Hand-crafted Charlie-Plexed Tile

This 5×6 LED tile is a key component in a secret project that I’m developing (in secret) with some other folks (whose names shall remain a secret).

Why be so public about something so secret? Because this tile uses a layout technique that lets you build charlie-plexed LED arrays quickly and cheaply — and that’s something worth sharing.

You need to flip the tile over in order to see what’s special about it. Here’s a quick list of features that make the assembly what it is:

  • The back of the tile has six “column” conductors and six “row” conductors.
  • These column and row conductors are connected along the diagonal of the row/column array.  At all other points in the matrix, the row and column conductors are isolated via a layer of masking tape.
  • LEDs above the diagonal have their cathode connected to the conductive row immediately above the LED.  LEDs on or below the diagonal have their cathode connected to the conductive row immediately below the LED.
  • All LEDs have their anode connected to the column that is to their immediate left.

The resulting circuit allows you to individually address any of the thirty LEDs in this 5×6 matrix using only six lines from a micro-controller. Continue reading “Hand-crafted Charlie-Plexed Tile”

Modified MendelMax RepRap Build starting Wednesday

Did you take Peejay’s Intro to Programming with Arduino class? You may have learned that Arduino’s are great for controlling 3D printers such as a RepRap.

Well, hot on the heels of our last RepRap MendelMax Build, I’ve been able to redesign the MendelMax to be a rigid rectangle… the upshot is the build volume is increased (especially in Z) without the footprint increasing. The build volume of this baby is 265x233x190 mm (or ~10″x9″x7.5″). The build assembly goes much faster, too.

Come on by Hive76 starting this Wednesday night to see or help put together another one. If you’ve been wondering about our upcoming 3D Printer Build and Operation Workshop with NextFab Studio, this is a great way to see what the fuss is all about.

Here’s a video of this box design Modified MendelMax printer on it’s first print. It’s been chugging along for a solid few days now, no problems so far. It’s printing so well, it’s time to build another one. Come join us!

Stanford U Machine Learning Study Group

Standford University is at it again with another round of free (as in beer) courses! This time they’re joined by the likes of Princeton, Penn, and the University of Michigan!

Why should you care? Well, Hive76 is forming a study group to help individuals tackle this incredible and challenging opportunity to be found within Standford’s Machine Learning course, of course! Our first meeting will be held tomorrow night during Open House Hours (7-11 PM)! If you are interested in taking this course, please take the time to register with Stanford at the link provided here.

As a place to get started, Mike S. of the Noisebridge hackerspace in San Francisco, has compiled an excellent list of resources for the study group that they have going on the left coast. Do consider joining their ML-specific mailing list!

Folks considering this course should be familiar with programming concepts and linear algebra, for sure! Recommended linear algebra lectures can be found here, and for your open source alternative to MATLAB, check out GNU’s Octave.

See you tomorrow!

Feb 22nd: Meet the Developers of Apostrophe Now!

Apostrophe Now!based out of Philadelphia and developed by P’unk Ave — is “a content management system designed for maximum flexibility with a minimal learning curve. The interface is ergonomic, all content-editing is performed in-context.”

Do you have or are you building a website, but you are looking for alternatives to WordPress, Django and other CMS engines? Apostrophe may be right for you!

Come meet Geoff DiMasi and Tom Boutell, two of the lead developers, and find out all the nitty gritty about Apostrophe. They’ll give an overview of the system, design goals, and features, and they’ll also dive into the code to show us how it’s all put together. Geoff and Tom will also talk about other things Philadelphia (the founding of P’unk Ave, the founding of Indy Hall, and the founding of Ignite Philly).

You won’t find this info on Youtube or Vimeo. Come on down to your favorite hackerspace to learn all about Apostrophe and an awesome Philadelphia success story.

Hive76
Wednesday, February 22nd, 7:30 pm
915 Spring Garden, Suite 519

Last Call: Introduction to 3D Rendering with Blender

Rendered My Little Pwnies in Blender.

Last Call for tickets to this class this weekend.

January 28th, 1-6 pm @ Hive76

If you’ve been waiting to get your ticket, now’s the time to do it!

Download or create a 3D model of your choice and the free and open source Blender (v2.61 or later, http://www.blender.org/) and I’ll take you through the process of texturing, lighting, rendering, compositing, and post-processing to make a photo-realistic 3D render.

You’ll learn the ins and outs of the interface in Blender, a professional strength, free and open source program for 3D rendering, animation, modeling, texturing, compositing, and post processing.

For all the details, click here to see the previous post…

Instrument DIY

DIY Scale (and some other fine instruments)

Ok, you probably can’t make the baby grand in this picture, and even the metronome is likely to be a serious DIY challenge — but you can definitely make a pretty accurate DIY scale, and you can do it cheaply and easily.

I needed an accurate scale for a science project and knocked this baby together (based on this design) using found parts.  I was able to easily measure to centi-gram precision and with a little care, a scale like this could be tuned to measure to milligram precision.

