Etching Glass Using Vinyl Stencils

29 Apr

I’ve been using my vinyl cutter recently to create custom glass etchings.  Vinyl resists the acids in glass etching cream making it perfect for high resolution stenciling.  The cream I use is can be found here (I picked some up at a Michael’s craft store).  You’ll want to be careful and read the full Material Safety Data Sheet for armour etch.  You can etch most glass but not pyrex (Borosilicate).   The results are pretty neat:

Coaster with an etched crane

Coaster with an etched crane

To start the process, you’ll need to create a vinyl cut and apply it to your glass:

Applying the vinyl negative

Applying the vinyl negative

Now, put on your gloves (seriously) and paint on some etching cream.  I also use an exhaust fan in a nearby window for added safety:

Paint on your etching cream and wait

Paint on your etching cream and wait

After about 5 minutes, I rinse off the etching cream.  The MSDS mentions that baking soda can help neutralize some of the acids; you’ll want to flush everything with lots of water.  Here’s the final result:

Final result of vinyl resisted glass etch

Final result of vinyl resisted glass etch

More photos via flickr: http://flic.kr/s/aHsjz5247h

Zurich Bog’s Carnivorous Plants

8 Jun

Zurich Bog, an advanced sphagnum bog or peatland in upstate New York, was given to the Bergen Swamp Preservation Society for preservation on December 10, 1957 by Lyman Stuart and the Newark School District.  Over 50 years later, the bog supports  a cornucopia of native plant species including carnivorous sundews (Drosera rotundiflora) and purple pitcher plants (Sarracenia purpurea). I had the pleasure of hiking the bog on April 30th, 2011 with environmental scientist Valerie George as a guide and my girlfriend Meaghan Boyle.  Non-carnivorous plants you might find in the bog include: “water willow, highbush blueberry, mountain holly, black huckleberry, small cranberry, and several species of orchids” (Johnson, 234).  I captured the following two images of the bog’s carnivores soon after the last frost in the area and before anything had begun flowering:

Drosera rotundifolia in the Zurich Bog

Drosera rotundifolia in the Zurich Bog

The species of sundew above was “made famous by Charles Darwin’s tireless and hideous experiments upon it” (D’Amato, 136).  It captures insects with its sticky glue-like dew and tentacles that slowly wrap around the prey as it struggles.

Sarracenia purpurea in the Zurich Bog

Sarracenia purpurea in the Zurich Bog

The purple pitcher plant above is one of the American Pitcher Plants which is a different genus than the Tropical Pitcher Plants (Nepenthes).  The collar of the purple pitchers are “covered in bristly, downward-pointing haris.  Insects often cling to and slip from these hairs, which are wet with nectar” (D’Amato, 75).

According to Valerie, early June is the best time to observe the purple pitcher plants in flower.  Definitely check it out if you are near upstate, NY and hike with respect in these fragile peatlands.

Works Cited:

D’Amato, Peter.  The Savage Garden: Cultivating Carnivorous Plants.  Ten Speed Press, 1998.  Print.

Johnson, Charles.  Bogs of the Northeast.  University Press of New England, 1985.  Print.

Pygmy Sundew Propagation by Gemmae

28 Apr

I recently ordered a number of carnivorous plants from Cook’s Carnivorous Plants as well as CP Jungle.  One of those plants was a pygmy sundew, Drosera Scorpioides.  I wasn’t sure what was going on with the top of the plant at first; was it flowering?  It was actually producing gemmae or brood bodies that may be propagated asexually.  These are modified leaves that break free in the wild when struck by rain and they each contain an exact clone of the parent plant.

