Robotic Labyrinth Update – Long Overdue

4.29.2009- Day 98

Its been over two months since my last post about the Robotic Labyrinth project for Science City.  The project slowed to a more deliberate pace but has not stopped. We are still making progress but acquiring the materials we need have slowed things down quite a bit.

We now have our extruded polystyrene foam insulation board for our maze platform’s sandwich structure and the aerospace adhesives to glue the maze together. Our next big hurdle is getting aluminum to begin fabrication of the maze table.

Platform Actuation

Testing the linear actuators.

Testing the linear actuators.

Richard found these great linear actuators that we are testing. They are providing quick response and an incredible range of motion.

Support Platform for the Maze.

Support Platform for the Maze.

We have a 4′ x 4′ platform constructed from two sheets of 3/4″ plywood. This is planned to support our maze table on top of the structure. We are still waiting for the labyrinth’s base to get out of the sheet metal shop so for now we’re using a spool with electrical cables for weight.

Universal Joint Mounting Plate

Universal Joint Mounting Plate

This view shows our universal joint mounting plate on the underside of the maze support platform.

Temporary Relay Switches.

Temporary Relay Switches.

We are able to move the platform with the joystick. It is temporarily controlled using relay switches.

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A Chipper/Shreader Revealed

I like getting Make Magazines and have a Maker mentality so it’s normal to consider DIY projects. I’ve been wanting a Chipper/Shredder for a while so last year I started wondering what it takes to build one. I started on my usual search of the Internet for inspiration but mostly found sites that warned against doing such a thing.

The best example of a DIY chipper I found is the 5″ Horizontal Wood Chipper by Steve Bedair. It is worth taking a look at this machine. His disclaimer page gives proper warning about risks involved when attempting a project like this.

Chipper shredder

Craftsman Chipper Shredder

I like the motto, “Safety Third”. I don’t advocate carelessness but think it is important not to shy away from a project just because there are some dangerous aspects. I put my search on hold, however, after spending a few dollars on a Craftsman Chipper/Shredder at a garage sale last year. The body of the machine had some areas with fiberglass patching so I expected it would need additional work but overall it looked intact.

Recently, I pulled it out of the garage and plugged it in. Starting with small twigs it chewed up the pieces and spit them out the other side. I tried some larger pieces and was working on a small branch about 1/2″ in diameter. Suddenly the machine’s houseing disintegrated into pieces. The fiberglass patches stayed intact but the brittle plastic couldn’t stand the abuse.

Recently I found this on Twitter by @bkmontgomery
Thinking about building a homemade leaf vacuum/chopper/bagger. Wonder if the motor from a circular saw would work…

I thought I would share some details about how this machine is built. I took it to the CCCKC Underground Lab and began taking it apart.

Chipper shreder with the top shroud broken off.

Chipper shreder with the top shroud broken off.

Removing the shroud exposes the chopping blades inside.

Branch feeder housing.

Branch feeder housing deposits branches on top of the bottom blades.

Shroud removed and blades exposed.

Shroud removed and blades exposed.

Base with top blade removed

Base with top blade removed

Top Blade

Top Blade

The top blade is made from about 3/16 inch steel.

Bottom blade revealed.

Bottom blade revealed.

The bottom blade has more aggresive teeth but like the top it appears to be made from a flat sheet of steel then bent to form the teeth. Notice the extra blade on the top that chips the branches fed into the side chute.

View from the bottom.

View from the bottom.

Model Number Label.

Model Number Label. (click on picture for full image)

The motor size is 10 Amps at 1.5 horsepower.

Craftsman Chipper Shredder Label.

Craftsman Chipper Shredder Label.

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Makers Night Out in Kansas City

OpenCV Study Group

OpenCV Study Group

March 31, 2009 was our first night of combining the OpenCV Study Group with a weekly Maker’s Night Out session in the CCCKC Underground Lab. We changed things up for the OpenCV session with a presentation by Amith about fundamentals of image processing. He uses these techniques every day for medical imaging research.

Amith gave a brief comparison of medical imaging in a 3D environment using voxels where the 2D environment uses pixels to represent images. I’ve started reading the book Non-Photorealistic Rendering where a 3D model is used to represent surface textures of drawing materials in pencil sketches, pen and ink, and painting methods. Voxels are used there to simulate voids in the drawing surface where the art medium is deposited.

Amith spent a few minutes talking about video compression techniques and how a frame is displayed showing the entire image while subsequent frames only show changes from the previous frame, these are called P-Frame and I-Frames. The I-Frame or Intraframe is also called a keyframe and contains the entire image. The P-Frame is a predictive frame that only contains the changed data. A couple of nights earlier I came across a great example about How to Datamosh that plays with combining two video segments when most of the I-Frames are removed.

He also gave an overview of filters used in image processing and touched on a few filtering methods. For our next OpenCV session he would like to give some demonstrations of what various filters provide. As a challenge we are looking into methods of being able to use an image to identify coins and denomonations of coins.

Makers Row

Makers Row

Jestin was showing some of his recent work in OpenCV using color correction and filters to display live video. I had the prototype of a project I’m calling a Refrigerator Art Machine designed to capture artwork using OpenCV.

Others were busy tonight working on various Maker projects and crafts.

More OpenCV Study Group Notes

Meeting: Study Group Notes – 1.22.2009
Meeting: Study Group Notes – 1.8.2009

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