Tweet Messages from Punch Cards

It all started with a conversation about the early days of computing. The next thing he knew, [Tim Jagenberg's] colleague gave him a stack of punch cards and a challenge.  [Tim] attempted to read them with a mechanical contact and failed.  Undeterred, he decided to make a punch card-to-keyboard interface using optical parts from disassembled HP print stations.  Specifically, he took apart the slotted optical interrupter switches to use their IR-LEDs and photo-transistors. Next, [Tim] drilled holes into two pieces of plastic, gluing the LEDs on one piece of plastic and the photo-transistors on the other. The photo-transistors tell the Teensy 3.1 whenever a hole is detected.

[Tim] developed an interpreter on the Teensy that reads the punch card according to IBM model 029 keypunch codes. The Teensy enumerates as a USB keyboard when connected to a computer. As a punch card is read, the Teensy outputs the decoded characters as key presses.  When a punch card has been completely read, an ‘Enter’ key press is transmitted.  Tweeting the punch cards is no more complicated than typing the text yourself. Naturally, the first message posted on Twitter from the stack of punch cards was “Hello World!”  [Tim's] binary and source code is available for download on Github.

We’ve enjoyed covering the backstory of the punch card and a previous project reading these cards using a digital camera setup. It’s always interesting to see the clever ways people use current technology and can-do attitude to read data from obsolete systems that would otherwise be lost.  We wonder what is on the rest of those punch cards?  Let’s hope [Tim] has more punch card tweets soon!

USB dongle generates and enters your passwords so you don’t have to

usb-password-dongle

Like many businesses out there, [Joonas Pihlajamaa’s] employer requires him to change his password every few months. Instead of coming up with a complex, yet easy to remember password again and again, he built a small USB device to do the work for him.

He dismantled an old USB memory stick, fitting it with an ATtiny85 with its required components on a small piece of perfboard. Using the knowledge he gleaned from his previous USB HID tinkering, he programmed the ATtiny to act as a USB keyboard which enters his password for him whenever he plugs it in.

The USB dongle not only types his password in for him, it can generate a new password with a few simple keystrokes whenever he desires. Obviously it merely takes someone getting their hands on his USB stick to compromise security, but it does beat a Post-It under the keyboard any day.

Continue reading to see a short video of his USB password dongle in action, and be sure to swing by his site for more details on how it was all put together.

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