This project was the result of an urge to contribute something to the Creative Games section of my kids’ elementary school fair. The kids loved it for it’s simple old-school game aesthetic mixed with Wii-style and Kinect-style video game control. It’s a spin-off project of an earlier Ball & Plate experiment mentioned here in the Instructables forums.
The machine is an over-sized (1200mm (48”) diameter) version of the traditionally hand-held game where the object is to tilt a circular disc to move one or more balls though to the center of a maze. The circular board is supported by a stand with a centrally mounted gimbal, and controlled by either a wired hand-held contoller, an Android phone, or by body movements.
An Arduino microcontroller is used to monitor the player's actions and then adjust the tilt of the board to match. The wired controller uses an accelerometer module. The Android phone controller uses the in-built accelerometer and a custom app made with Processing to communicate via bluetooth with the Arduino. The body controller uses two sonar proximity sensors to detect how far the operator is from a central position to determine how much to tilt the board.
The board is tilted using two gearmotors pulling on strings attached to the underside of the board – one for front and back, and one for left and right. An accelerometer is attached to the underside of the board to provide the position feedback to the Arduino.
The machine is an over-sized (1200mm (48”) diameter) version of the traditionally hand-held game where the object is to tilt a circular disc to move one or more balls though to the center of a maze. The circular board is supported by a stand with a centrally mounted gimbal, and controlled by either a wired hand-held contoller, an Android phone, or by body movements.
An Arduino microcontroller is used to monitor the player's actions and then adjust the tilt of the board to match. The wired controller uses an accelerometer module. The Android phone controller uses the in-built accelerometer and a custom app made with Processing to communicate via bluetooth with the Arduino. The body controller uses two sonar proximity sensors to detect how far the operator is from a central position to determine how much to tilt the board.
The board is tilted using two gearmotors pulling on strings attached to the underside of the board – one for front and back, and one for left and right. An accelerometer is attached to the underside of the board to provide the position feedback to the Arduino.
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Signing UpStep 1: The board
Cut the circular board out of a 1200mm x 1200mm (48” x 48”) sheet of 19mm (¾”) plywood using the attached design (disk.eps). The 3.175mm (1/8”) wide circular slots are cut 6.35mm (¼”) deep to locate the acrylic walls of the maze. I made it at TechShop using the ShopBot and the attached Vcarve file (disk.crv). You could do it manually using a hand-held router and a piece of string.
The outer maze wall is 57.15mm (2¼”) wide strips of 3.175mm (1/8”) thick clear acrylic. These are screwed at regular intervals around the edge of the board with wood screws and washers, and positioned so that the lower edge is flush with the underside of the board. The inner maze walls are 44.45mm (1¾”) wide strips of the same acrylic, so that once they are bedded into the 6.35mm (¼”) deep slots, they are the same height as the outer wall.
The inner two rings of walls have to be softened in an oven before they can be bent enough to fit the tighter radii of the slots. This can be a tricky operation. I placed the acrylic strips (one at a time) on a baking sheet and kept the oven at a low temperature and continually checked so that the acrylic didn’t get too soft. Make sure you’re wearing gloves when you get the acrylic out of the oven.
The walls need to be glued into their slots. Even if they are a snug fit, the banging of the ball eventually pops them out.
The outer maze wall is 57.15mm (2¼”) wide strips of 3.175mm (1/8”) thick clear acrylic. These are screwed at regular intervals around the edge of the board with wood screws and washers, and positioned so that the lower edge is flush with the underside of the board. The inner maze walls are 44.45mm (1¾”) wide strips of the same acrylic, so that once they are bedded into the 6.35mm (¼”) deep slots, they are the same height as the outer wall.
The inner two rings of walls have to be softened in an oven before they can be bent enough to fit the tighter radii of the slots. This can be a tricky operation. I placed the acrylic strips (one at a time) on a baking sheet and kept the oven at a low temperature and continually checked so that the acrylic didn’t get too soft. Make sure you’re wearing gloves when you get the acrylic out of the oven.
The walls need to be glued into their slots. Even if they are a snug fit, the banging of the ball eventually pops them out.
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You would be able to use accelerometers from other devices, but would take a bit of work to extract and determine their characteristics. I don't have any experience of doing so. If you have access to Amazon or Ebay there are some "accelerometer modules" to choose from. I've also attached an Android app that can control it without needing to buy an accelerometer, if you happen to have an Android device.
Can you describe rangefinders system? it isn't clear to me where to mount it and how it works?
I've just added a photo that shows where to place the rangefinders. One points straight down the front-back axis, and the other points parallel to the left-right axis.
Each rangefinder detects how far the player is from it, and sends the distance reading to the Arduino. The system is calibrated with a particular distance from each rangefinder that will result in the platform being flat. Any distance readings on either side of these 'flat' readings will result in the platform tilting proportionately.
I hope this helps, but let me know if you'd like more info.
Cheers, David.
I think about height. Usualy, when playing, kids waving their hands, so it seems to me better place ragefinders on head level. What do you think? How it works for you?
I'd love to try it.