Here is a 2.5 minute video showing my process for propagating my new Drosera scorpioides from gemmae:

 
This is the plant the same day it was received from Cook’s Carnivorous Plants:

Drosera scorpioides, a pygmy sundew

Drosera scorpioides, a pygmy sundew

I fed my plant a moth 2 days before removing about 5 of the gemmae, 2 of which you see in the video above.  For the morbidly curious, the video of the moth being enveloped by the sundew tentacles is below.  After about 30 seconds the footage is sped up to 2000% although you’ll still probably want to skip forward as there is a lot of footage.  Notice there are a few more gemmae on the plant in this video:

Kinect + Blender 3D Scene Reconstruction

7 Apr

One of my current projects is to find a cheap and accurate way to 3D scan faces for the creation of custom coins and memorabilia;  mostly, I want my face on a 3D printable coin which can then be cast more cheaply in metal.  I had the opportunity to borrow a Microsoft Kinect which has 2 cameras and a structured light infrared laser projector.  One camera captures the infrared laser grid as projected into the room and constructs a depth map in realtime of the entire view.  The other camera captures visible light e.g. normal images and video.  I used the kinect to capture images and depth maps and reconstructed the scene in 3D using blender.  To dump the data, I used libfreenect‘s ‘record’ program, part of the OpenKinect project.

Here’s is a camera panning animation of the result created in blender using a displacement modifier on a heavily subdivided plane:

This is the unedited depth map that I took from the ‘record’ program output:

Kinect depth map produced by libfreenect's record utility

Kinect depth map produced by libfreenect's record utility

I had to scale and move the corresponding image texture to fit the geometry properly.  This is partly due to the slight distance between the cameras.  Here is the slightly altered texture image captured by the kinect:

Kinect image captured using libfreenect's record utility and slightly edited in gimp to align

Kinect image captured using libfreenect's record utility and slightly edited in gimp to align

This is the depth data as determined by blender’s ambient occlusion rendering:

Blender render showing depth via ambient occlusion

Blender render showing depth via ambient occlusion

I will soon compare these results to the free version of DAVID-laserscanner.  I’m currently waiting on the arrival of a very cheap laser line module ($2.50 to be exact) that will be used in conjunction with a high-def camera as input to the DAVID laserscanning software.  Stay tuned.

UPDATE: I’ve attached the .blend file for exploring in blender.  Textures are embedded.  Blender 2.56 Beta or later is recommended.

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The Open Dream Journal Clip

1 Apr

I have wanted to design a simple notebook clip with an LED light for use on a dream journal for quite some time now.  Writing down dreams at night is difficult without a very convenient light source.  Now with access to a MakerBot 3D printer at sprout studios, I’ve released an open dream clip design on thingiverse, an online database of freely available and printable 3D models.  My design uses an LED and CR2032 battery, components commonly available at hackerspaces that would have 3D printers (and radioshack, although the parts are cheaper online through sites like digikey and mouser).

Here is the dream journal clip in action:

Dream Journal Clip with a white LED

Dream Journal Clip with a white LED

The first revision is pretty rough and we had to use tape on it to make it work:

Dream Journal Clip with a red LED

Dream Journal Clip with a red LED

Here is the MakerBot that Jimmie Rodgers kindly tuned and used to print the first test:

MakerBot at Sprout

MakerBot at Sprout

Planned improvements include:

  • using less plastic
  • making a larger hole for seating the LED
  • making a larger and deeper battery slot
  • adding a plastic tab to hold the battery in place (instead of tape)

Download the source files for the open dream clip on thingiverse and keep an eye out for  improvements shortly.

Food in the City and Subirrigation

24 Feb

I was recently invited by Shaunalynn of sprout & co to speak at the Food in the City Spaghetti Dinner about my experience with subirrigated gardening.  Subirrigated gardening is a way of growing plants that conserves water, preserves fertilizer, and simplifies watering.  I regularly consult the Inside Urban Green blog for information on subirrigation which is authored by Bob Hyland, founder of the Center for Urban Greenscaping and the definitive subirrigation guru.  Other topics for the evening included raising chickens, Sam Katz-Christy on his Somerville yogurt co-op, Tai Dinnan from Groundwork Somerville on maple tree tapping and syrup making, and Mike Nagle on window farming in urban areas.  Live illustrations were created by Isaac Bell during the talks which reflected the topics at hand.

