As the Jerusalem mini Makerfaire approached, [Avishay] had to come up with something to build. His final project is something he calls ASTROGUN. The ASTROGUN is a sort of augmented reality game that has the player attempting to blast quickly approaching asteroids before being hit.
It’s definitely reminiscent of the arcade classic, Asteroids. The primary difference is that the player has no space ship and does not move through space. Instead, the player has a first person view and can rotate 360 degrees and look up and down. The radar screen in the corner will give you a rough idea of where the asteroids are coming from. Then it’s up to you to actually locate them and blast them into oblivion before they destroy you.
The game is built around a Raspberry Pi computer. This acts as the brains of the operation. The Pi interfaces with an MPU-9150 inertial measurement unit (IMU). You commonly see IMU’s used in drones to help them keep their orientation. In this case, [Avishay] is using it to track the motion and orientation of the blaster. He claims nine degrees of freedom with this setup.
The Pi generates the graphics and sends the output to a small, high-brightness LCD screen. The screen is mounted perpendicular to the player’s view so the screen is facing “up”. There is a small piece of beam splitting glass mounted above the display at approximately a 45 degree angle. This is a special kind of glass that is partially reflective and partially translucent. The result is that the player sees the real-world background coming through the glass, with the digital graphics overlaid on top of that. It’s similar to some heads-up display technologies.
All of the electronics fit either inside or mounted around a toy gun. The display system was attached with a custom-made fiberglass mount. The code appears to be available via Github. Be sure to watch the video of the system in action below.