Nov 032013
 

Photo by flickr.com/cbrobotics

I’d like to share a neat Eagle hack for all our the people who have taken our Eagle CAD classes (myself included) and our Eagle-using friends.

BOM-EX is nifty little ULP (User Language Program) that extends the functionality of the built-in BOM ULP. BOM-EX not only helps you assemble a coherent BOM (Bill of Materials) right from your Eagle schematic, but it also makes it easy to assemble a database of parts, and associate those parts with parts numbers for DigiKey, Mouser, Newark, etc.

I made a nice little script that lets me build my BOM database without ever leaving the DigiKey website…

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 Posted by at 2:26 pm
Oct 052013
 

There is an an earth-shattering kaboom.
Our laser cutter is suffering from the need of a replacement part and will probably not be working by Monday. You’re still welcome to come over for our regular open Thursday night, but you may not be able to do any laser cutting, so bring your arduino or your hyperbolic crochet instead.
Our laser has been restored to full operation. Do not attempt to bring your hyperbolic crochet to laser night. We apologize for the inconvenience. Thanks for your patience!

 Posted by at 11:51 am

Octoscroller

 Uncategorized  6 Responses »
Sep 122013
 

Octoscroller temporary installation

Hexascroller has been a central fixture at NYCR for the past few years, with a few ups and downs. It’s replacement, Octoscroller, improves on our classic message alert polygon by having two more sides and two more colors of LEDs.

The userspace application renders images into a shared memory frame buffer, or in this case receives UDP packets containing video images from the Disorient Pyramid transmitter. The PWM algorithm can do between eight and sixteen levels of brightness for each color, producing approximately 12-bit color.

See it in person at MakerFaire in NYC this year and read on for details of how to wire up a driver for the panels, as well as a walkthrough of some of the PRU code.
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 Posted by at 9:41 pm
Sep 052013
 

Party at the Disorient Pyramid

This year the Disorient Camp at Burning Man built a 7m tall pyramid with over half a kilometer of LED strips. Several artists developed patterns for the panels, including Disorient founder Leo Villareal and Jacob Joaquin from Fresno Idea Works. Every night there was a party in front of the pyramid, with bicycles blocking the entire Esplanade.

The pyramid was visible from just about everywhere on the playa and served as a great beacon for finding the camp after a long night out. Read more for the technical details of how it was constructed and links to all the source code.
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 Posted by at 11:07 pm

Oscilloscope class

 Uncategorized  1 Response »
Aug 042013
 

Diagnosing EL wire with a DSO Nano v3

One of the most powerful tools in debugging circuits is the oscilloscope — it allows you to visualize your analog and digital signals at millisecond or microsecond time scales. This 18 August class at NYC Resistor will teach you basic operation of a handheld oscilloscope: topics include how to setup different time and voltage scales, how to configure the trigger modes to capture fleeting signals and how to use the cursors to measure various qualities of the signals. We’ll also show how to use the ‘scope to trace a signal through a circuit to identify some common problems.

Multimeter amperage measurement

The other most valuable tool in your electrical test equipment toolbox is a multimeter for measuring the instantaneous values of three important electrical measurements: voltage, amperage and resistance. This class covers all three of these as well as the very important “beep mode” to check for electrical connectivity.

Get your tickets here! The class fee includes both a compact multimeter and a DSO Nano v3, an Open Hardware design that is a great getting started oscilloscope. With these in your toolbox you’ll be able to diagnose all manners of circuit issues.

 Posted by at 3:12 pm

LEDscape

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Jul 272013
 

LEDscape test

Are you building a giant LED display for your hackerspace or Burning Man and need a way to control multiple kilometers of LED strips? Are you tired of running massive USB hubs of Teensys for each row? Then you might be interested in my LEDscape code for the BeagleBone Black to drive up to 500 meters of WS2811 RGB LED strips at 30fps.

On the Teensy 3, Paul’s OctoWS2811 makes very clever use of three DMA engines to generate the bit-train for the WS2811 LED strips, but only supports up to eight strips. Beth’s FadeCandy improves on Paul’s work and has a great frame rate with beautiful interpolation (and a custom USB protocol to pump pixels fast enough to keep up with the frame rate), but the temporal dithering and expanded colorspace features run into frame rate and memory limitations at strips beyond 64 pixels.

The BeagleBone Black has far more memory than the embedded AVRs (512MB versus 16KB) and the AM335x ARM Cortex-A8 has a killer feature: two built in PRU (“Programmable Realtime Units”). These are embedded real-time microcontrollers built into the ARM core with full DMA to main memory and control over all of the IO pins. This afternoon I hacked up a quick proof of concept in PRU assembly that use one of the units to drive 32 of the WS2811 strips at full speed with zero CPU load and easy double-buffering of the image. The best parts of writing for the ARM instead of the AVR is that there aren’t any issues with running out of memory for image processing and there is built-in ethernet for OSC or other visualization libraries.
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 Posted by at 11:39 pm
Jul 052013
 

Freddie

This is a project I made for my two year old nephew. He really likes bright lights and buttons, so I wanted to make something special for him with plenty of both. I made it from a clear box so he could see the parts inside. As he’s a curious boy, I wanted this to spark a lifelong curiosity about how things work.

Since this toy is fully programmable, it can evolve as he gets older. The behavior now is simple: change light colors and patterns based on the knob state and button presses. Once he’s a little older, I can reprogram this to be a memory game where he has to reproduce certain patterns. If it survives early childhood, perhaps I can even teach him to program it himself…

I wrote more about the construction here.