In-Depth With Frog Designs’ TRON Cycles

During our time at SXSW 2012, Ricky and I were able to spend some time at the Dorkbot & ATX Hacekerspace event at SXSW Create. During our time there we met Matt Franks the Senior Interaction Designer with frog (formerly frog design). We highlighted his TRON Cycles a little bit in our SXSW recap, but Matt was nice enough to dive a little deeper into how they created this large scale version of the classic arcade game:

For the past 10 years, frog (formerly frog design) has hosted the SXSW Interactive opening party –  celebrating the artistic and interactive side of cutting edge technology.  This years event featured large scale physical / mechanical versions of classic arcade games and was dubbed “The Makers Arcade”.

Frog Design's TRON Cycles

In the staging area the night before the party.

It included our own take on the arcade game Tron. For anyone not familiar with the classic arcade game, two people race to the death in a digital arena on futuristic motorcycles.  As the players travel the arena, ribbons of light trail behind their respective vehicles. The first person to hit a ribbon of light, or an arena wall, will crash their bike – ending the game.

Frog Design's TRON Cycles

Jared Ficklin and Ivey Lian – during construction and testing.

For our version of the game, we thought it would be really funny to have grown men and women riding something that looked like an oversized big-wheel. We also wanted to explore the convergence between physical and digital game play by requiring participants to pedal their way forward in the game. This allows players to vary the speed of their bike and requires some element of endurance, drastically altering the players experience when compared to the original arcade game.

Frog Design's TRON Cycles

The Trikes were built from the ground up with used bicycle parts.

Frog Design's TRON Cycles

After a failed attempt at creating a fiberglass body, we used 1/2″ sheets of painted plywood to give the illusion of form and provide volume when viewing the trike at an angle.  With the money we saved by ditching the fiberglass, we were able to double down on the LED’s for visual effect.

Frog Design's TRON Cycles

The entire experiences uses Two Arduino Duemilanoves (purchased at RadioShack) to deliver data to the computer and control the ring of lights around each wheel. As the rider pedals, two rings of 12v LED’s alternate ON and OFF, creating the illusion that the wheel is spinning.

An early version of the wheel created this illusion with a relay switch. Because a relay switch is a mechanical switch, it made a really cool clicking sound as it was alternating.  Unfortunately this type of switch didn’t work because it can not maintaining high frequencies (alternating ON / OFF really quickly) over time.

Frog Design's TRON Cycles

The frequency problem was solved by using TIP3055 NPN Transistors (from RadioShack) instead of the relay switches.  The transistors work flawlessly for alternating the lights at a high frequency.  Allowing us to create the illusion of speed with a stationary wheel.

The second Arduino delivers data to the computer.  It is connected to a potentiometer and a reed sensor on each bicycle.

Frog Design's TRON Cycles

Each bicycle has a potentiometer affixed to the bottom of the handle bars.  The potentiometer rotates as the rider turns the bars, sending a value to the Arduino that is interpreted as the degree of turning.

Frog Design's TRON Cycles

Each bicycle has two reed sensors attached to the frame, and 16 earth magnets attached to the fly wheel.  As the wheel turns, the magnet trips the reed sensor, sending a pulse back to the Arduino.  The Arduino uses an attach interrupt sequence to record the number of pulses ever 350 milliseconds.  With this value, it is able to approximate the pedaling speed.

Frog Design's TRON Cycles

Why Two Arduinos? – The processor on a single arduino wasn’t fast enough to keep up with all of the sensors on both bikes and operate the transistors to create the spinning LED illusion.  We used AttachInterrupt to trigger a function each time a magnet tripped the reed sensor and quickly discovered that when both bikes are being pedaled very rapidly, the Arduino will get flooded with data and locks up.  So by splitting the load across two boards, we were able to stay within the processing limitations of the arduino.

Frog Design's TRON Cycles

The bikes are connected to the Arduinos through Cat5e cables and RJ45 jacks.  This makes setup and tear down really simple.

Frog Design's TRON Cycles

The result is an addictive, high energy, game that is fun for the riders and the audience.  Each rider has their own “over the shoulder” view, while the audience can see the classic top down view – just like the original arcade.

Here is a quick overview video and some examples of people playing:

Be sure to check out our documentary on the party & other experiences here.

Electro Tennis

Crowd Connect 

A big thank you to Matt (@franknatic) for showing us how he created this addictive and high energy game. Leave a comment below and let us know what you think of this large scale game! 



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