong gusts. Diagonal is the way :).

I’ll be pushing hard in the next few week ends to close it all up. There is a lot of work left and it really needs to be done before the snow invites itself to Vermont.

 

Posted on

Hard Cider

Rebel without a cause, but with a bin full of apples

Hisse et oh

Using refined cane sugar is not an option

And now we wait