I’ve been interested in making my own yogurt for some time now and learned a lot about the process as Sam fielded an array of questions from the crowd.  The co-op operates from the industrial kitchen of the Clarendon Hill Presbyterian Church and sources milk regionally from Crescent Ridge Dairy. Crescent Ridge Dairy delivers in glass containers which helps reduce plastic waste when making yogurt in large batches;  Sam’s simultaneous consideration for the environment and community was inspiring.

Sam Katz-Christy fields questions about yogurt making and running a co-op. Photo by Meaghan Boyle.

Sam Katz-Christy fields questions about yogurt making and running a co-op. Photo by Meaghan Boyle.

My talk reviewed the principles of subirrigation including 2-liter soda bottle designs and larger planter designs based on corrugated drain pipe which are more suitable for growing vegetables.  The planter below was built from a 3-liter bottle and housed a couple of happy basil plants.  Herbs do very well in these 2 and 3 liter designs.

A 3-Liter planter that I built to grow basil. Photo by Meaghan Boyle.

A 3-Liter planter that I built to grow basil. Photo by Meaghan Boyle.

For growing tomatoes and peppers, the corrugated pipe planter designs are the easiest and most reliable to build.  Below is a section of the corrugated and perforated pipe cut to fit in the bottom of the clear container shown to the right of me.  I would use this planter to grow one tomato plant or two pepper plants.  Clear containers allow you to observe water levels without detriment to the plant.

Showing off corrugated and perforated drain pipe for building planters. Photo by Meaghan Boyle.

Showing off corrugated and perforated drain pipe for building planters. Photo by Meaghan Boyle.

There was a great turnout for the talks.  The picture below by Chris Connors shows a small fragment of the assembled crowd;  I really enjoy hanging out after talks at hackerspaces to meet new people with similar interests.

The crowd at Sprout as well as live artwork being projected behind me.  Photo by Chris Connors.

The crowd at Sprout as well as live artwork being projected behind me. Photo by Chris Connors.

I am working on finishing a Make Project page which will include details on fertilizer, pesticide, and other concerns.  For more information on subirrigation I highly recommend the Inside Urban Green Blog as well as the EarthBox Forum.  Now is the time to order and start your tomato seeds for the upcoming season!

If you’d like to stay in touch with sub-irrigators in Somerville, MA and Boston, join the Sub-irrigate Sprout google group.

Hawaiian Sweet Bread with Laser Cut Flour Stamp

10 Feb

I’ve been working on a technique to use flour to stamp breads with laser cut designs and  have finally found a technique that works acceptably well for intricate patterns.  The breads below were made with this Hawaiian Sweet Bread recipe.  Here is the result after baking:

Finished Loaves with Flower of Life Flour Stamps

Finished Loaves with Flower of Life Flour Stamps

The pattern I chose is called the Flower of Life.  It is a six-fold symmetry made with overlapping circles.  Here is a video of the cardboard stamp being cut:

Once you have a cardboard stamp, you can moisten it with water to curve it slightly to fit the loaves.  I did this by using a rubber band placed around the pattern and a can of corn meal.  About 10 minutes before baking, while the oven is preheating, use a spray bottle with water to wet both the slightly curved pattern and the bread.  Shake flour over the wet side of the laser cut cardboard pattern.  Apply the pattern flour side down and press gently.  Here is a picture of the flour coated wet cardboard being applied to the moistened bread.

Flour stamp being applied to a bread

Flour stamp being applied to a bread

If you’re careful, it should look like this before putting it in the oven:

Bread Stamped with Flour Ready for Baking

Bread Stamped with Flour Ready for Baking

I’ve heard that rice flour mixed with normal flour improves the outcome.  You can also create these patterns with an X-acto knife in cardboard to achieve the same effect.  Have fun tagging your loaves of bread!

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