Hacking The Thotcon 0x8 Badge

[Kenjo] attended Chicago’s Thotcon this past week and has started hacking the convention badge and detailing what he learned. Thotcon’s badge, designed by [Jedha] and programmed by [John Wallis] of Workshop 88, is packed with the requisite electronic hardware and cryptic clues. There are four NeoPixel LEDs, three pots, and a micro USB, all run by an ATmega32u4.

The stock firmware is a game called tesserHack, a maze game using the three pots for navigation. You can also connect via USB to play through the serial console, and this version includes a map view and help menu.

[Kenjo] who previously hacked the Thotcon 0x6 badge, accidentally deleted the stock firmware on this year’s badge, so he used a Bus Pirate as an ISP to burn the Arduino boot loader back on, and has started mapping out the pots and LEDs. If you’re interested in helping out, check out the project on Hackaday.io. [Thanks, gigawatts]

How A Hacker Remembers A PIN

If you have more than a few bank cards, door-entry keycodes, or other small numeric passwords to remember, it eventually gets to be a hassle. The worst, for me, is a bank card for a business account that I use once in a blue moon. I probably used it eight times in five years, and then they gave me a new card with a new PIN. Sigh.

Quick, What’s My PIN?

How would a normal person cope with a proliferation of PINs? They’d write down the numbers on a piece of paper and keep it in their wallet. We all know how that ends, right? A lost wallet and multiple empty bank accounts. How would a hacker handle it? Write each number down on the card itself, but encrypted, naturally, with the only unbreakable encryption scheme there is out there: the one-time pad (OTP).

The OTP is an odd duck among encryption methods. They’re meant to be decrypted in your head, but as long as the secret key remains safe, they’re rock solid. If you’ve ever tried to code up the s-boxes and all that adding, shifting, and mixing that goes on with a normal encryption method, OTPs are refreshingly simple. The tradeoff is a “long” key, but an OTP is absolutely perfect for encrypting your PINs.

The first part of this article appears to be the friendly “life-hack” pablum that you’ll get elsewhere, but don’t despair, it’s also a back-door introduction to the OTP. The second half dives into the one-time pad with some deep crypto intuition, some friendly math, and hopefully a convincing argument that writing down your encrypted PINs is the right thing to do. Along the way, I list the three things you can do wrong when implementing an OTP. (And none of them will shock you!) But in the end, my PIN encryption solution will break one of the three, and remain nonetheless sound. Curious yet? Read on.

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Measuring Walking Speed Wirelessly

There are a lot of ways to try to mathematically quantify how healthy a person is. Things like resting pulse rate, blood pressure, and blood oxygenation are all quite simple to measure and can be used to predict various clinical outcomes. However, one you may not have considered is gait velocity, or the speed at which a person walks. It turns out gait velocity is a viable way to predict the onset of a wide variety of conditions, such as congestive heart failure or chronic obtrusive pulmonary disease. It turns out, as people become sick, elderly or infirm, they tend to walk slower – just like the little riflemen in your favourite RTS when their healthbar’s way in the red. But how does one measure this? MIT’s CSAIL has stepped up, with a way to measure walking speed completely wirelessly.

You can read the paper here (PDF). The WiGate device sends out a low-power radio signal, and then measures the reflections to determine a person’s location over time. Alone, however, this is not enough – it’s important to measure the walking speed specifically, to avoid false positives being triggered by a person simply not moving while watching television, for example. Algorithms are used to separate walking activity from the data set, allowing the device to sit in the background, recording walking speed data with no user interaction required whatsoever.

This form of passive monitoring could have great applications in nursing homes, where staff often have a huge number of patients to monitor. It would allow the collection of clinically relevant data without the need for any human intervention; the device could simply alert staff when a patient’s walking pattern is indicative of a bigger problem.

We see some great health research here at Hackaday – like this open source ECG. Video after the break.

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LED Tail Lights For Improved Motorcycle Visibility

Motorcycles are hard to see at the best of times, so riders are often concerned with making themselves as visible as possible at all times. [Josh] wanted to do this by creating a custom tail light for his Ducati 749.

The tail light is based around SMD LEDs, mounted in acrylic to diffuse the light. The construction is beautiful, using custom PCBs and carefully machined acrylic to match the lines of the bike.

As far as warning lights go, a brighter light will be more obvious in the day time, but could actually hinder visibility at night by blinding other road users. To this end, [Josh] built the tail light around an ATtiny 45, which could be programmed with various routines to optimise the light level depending on ambient conditions. Another feature is that the light’s brightness pulses at high frequency in an attempt to attract the eye. Many automakers have experimented with similar systems. The ATtiny controls the lights through a PCA9952 LED controller over I2C. This chip has plenty of channels for controlling a bunch of LEDs at once, making the job easy.

Overall, it’s a very tidy build that lends a very futuristic edge to the bike. We’ve seen [Josh]’s work in this space before, too – with this awesome instrument display on a Suzuki GSX-R.