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HDPE Disaster

HDPE Sheet

My most recent HDPE adventure did not turn out well. While I got a nice sized sheet, I managed to slice my finger open and wasn’t sure why, until I investigated more closely…

HDPE, now with glass!

If you can see those shiny pieces, those are pieces of glass. But since I’m personally cutting up all the HDPE scraps and putting them in the oven, where did this glass come from?

Glass, damaged...

Oh yeah, I put it in the oven in a glass baking pan. The HDPE actually tore some layers from the bottom of the pan when I was removing it! The HDPE doesn’t exactly fall out of the pan, and requires some coaxing to come out. I typically pry it out with a screwdriver, then pull it out. (I wear gloves the entire time, as that stuff is HOT!)

Obviously the glass baking pan isn’t ideal for this. I’ve gone back to using the smaller glass loaf pan. I’m hoping the smaller surface area will help prevent this from happening again.

Baked to Hell!

The glass pan is pretty beat anyway, and with pieces missing from the bottom, I guess I’ll just scrap it. (Unless someone wants to melt it down!)

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Maker Faire Milwaukee

Maker Faire Milwaukee

While I’ve been posting a lot lately about plastic and other odd things, pretty much all of my time these days has been filled with planning Maker Faire Milwaukee.

If you’re not familiar with what a Maker Faire is, here’s a quick description from the history page of makerfaire.com

Part science fair, part county fair, and part something entirely new, Maker Faire is an all-ages gathering of tech enthusiasts, crafters, educators, tinkerers, hobbyists, engineers, science clubs, authors, artists, students, and commercial exhibitors. All of these “makers” come to Maker Faire to show what they have made and to share what they have learned.

What I love about Maker Faires (I’ve attended about eight of them in various cities the past few years) is that the people who share their work (or play) are passionate about what they do, and they love sharing it with others. I find this inspiring, and I usually leave excited about what I saw, and eager to learn new skills and make new things.

I’m planning to do a talk about The Power Racing Series, and help out showing off tiny electric vehicles built for under $500, but most of my time will probably be spent working with the folks from Betty Brinn Children’s Museum and Milwaukee Makerspace just making sure everything runs smoothly. (The two organizations are co-hosting the event, and I’m an employee and member of them both, respectively.)

I hope to see you at Maker Faire. If you’ve got kids, it may inspire them, and if you’re a kid at heart, you’ll love it too. (Don’t get me wrong, adults are welcome too!) And, Maker Faire Milwaukee is FREE to attend, thanks to our great sponsors! (And yes, there are still sponsorship opportunities, so get in touch with me if interested!)

If you want a preview of what you’ll see, check out some of the blog posts I’ve been writing.

(Oh, Maker Faire Milwaukee takes place at State Fair Park on September 26th & 27th, 2015, and Harvest Faire is also happening at that time, and also free, so really, there’s something for everyone… Come on down!)

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Raspberry Pi auto login

Linux

Occasionally I post things here because I may need them in the future… this is probably one of those things, which is setting a Raspberry Pi to auto-magically login to the shell (not the desktop) on boot.

Install and configure Raspbian as you normally would, setting it to boot up to the command line, not the desktop.

Boot the Pi and login as the user pi, and then run the following command: 

sudo nano /etc/inittab

Find the following line: 

1:2345:respawn:/sbin/getty --noclear 38400 tty1

and comment it out by adding a # to the front: 

#1:2345:respawn:/sbin/getty --noclear 38400 tty1

Just under it, add this line: 

1:2345:respawn:/bin/login -f pi tty1 </dev/tty1 >/dev/tty1 2>&1

Save the file, quit nano, and reboot.

Obviously this can pose a security risk, just like any other auto-login procedure. If you’re using a Raspberry Pi that is not connected to the network, and doesn’t have a keyboard attached, and is secured in a case, there’s a bit less of a concern.

(Most of this info is from the post Auto Login and Auto Start in Raspberry Pi. Thanks!)

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Milling Recycled HDPE – Workflow

Make

I wanted to document how I did the artwork and toolpaths for the MAKE thing I make on the Shapeoko CNC router at BAMspace recently…

Make

I started with my old MAKE design in Inkscape and set it to the size I wanted. I also placed it on the canvas as if it were on the piece of stock, knowing that the lower left corner would be the home position on the CNC router.

Make

After I saved out my SVG file, I loaded it into MakerCam. Now, you can go to www.makercam.com and use that, or you can load up the SWF, and save it locally to run on your own machine. (Flash is required either way. I guess the source code is also available, but you probably need Adobe’s Flash development tools to do anything with it.)

If you’re using Inkscape, you need to set the prefs to 90ppi instead of 72ppi before you open your SVG file. Oh, make sure you check out the MakerCam tutorial, help, and about pages.

Make

In MakerCam I created two profiles, one to cut the inside pieces, and one to cut the outside of the entire piece.

Make

These setting worked fairly well. I would up the feedrate or the step down on our machine if using 1/2″ HDPE. This job definitely took a while to run…

Make

Once I had the toolpaths all set in MakerCam I exported the G-Code into a single file, and then loaded that file into OpenSCAM to run a simulation. (Looks like OpenSCAM recently rebranded as CAMotics… guess I should grab the latest version!) Running the simulation allows you to see the toolpaths and check how many passes it will take to cut through the material. I guess you could also use math, but sometimes I prefer visualizations…

That’s pretty much my workflow for 2.5D toolpaths; create art in Inkscape, load it into MakerCam and generate G-Code, load G-Code into OpenSCAM (CAMotics) and see how it looks.

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Nuclear Fuel Cell

Nuclear Fuel Cell

While Kathy was working on some top-secret project involving a giant robot I decided to tear apart an old laser printer that was in the junk pile at the shop. Inside I found a wonderfully green drum, which I thought would make a nice “Nuclear Fuel Cell” prop. Of course it needed some vinyl added to it…

Silhouette

I used Inkscape to design my labels. I prefer to use Inkscape to design things, then export a DXF and import that into the Silhouette software. If you design things in the Silhouette software (at least the free version) you can’t export it for use elsewhere.

Silhouette

Oddly enough, the circle part of the radiation symbol got lost. (It’s on the back, so you can’t see it in the photo above.) By the time I noticed it was too late to redo it because I wanted to crank this out in fast.

Anyway, if you stop by Maker Faire Milwaukee on September 26th & 27th, 2015 at State Fair Park, you might just see this Nuclear Fuel Cell in action…