Precision (the ability to discriminate between differences in mass) is largely a matter of careful construction — accuracy (the ability to weigh to an agreed upon standard) is another matter altogether,  and it basically hinges on having an accurate reference.  Fortunately, a great institution, born of Philly — the U.S. Mint — was wise enough to make Nickels and Pennies in rather convenient dimensions.  It turns out that nickels are 5.000 grams and pennies are 2.500 grams — so you not only have sub-milligram accurate references of convenient size — you also have an easy way to cross-check your scale by using nickels to weigh pennies and vice-versa.

Details of DIY Scale

The zoomed in photo shows most of the essential elements of construction.  Basically, I used a threaded 10-24 rod for the balance (10-32 would have been a better choice).  I used a wall-board razor as my knife-edge pivot point.  Two angle-brackets served as a hard, flat surface for the knife edge.  A nickel with a hole in it and some thread served as a reference weight (I wound up with a whole array of perforated nickels and pennies). A wall-board T-square served to measure the distance from the pivot to the reference weight.  I used an index card and a small mirror to make a sliding mirror in order to read the position of the weight w/o parallax error.  The whole shootin’-match was held on a stand that was salvaged from a cheap drill-press.  Measurements were performed by reading the distance between the movable weight and the pivot point, and entering that value in a Google Docs spreadsheet.

I definitely could have purchased a milligram scale for far less than this cost me in terms of spare time, but I learned a lot about scales in the process.  Almost all of it was stuff that I knew “in principle” — but actually building the scale infused my arm-chair knowledge with real-world experience, yielding an alloy whose properties seem to have exceeded its constituent parts.

The scale was nowhere near large enough to measure my satisfaction, but I estimate that this exercise yielded just about one metric ton of fun.

Maker Collider Event with NextFab Studio: TUESDAY

Option 1) Lasercut, Laser engrave, and LED-light-up your very own Snowflake
Option 1) Lasercut, Laser engrave, and LED-light-up your very own Snowflake

Join us on TUESDAY, December 20th, 7 pm – Midnight

Meet-and-Make, Hive76 and NextFab Studio Members
@ http://NextFabStudio.com/ @ 3711 Market Street

This “Maker Collider” event will be a great opportunity to make awesome stuff.

We had proposed these projects:
All details are here on the Wiki

After reviewing the projects here and those proposed by NextFab members it sounds like we will be doing some form of the Chess boards, the snowflakes, some robotics, and a bunch of laser-engraving. But what if you don’t like those? Come by anyway and you can rally troops for helping you on your own project(s).

NextFab Studio will have these staff members on hand throughout the event:
Chrinstine : Textile and Industrial Design ( fabric knowledge, product design,cad, sewing )
Ian : Electronics (pcb design/fabrication, coding, wiring, soldering, etc.)
Seth : Mechanical Engineer (handtools, cad, product design)
Brandon : Multi-Media Designer ( 3d printing, graphic design, product design, cinematography, cad)

Anything you want to do, you can do. AWESOME.

Check out all their equipment.

Oh, and there will be food too. Be there at 7 pm!!

To Join in on the Discussion, please join our mailing list

Pass Me Another One of Those Hive76s

Desktop Background, Pass Me Another One of Those Hive76s
Rendered Hive76 Desktop Background/Wallpaper

Well as we all know I’m completely infatuated with Blender, the open-source awesome-o 3D modeler, renderer, animator, and general all-around nice program. I’ve been making tons of high-res schematic diagrams for work related stuff, but it’s been so much fun that I’ve been exploring the intensely excellent Blender 3D interwebs community of fantastic artists and professional nerds.

So when I saw this tutorial video and instructional on an Energy Drink Ad by Andrew Price at Blender Guru, of course I immediately saw an opportunity for our favorite friendly local Maker Space to star in it’s own desktop background.

The Hive76 Can Label
The Hive76 Can Label

Adjusting the available .blend file and related stuff took a couple of hours, adjusting the rendering took a couple hours, and the final rendering took over an hour (2.4GHz Intel Core 2 Duo, not the fastest kid on the block anymore).

As you may know, the original Blender rendering engine is being deprecated, in favor of the new hyper amaziness that is the Cycles Rendering Engine. But before we leave behind the Blender Internal renderer for good, it’s nice to have one last Hurrah.

If you want to make your own version, here’s a package of all the source files (56.4 MB), they retain Andrew Price’s Creative Commons Non-Commercial Non-Ported Attribution License and I apply the same to my files that are in there. Rendered with Blender 2.60.0 build 41438.

Enjoy!

MMMM: Monitoring Motion

Eyes!
photo by peej

That time is once again upon us! This coming Monday, October the 10th, is our second installment of the Monthly Monday Microcontroller Madness series!

 

This month’s workshop will feature the concept of motion sensing in relation to microcontrollers. We’ll be taking a look at passive infrared sensors (PIR) for motion detection, ultrasonic range finders for distance measuring, and even looking at how to integrate a webcam into your Arduino project for motion analysis. These sensors and techniques are great for adding to your Halloween projects (wink, wink).

 

In addition to talking about motion, we will be offering our usual advice and guidance to those currently working on projects, or looking where to get started. All skill levels are welcome and we look forward to seeing you on Monday!

 

UPDATE: Here’s a link to the Arduino Reference page for the Parallax ultrasonic sensor and a code page for the Parallax PIR.

Manufacturer information can be found here and here, respectively.