Leafing with the Mogul

Before #1: Your basic 3/8″ plywood

before01

Before #2: My front door, in need of paint, some aesthetic happiness, a fixed doorhandle, and summer. My desire to add a little decoration to the door is, in part, what led me to the Makerspace. I had an idea for panels to go on either side of the door, but no equipment for making what was in my head. When I saw that the Makerspace had cnc routers…

before02

 

IN THE MIDDLE

I took photos of leaves from the oak tree in our yard:

leaf photo

I traced the leaves in Illustrator, and — by looking at the structure of the tree — made my initial design. I exported the file into svg (with hints from Shane), and Ed helped me use Cambam to convert the svg file into the gcode that the Mogul desires.

Screen Shot 2015-12-01 at 5.33.10 PM

After generating the gcode, we cut the first panel. For me, watching the cutting was like Christmas: exciting — while for Ed, stepping me through the process, this must have been like a long slooooooooow Christmas, watching the design appear through the three passes the router bit made to cut each (complicated) path. (In truth, Ed’s patience and help were the real Christmas present for me.)

first cut

This panel was an experiment for me, to learn about how thin and delicate the connecting pieces could be in such cutting. And I learned: what you cannot see in the picture above is how two of the leaves broke off quickly.

In the next Illustrator file I made (which I then cut on the Mogul with Steve Pilon’s also very generous and patient help), the leaves overlap and made their stems thicker. You might be able to see this in the final picture below, which shows the panels painted and mounted. Merry Christmas!

 

THE END

thepanels

Chocolate Printer Cooling System Test

This week I attempted the first test of the chocolate printer cooling system.  The cooling system is intended to solidify the chocolate just after it leaves the extruder nozzle so that by the time the next layer is started it will have a solid layer to sit on.  The cooling system consists of a centrifugal blower with a brushless DC motor blowing room air into a styrofoam cooler containing a block of dry ice.  The air passes over the dry ice and gets chilled as the dry ice sublimates directly into very cold CO2 gas.  The chilled air and CO2 mixture exit the box through a port with a hose that will ultimately blow the cold air on the chocolate.  At least, that’s how it is supposed to work.  It blows air at -12C as measured via a thermocouple, but unfortunately, the air exit port ices up in about 2 minutes and blocks the air flow.

There are many possible solutions.  I can add a heater to the exit port to prevent formation of ice, or dry the air going into the box using a dessicant cannister or maybe just use water ice instead of dry ice if the higher temperature will still cool the chocolate adequately.   Maybe using an old miniature freezer with an air hose coiled inside would do the job.  It would be really interesting if I could use the waste heat from a freezer to keep the chocolate liquified and flowing.  Back to the drawing board!

ATSAMD21J Test

Recently Arduino came out with the Arduino Zero. This is a neat 48MHz ARM Cortex M0 processor on a PCB with the same pin outs as an Arduino UNO. Existing 3rd party UNO libraries are a little hit and miss because some access the underlying hardware registers of the UNO. The Zero hardware registers are completely different from UNO. Still, the basic 1st party Arduino libraries work fine and I’m sure those 3rd party libraries that were twiddling the UNO hardware registers directly will start to support the Zero over time.

Anway, my curiosity was peaked by the ARM processor for the Zero the Atmel ATSAMD21G18. It turns out that the processor has alternative packages with higher pin counts. Same silicon, just more pins. So I gave the ATSAMD21J18 a try. In order to be able to use extra pins with digitalWrite, I had to add a small amount of code to a file called variant.cpp, but once done, I had a Zero with a nice chunk of extra I/O capability.

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Refreshing the Singing Pumpkin Display

I’m getting my original singing pumpkin display ready for BVNA’s Pumpkin Pavilion and Halloween. The original display was pure prototype electronics consisting a bunch of stuff from Adafruit: an UNO, a Wave Shield, a PWM/Servo driver, and servos. There was a footprint challenged custom PCB for a TDA7297 and some junk bin DC-DC convertors.

OldController

It didn’t look pretty, but it did the job for years. However, the new fully integrated prototype controller looks a lot snazzier.

NewController

There are still more design changes to come for this board, but it was really nice to see it perform as intended in my full display.