Electronic – Mini Skee Ball – Detecting a ping pong ball

capacitorproximity-sensorraspberry pisensor

Background

I really want to do something with my raspberry pi, so I thought of a game that's a mix between skee ball and beer pong. Basically, the build is a mini skee ball board (about 20×24 inches) without the ramp. The player would throw ping pong balls from a distance (like beer pong) and try to make it into the holes. The board would be padded so the balls don't bounce off, but would slide into a hole and down a return ramp that's below the board. I want the holes to sense the ping pong balls, but I don't know the best way of going about doing that (cheaply, too).

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Solutions

This is where I need help. Which way of sensing would be best? Have any other ideas? I thought of:

  1. Distance/Proximity sensor. When the balls go through a hole, they're sent along a path that makes them go through a "lane" of the exit. The proximity sensor would read how far away it is (its "lane") and from that reading I would know which hole it went through.
  2. Cons are that this one is a little complicated, as it requires me to tunnel the balls as they fall down the ramp. I also don't know how much room a sensor would need to detect distances straight in front of it. It would register the ball late, which is not preferred. However, the plus sides are that it requires only one sensor and it wouldn't be prone to shaking the table.

  3. Force-sensitive sensor. Use an analog (converted to digital because raspi) force sensitive resistor under each hole to pick up when a ball hits the area and get which cup it went into.
  4. Cons are that I would need multiple sensors and a D-A converter, the ball might be too light to register, and could be prone to shaking to acquire points. Pros are that it's faster feedback and would be fairly simple to implement.

  5. Capacitive touch. I could by a cheap board (MPR121) that triggers on capacitive touch and somehow get the balls to trigger them.
  6. Cons are that I don't know how to get the balls to trigger them (help pls, ping pong balls are light). Depending on the setup it could be complicated and/or prone to shaking. Pros are that it's cheap and would probably trigger quickly.

I can give more information if needed (crude drawings of plans, etc.) or any other information. I really want to make this a reality so help if you can or input any ideas of your own!

Thanks!

Best Answer

Good luck keeping ping-pong balls from bouncing — they are really good at it!

As far as detection, I would recommend going with infrared emitter-detector pairs, sensing when a ball blocks the path of the light as it passes through a target cup.