NYC Resistor

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.

As part of my on-going quest to fill my apartment (and hackerspace) up with semi-working 1970′s supercomputers, my effort to revive the Cray-1 supercomputer needs your help! Through the grapevine, I managed to get my hands on a genuine backup disk pack of the once-thought-extinct Cray Operating System (COS). Using my homebrewed disk reader I was able to make a copy of the disk, and the folks over at the internet archive (thanks Jason!) were kind enough to host it for me. Now is where you, kind reader, come in! Help me reverse-engineer the file system so I can recover the actual operating system files and take a step closer to towards booting this awesomely-useless machine!

Download it and get hacking!

Tonight at 21:00 eastern (02:00 UTC) Make:Live’s Hackerspace roadshow II visits NYC Resistor and other hackerspaces. From NYC Resistor you’ll see Alicia, Catarina and Shelby’s electronic art book, Mimi’s RFID blocking wallets, Charles’ TV-B-Gone gun and other cool projects by NYCR members.
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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. Read more

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…
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Inspired by Ranjit’s instrument-a-day (Make coverage), I’m writing a new wrist watch face every day for my progamable inPulse watch (more background). The full sources are posted online for others to build on.

Day 1 was a fixed point 3D rendering engine with a rotating Utah Teapot, day 2 was a rolling odometer or aviation altitude ticker display and day 3 is a 24-hour analog clock. This last one still needs some work.

We’re doing another session of our Soft Circuits class! Learn to make functioning electronic circuits using conductive threads and fabrics. You will leave with samples of the materials we use in the class and a warm glow in your heart. Or in your pocket. Beginners welcome!

http://www.eventbrite.com/event/1134540441

If you’ve been playing with the Arduino and want to figure out how to go to the next level, this Sunday’s Beyond Arduino class is for you.  Jarek Lupinski is going to be talking about how to breakboard your own designs using bare microcontrollers, how to program this chips using ICSPs, and how to downsize from the Arduino’s ATMega 328/168 to the less expensive ATtiny 45.

Details and registration at http://beyondarduino.eventbrite.com/

QRSS is a term used in ham radio to mean “very slow speed morse code”. QRPp means “using a very low power radio transmitter”. What happens when you combine these concepts? Small, simple, radios that can communicate over thousands of miles using about the same amount of power as a TV remote control.

The radio shown above is based on a kit by Hans Summers, G0UPL, that I picked up at the Four Days in May QRP convention. It uses a single-sided circuit board, with three transistors, one crystal, five toroids, a basic microcontroller, and a handful of resistors and capacitors. I added a 5v regulator, an LED to show the keying activity, and put it in an Altoids tin. The whole thing probably cost about $25 in parts, and took one evening to assemble.

After building it and tweaking it to get it on exactly the right frequency, I hooked it up to the dipole on the roof of NYC Resistor, and flipped on the power switch. My 100 milliwatt signal went up into the sky, bounced around between the ionosphere and the ocean a bit, and was picked up by a radio operated by Johan, ON5EX, in Belgium. He runs what is known as a “grabber” — a radio and computer combination that monitors the QRSS portion of the 30m band, converts the signals into digital spectrographic images, and publishes them on the internet.

Here is a screen capture from Johan’s website shortly after I powered on my transmitter. It shows about 100Hz of spectrum (frequency is on the vertical axis) over 11 minutes (horizontal axis). My signal is in the center of the graph. It’s my call sign, W2VV, sent repeatedly in morse code (·–– ··––– ···– ···–) at about 10.140015 MHz. If you listened to this signal as audio, you would mostly hear static. The horizontal lines you see in the graph would come out as tones. The higher the line, the higher the pitch of the tone. My signal would sound like a tone that changes pitch ever so slightly up and down as the dots and dashes are sent. However my signal would probably be so weak as to be inaudible through the static. It is only discernible when converted to visual form and then compressed over a long period of time.

Belgium is about 3600 miles away from New York, which means this transmission achieved an amazing power efficiency of 36,000 miles per watt. Also, it occupied just a tiny sliver of bandwidth — only 5Hz, meaning many other people could share the same range of frequencies without interfering with each other. However you don’t get something for nothing in life, and the tradeoff in this situation is that very little information was sent. It took six minutes just to send my four-character callsign. Still, that’s not a bad deal for a $25 radio that fits in your pocket.

Visit my Flickr page for more photos of the build. Better yet, come to our Ham Party on Saturday and see it for yourself! And if you can’t make it to our place, visit one of the hundreds of other ham radio clubs across the country hosting public events this weekend in honor of ARRL Field Day.

72/73, Dave W2VV

During Hackday I worked on a display for the Stabby ID.

I have six or so HDSP 2111 units lying around. They also come in green and red led models.

Read on for Schematic and Demo Arduino Source
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