I like to take things apart. Sometimes they work when I'm done. I've been a member of NYC Resistor since 2010 and you can see more of my projects at

Hack Holyoke

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Nov 102014

Hardware checkout at Hack Holyoke
Last Friday was the Hack Holyoke 24-hour embedded systems hackathon, held at Mt Holyoke College. Of the 200 participants, well over half were women from the Seven Sisters schools and many were attending their first hackathon.

Hack Holyoke dance party
One of the distinguishing features of this hackathon was a 2am dance party! Every event should include one.

You can read @HackHolyoke twitter stream and read on for some photos of a few of the teams.

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Sep 042014

Hopper Interactive Disassembly
Want to get started with reverse engineering on i386, x86-64 or ARM systems? The Hopper disassembler makes it easy! Or at least easier to understand what is going on in binaries, firmware dumps and other random executables that you might encounter.

This four hour class is taught by Trammell Hudson, the original author of the Magic Lantern firmware for Canon DSLR cameras, and will cover initial exploration of files, annotating functions, discovering common patterns and using the control-flow graph / pseudo-code generator to understand what the assembly is doing.

Experience with programming, but not necessarily assembly language, is necessary, as is a Mac or Linux laptop. Buy your tickets here!

Solder paste

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Jul 142014

MOSFET level shifters
If you find yourself soldering tiny SMD packages, like these dual MOSFETs, you might pull out the microscope and get to see the solder paste for what it really is:
Solder paste under the microscope
So many tiny balls of solder! And as all of the microscopic spheres melt, surface tension pulls the blob onto the pads in the most amazing way.

Jun 032014

Mega Mario

Megascroller is the 512×64, 32-sided upgrade to Octoscroller, which was the eight sided RGB update to the venerable six-sided red LED Hexascroller. Megascroller is featured as one of the art pieces at the upcoming Interactive Show — on the giant cylinder you can play different video games in the round. Unlike normal side-scrollers, you have to move sideways to keep up with the onscreen characters. Here’s a video as we play-test Mario (source code) and discuss some tweaks to the game to enhance the fun (there is some interaction with the camera shutter that makes artifacts in the movie).

Buy your tickets now! and come see Megascroller plus lots of other fun interactive art at the 2014 Interactive Show. The doors open this Saturday at 8pm! The show is over and was great fun! Here’s a video of Mario being played in the round sometime late last night:


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Jun 022014

Two weeks ago we salvaged two PDP-11/34 minicomputers, VT1xx terminals and assorted parts. Since then we’ve spent some quality time in the 1970s, cleaning Unibus contacts, reseating cards and replacing bad capacitors in the VT100 analog boards. Both of the CPUs start up fine and we’ve been able to read data from all of the RK05 and RL01 drive units. Still haven’t touched the tape drives, so no digitized monkey brains yet. Instead, here is a video of running Colossal Cave Adventure compiled from the original FORTRAN IV sources under RT-11v4 on our PDP-11/34:

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May 152014

PDP-11/34 cabinets

We rescued two PDP-11/34 computers and their associated equipment from a storage unit in the Bronx and have been working on getting them running again. The computing system included multiple RK05 hard drives, two RL02 decpack drives, a TU11 tape drive and tons of media, including “digitized monkey brains“. Read on for more details and the exciting boot sequence.
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May 052014

Please allow additional travel time.Companion Cube
Hexadeca scrollerDisorient Pyramid, mini version

A few months ago we introduced Octoscroller, NYC Resistor’s eight-sided RGB LED matrix display built with jumbtotron RGB LED matrix panels. The interface “cape” has been reworked twice and the LEDscape source code has been refined to handle various arrangements of panels, from rectangular displays to larger polygons to six-sided cubes and minature pyramids. We’ve also updated the code to receive from OPC and other transmitter formats, in addition to local drawing into a user-space framebuffer.

Jumbotron time!
The good news is that we finally have the supply of panels and control boards to offer a class on building your own mini-jumbotron or other shaped display! Included in the class fee are eight of the 32×16 RGB panels, a BeagleBone Black with the Octoscroller^2 cape (capable of driving up to 64 panels at 30-60Hz), a 10A power supply and the wiring to put it together.

You can print or lasercut your own brackets based on how you want to arrange your panels — OpenSCAD and STL files for the octagon, cube and flat brackets are in the source, and Misumi 15mm extrusion works great for larger structural pieces.

HandcraftedTrammell finishing his mini-Disorient pyramid display of LED matrices.
I’m Trammell Hudson, the primary author of the LEDscape code and the designer of the controller boards and I’ll be leading the three hour workshop at NYC Resistor on May 24th. In the class we’ll solder together the board, install the software on the BeagleBone Black, wire up the eight panels and write a simple program to draw on the panels. I’ll also walk through the PRU firmware that handles the real-time interfacing, although this programming experience isn’t required. Buy your tickets here!