Halo Energy Sword

March 24, 2009 / 6 Comments

If you read about that sort of thing, you may remember last fall Master Replicas announced a Halo Energy Sword that would feature similar functions as their ForceFX Lightsabers (powerup/down sounds, motion activated sound, animated lights). The promised release date was the holiday season 2008.
There is another company that makes realistic Halo toys, this is the same company that made a plasma pistol and plasma rifle that are superb. They also announced an energy sword in 2007 with a 2008 release.
Here we are in 2009 with no product from either company. I had to do some major digging to learn both these products were canceled and will never be released. Killed for either licensing or safety concerns.

Based on the demo videos released by Master Replicas, it seems possible for me to create my own prop with similar capabilities. Hit more info for details.

Update: August 2009 – See completed project details.

This project is fairly large for me and needs to be broken down.

Modeling and Plastic Molding

Most of the Halo models are freely available and have even been converted into a format that can be printed out. Ready to be cut, folded, and glued into a 3d shape. I plan to adapt this process to recreate the sword’s handle. So far, I have the blade handle shape created and I filled it with expanding insulated foam for strength (paper is not strong).

The next step is to cut this model in half and place on a vacuuform machine (which I don’t have). The resulting plastic shape will be glued or screwed together to create a hollow plastic handle (to house the electronics) that is durable and ready to be painted. There are plans available online for home vacuuform machines that can be built for less than $50 and use a shopvac.

Lights and Acrylic

I need to experiment with some scale arcylic pieces to determine the best method of lighting an acrylic blade, but the goal is to animate some LEDs that illuminate the blade so that the blade will appear to extend and retract.

Diffuser Options
The acrylic has a fiber optic like property when light shines near the edge, the light will bounce around inside of the arcylic until it finds an imperfection to illuminate. A diffuser is used to catch the light.

  1. Sanding the acrylic, will give the acrylic a frosted look.
  2. White adhesive laminate, this is best suited for a multi layered acrylic that is lighted internally

LED Placement Options

  1. A row of LEDs on the interior or exterior edge or both. The LEDs can be covered by a strip of black or white tape. May create “hot” spots along the edges.
  2. An array of LEDs sandwiched between acrylic on either side. Will use hundreds of LEDs and give the most even light.

Whatever I end up doing, the LEDs will be animated. I have a circuit in mind that will do the extend effect very nice, but I am also looking into a microcontroller (depends how the sound effects tests go). As far as I can tell, I will be the first hobbiest to attempt something like this for a Halo prop.

Sound Effects

Besides the lights, this is the most interesting part of the project and is fast becomming the most difficult. I have seen on various forums people harvasting the sound board from electronic sword toys and reusing them for this purpose. I was unable to find any local stores that sold appropriate electronic toy swords. I can find several online but refuse to buy anything before I use it in hand, so I know the light patterns and sounds it will make (don’t want my halo prop making pirate shouts, haR!).

My next option is compiling my own sound effects and playing them back in sequence. This is a lot easier said then done. The actual sounds can not be dumped from the game only recorded while it is running. The best quality sounds I have found are actually from that MR demo video. I plan to record this to some .wav files for the sounds they demonstrated.

As far as playing them back, that is an interesting request. I have a few options including MP3 players, voice chips, and microcontrollers. An MP3 player would be too slow and would have limited playback options, similar story with the voice chip. That is why I am leaning toward a microcontroller. A microcontroller could be loaded with converted wav files and play them back at a sample rate, it could also be used as a substitute for the light circuit and give access to more animation patterns.

The problem with using a microcontroller is more an issue of experience with sound playback. I’ve only done it once before on an 8085, which I don’t have. What I do have is a dev board left over from my college days for an ATMEGA32 chip. There is a great website available for enthusiests of the atmel microcontroller manufacturer and the free software suite, AVRstudio. The website is AVR Freaks and after doing some searching I found some free source for playback of converted wav files. The assembly source is for a different processor, but checking the spec sheets, they are not only compatible, but my chip offers more features and four times more flash memory (32kB vs 8kB for more sound clip storage).

To bad for me, before I left college I accidently erased my serial bootloader. So now I need an ISP programmer ($40). While I’m at it, I might as well also purchase some extra crystals and power transitors so I can build up a stripped down dev board for a prototype circuit. Here is an ordered list of the planned evolution of my program.

  1. Get the sample code working playing back the sample wav file
  2. Get the sample code to playback my own wav file
  3. Call the assembly sample code from a c coded main loop
  4. Playback two wav files back to back
  5. Playback a wav file in a loop
  6. Playback starts on button press, playback stops on button release
  7. Put it all together: Wait for button press, playback powerup sound, playback on sound in loop, wait for button release, playback powerdown sound, wait for button press.
  8. Add timer interrupt to control LED animations

Motion Sensors

I am not really sure, what I will do here. This is more of a future development. I have seen motion sensors before, they consist of a week spring surrounded by metal, movement causes the spring to contact the metal sides. I could use something like this and set an interrupt to triggure additional sound effects (swoosh, swish).

Some other options, tilt switches and accelerometers. I don’t think a tilt switch is what I am looking for, in the tilted position, the switch is always one.
The accelerometer has some technical hiccups. It will detect motion very nicely on all 3 axis and the cheaper models are sensitive to small motions (less than 3G). The problems come in that this is an analog device and to be cost effective, only is available in surface mount packages. The analog side can be handled by the sound microcontroller and the ADC inputs, but the surface mount… that will need some more thought.

Battery Format

Probably a 9V for now, may expand to a recharchable NiMH or an impossibly small lithium poly.

Current Progress

Current progress and project notes can be found on my forum.