TRON Handheld POV Display

2010

I am a fan of the 1982 movie Tron which I saw as a teenager and I am very excited about the sequel TRON: Legacy. A friend and I are planning to attend the opening here in Thailand and thought it would be fun to take something suitably geeky along with us to the theatre.

My friend has a fiber optic frisbee which fits well with the whole TRON theme and I thought about making a costume or T-shirt using EL Wire but thought I might end up looking like the Tron Guy. Instead, I built this handheld Persistence Of Vision (POV) display which you can wave through the air to display the movie's logo (amongst other things).

To the left of the lowest LED is a small button on the front of the box that can be used to switch between different patterns. You can read on below to see the patterns I currently have programmed into the display or to find out more details about how it works.

When I decided to build the POV display I drew a quick picture in a paint program and decided that I could produce a reasonable facsimile of the new TRON logo with a 10 pixel high display. The images below were produced using a long exposure "fireworks" mode on our digital camera to capture a single wave of the handheld display (which is why I look like a ghostly apparition in the background of some of the pictures):

The French electronic music duo Daft Punk have scored an original soundtrack for TRON: Legacy and they also have a cameo in the movie. Here is some love for Daft Punk and the logo from the original movie:

I also added some fun patterns - "I love U" (in case your wife happens to like TRON movies too), space invaders, and Pac Man:

Inside the Box

I've been fascinated by POV displays for a while and this was the prefect excuse to build one. The display is built around an Arduino Duemilanove and a schematic is shown below. I'll update the page with some more construction details over the next few days.

Schematic diagram for the handheld POV display

Thes are some pictures I took during construction.

Underside of the LED board with the current limiting resistors

Side view showing the LED board attached to the Arduino

Apart form the LEDs the box also contains an ADXL345 triple axis accelerometer breakout board which is used to synchronise the display as it is waved in the air.

ADXL345 breakout board attached to the Arduino

Right angled header with resisitors and ground connection

Side of the header attached to the ADXL345 breakout board

The first graph shows the Y-axis acceleration during some test swings I made using the ADXL345 accelerometer in the +/-2g range. Notice the clipping at the 2g limit (+/-511). The second graph shows the Y-axis acceleration using the +/-8g range at full resolution. The display can draw the pattern left-to-right or right-to-left based on the direction in which it is being swung. The last image shows the result of multiple waves during a long-exposure shot.

Acceleration graph showing swings recorded using the +/-2g range

Acceleration graph showing swings recorded using the +/-8g range at full resolution

Long exposure shot of the handheld TRON POV display in action

Here's the original artwork I used to create the TRON logo. I'll provide some more details about encoding the patterns when I update the page.

You can download the Arduino sketch and some pattern files to use with the display from GitHub.

Other Projects

You may also be interested in reading about playing lightcycle games using PVC-pipe handlebars or real motorbikes, or some of my other projects: