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

Jan 192012

New in NYC Resistor vending machines

New in the NYCR vending machines are Teensy 2.0 boards. They have ATMega32U4 chips, which have the built in USB drivers and, via LUFA, can appear as any USB device, not just a serial communications device. Want to make a MIDI device show up as a USB keyboard? Or a core memory as a mass storage device? You can do that! The USB doesn’t consume a UART, so there is still a serial port available for interfacing with GPS or other external RS232 devices.

PJRC makes the Teensyduino plugin for the Arduino IDE and a set of compatible libraries so that you can use it with your Arduino sketches. Or you can drop into straight C and take full advantage of all of the AVR pins.

Update: They are very popular! Three were bought during Craftnight tonight.

 Posted by at 7:09 pm
Jan 152012

IBM 129 Card Data Recorder

This weekend PMF and I cleaned an IBM 129 Card Data Recorder and were able to fairly reliably punch cards once we were done. When we started it would frequently jam during feeding, mis-feed during the punch, and not cleanly stack the cards in the output bin.
Card Release

Most of the problem was thirty years of dust, card fiber and grime built up in the mechanisms. The output hopper was full of it and needed a good cleaning to reliably pick up cards into the output stack:
Output handler gunk
Output handler clean

Click for more inside

 Posted by at 9:19 pm
Nov 252011

Hexascroller ? LEDs

Adam and I upgraded Hexascroller to control 5 m of Adafruit RGB LED strip through a spare serial port connected to a Teensy 2.0 that drives the strip via SPI. Now when a new message is displayed, the accent lights switch to a bright flashing mode to attract attention, then they will return to soothing, slow color changing mode.

Click the “Read more” to see additional photos of the installation and setup. Continue reading »

 Posted by at 10:58 pm
Nov 122011

ATTiny10 programming

Using Darrel Tan’s Programming the ATTiny10 instructions and a SOT-23 breakout board by Raphael, I was able to flash one of these very small MCU chips. Given the small package, these programmable devices can be dropped just about anywhere on a circuit that a transistor would be used.

Unlike Tan, my FTDI breakout cable does not have DTR, so the reset pin on the chip needs to be pulled low manually to put it into programming mode, and the pinout adjusted. Full instructions after the break…
Continue reading »

 Posted by at 11:54 pm


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Nov 032011

Have you ever wondered how to make sense of hexdumps?

e1a02000e5d00000 e3500000012fff1e
e3a00000e2800001 e7d23000e3530000

Or been curious to know what exactly does a bxeq lr instruction mean in assembly?
Hex curious?

If so, then you should sign up for the introduction to assembly programming and reverse engineering class. You can learn assembly programming and machine architecture using reverse engineering techniques on your own code. In this class we will write code, compile it into an executable and then disassemble it to learn about registers, stacks, branches, function calls and argument passing, structs and other common idioms.

Experience with any programming language is required; the examples in the class with be in C, with dissassembly into ARM assembly. Bring your own laptop with arm-elf-gcc and associated binutils installed to follow along.

 Posted by at 8:22 pm
Oct 012011

3D printed x-stage
XY table dry fit

I’ve been inspired by the Lasersaur project to try building an XY table for laser cutting, Makerbotting, and light duty milling. The brackets, motor mounts and carriages are all 3D printed on NYCR’s Makerbot Thing-o-matic. Today I was able to put most of the pieces together for a dry fitting and found a few bugs — the carriages have too much play and will bind if pulled from the side, so the pull-pull belts will need to be moved to the inside of the rails, which will require all the carriages to be redesigned. The good news is that the printed teeth to engage the belt are well positioned to secure the belt under the rails without any additional hardware.

 Posted by at 1:15 pm
Jul 172011

Epilog command line laser cutter test

One of NYCR’s most popular weekly events is Lunar Laser Mondays using our Epilog mini-35 laser cutter. The only supported system is Windows with CorelDRAW and Epilog’s closed source driver, which doesn’t seem right for a hackerspace. Luckily, AS220 Labs has figured out how to talk to the Epilog using PJL. I’ve written a command line tool, epilog, that will translate the Postscript file into commands for the cutter.
Continue reading »

 Posted by at 3:45 pm