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Clem Taylor
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330 followers
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Clem Taylor's posts

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Celebrate the 4th of July by taping out a PCB design.

I'm playing around with discrete LED displays as a part of my upcoming bluetooth low energy project.

The top board is a 48x11 0402 LED array with a 1.6mm pixel pitch. The bottom board is a 32x11 RGB LED array with a 2.4mm pixel pitch.

Hand assembling this beast is going to be a bit of a challenge, far to many components on the top side and 0.5mm chip scale BGAs on the bottom.
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2014-07-04
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I finally got back to working on my printer controller project. This morning I sent off a respin of my 5 axis AMIS-30543 stepper driver board. My initial controller design was monolithic, with everything on one board, but now I'm leaning towards a somewhat more modular design.

The On Semiconductor AMIS-30543 is a impressive stepper driver chip. It has a programmable peak current of 3A per phase and up to 1/128 microstepping. Combining this with a STM32F4 based controller board along with 400 step/revolution steppers should result in some nice smooth motion. The extra resolution doesn't buy you much, but the smoothness of the motion directly translates to print quality.
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2013-06-18
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Normally I'd rather print something I designed then just printing stuff from thingiverse. It is far more fun to be a producer then a consumer, but here are a few thingiverse prints I did recently.

The snowflake tealight (http://www.thingiverse.com/thing:38418) gave me some troubles slicing, skeinforge (via cura) made some really odd fill decisions, but it at least it wasn't the epic fail I got when I tried a git build of slic3r.

The gyroscopic snowflake (http://www.thingiverse.com/thing:36922) showed that I still haven't fixed the problem with inadequate tension in the short belts on my ultimaker (I replaced the long belts, but ordered the wrong part for the short belts). I printed this with 100% infill and it is nice and heavy and the outer flakes spin nicely, the pins on the tiny flake where a bit crunchy.

I printed these in printbl.com sapphire PLA with 0.1mm layers.
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Printing koch snowflakes has been popular lately, so here is my take on a koch snowflake vase. This was generated in python with liberal use of the erosion and dilation operators.

printbl.com sapphire PLA, 0.5mm walls, 0.1mm continuous-z layers, 199mm tall

I made a video, but it came out a bit over exposed and the subject isn't the best choice for a timelapse, but I've already killed the bits:
http://youtu.be/oW53hm99INM
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I was wondering if anyone knows of some software (or an algorithm) for warping/interpolating 2D polygons? I've become a big fan of printing gcode generated by a python script without having to torture a pile of poor helpless triangles. I'm working on a print whose source shapes aren't completely continuous, so I want to be able to interpolate some intermediate layers in a visually appealing way. This is similar to a loft operation in CAD, but the key is that it 'looks good', whatever that means.

The first algorithm I tried would find the centroid of the target polygon and sweep a ray from the centroid to points on the target polygon and find the corresponding point in the source polygon then interpolate along line that connects the points. This somewhat worked on simple prints, but doesn't work with what I'm looking to print now (think fractals).

I need a smarter method of picking corresponding points and something better then a simple linear interpolation of the corresponding points. I suspect I need something that interpolates linearly in area, so one polyline will grow/shrink into the other more organically. Any ideas? 

For reference, I attached some images of my earlier attempts at generated gcode.
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I really like printing thin walls with printbl.com sapphire PLA filament.

This is another 0.1mm continuous-z with 0.55mm thick walls. This was generated with ample use of erosion and dilation operations, while changing both the scale and the distance between the inner and outer points.
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I created a new test object based on reuleaux triangles (http://mathworld.wolfram.com/ReuleauxTriangle.html). The neat thing is if you look at the shape from above the rounded triangle sweeps out a rounded square. Thin transparent PLA looks so cool...
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Here is another vase, printed in printbl sapphire. This print has a weird artifact in the opalescence. I'd imagine I'm printing too hot, but I wonder if there is some other factor. Any ideas?

I'm working on improving the loop scar, I tried changing the loop change point selector for this vase and I managed to make the problem even worse.
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Thanks to the awesomeness of +Dave Durant, I'm printing again!

So I printed some python vases in printbl ruby PLA. Still having troubles with scars where the perimeters intersect, even with continuous-z layers. Unfortunately the semi-transparent PLA really help to show off the scar.

[0.1mm layers, 3 perimeters, continuous-z]
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Today Mr. Postman delivered a box from Digikey, a box from Mouser and a envelop from OshPark. Talk about just in time delivery.

I forgot to order some solder paste, so I'm going to have to solder this one by hand instead of trying my luck at toaster oven reflow.

I noticed a few problem, I didn't leave nearly enough room for the head of a M3 sockethead. When I was ordering the parts I discovered that I used the same stepper motor connector as my A4988 board, which is only rated for 3A/pin. The silk for the orientation of the LEDs is useless. The test point pads are a bit on the tiny side. Well see what happens when I start populating them.
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