When you think of old school handheld games, you probably imagine something like Nintendo’s Game Boy line or the Sega Game Gear. But outside of these now iconic systems, there was a huge subculture of oddball handheld games vying for a slice of a teenager’s weekly allowance. Many of these were legitimately terrible and frankly aren’t worth remembering, but a few offered unique features that were arguably ahead of their time.
One such game was Hasbro’s short-lived POX. As explained by [Zachary Ennenga]the game didn’t spend much time on store shelves, as its core concept of defeating undetectable alien invaders determined to destroy our way of life proved more than a little problematic when it launched in September 2001. That’s not to say it wasn’t cool ideas, such as a wireless ad-hoc multiplayer feature that allows your game to fight autonomously against other devices that came close.
Fascinated by this feature since youth, [Zach] set out to study how this relatively inexpensive children’s toy managed to pull this off when even flagship handheld consoles still used physical link cables for multiplayer. He was aided in his quest by a particularly useful patent, which not only gave him clues about the frequency, data rate, modulation and encoding of the RF signal, but even explained the game’s logic and general structure. Much of what was in the document seemed like wishful thinking on Hasbro’s part, but reading through the marketing pitch still revealed some salient technical details.
Armed with an RTL-SDR, GNU Radio, Inspectrum and some Python, [Zach] managed to identify the signal and start the process of decoding it. This is where things get really interesting, as the details of his reverse engineering process are widely applicable to all kinds of unknown RF signals. Even if you’re like most people and have almost zero interest in failed handheld games from the early 2000s, it’s well worth a read. The same techniques he uses to figure out the name and physical characteristics of the invisible enemy his game sends may one day help you figure out how to manipulate the data from the wireless weather station in your backyard.
As soon as he found out the main parts of the protocol, [Zach] proceeds to create its own packets and broadcast them in such a way that the real hardware will recognize it. He even comes up with a code that will automatically fight games that wander within Yardstick One’s range, which could come in handy during the inevitable POX renaissance.
While this may seem like a lot of effort to put into a game most people have never heard of, we’d like to remind you that some of the greatest hacks to ever grace these pages were born out of similar pursuits. Even if you are the only person in the world who directly benefits from your current line of research and experimentation, there are still many like-minded people in this community who are only too happy to cheer you on from the sidelines.