Ball Game

I finished the first iteration of a Plinko-like ball game I started working on a while ago for my son. It uses printed parts, some plywood, a sheet of Lexan, and a Nerf Rival ball to create a simple combination of pinball and the famous Plinko game from The Price is Right.

The objective isn’t well defined, but the boys enjoy playing with it. A friend suggested replacing some of the peg openings with cups that correspond to score amounts to provide an objective for the player to work toward. I may do that in the next iteration.

Sorry about the video quality–I can’t find my better camera at the moment.

Inside cuts

I cut out the slot for the reloading handle to travel in tonight. This handle will rotate the ball-catching tray (this needs a better name) up from near-horizontal to vertical, at which point the player will slide it up to the top, Sliding it up to the top will run all of the balls back into the magazine to prepare for another round of play.

I did this by cutting 1/4″ holes on either end of the slot, removing the blade from the scroll saw, putting the blade through one of the holes, then reattaching the blade to the saw.

Anyway, here’s a picture:

Getting my bearings

I made a few key improvements to the bearing launcher/gun tonight:

  • Added a ramp to guide the balls to the front of the launcher
  • Switched to a slightly (1/32″) larger brass tube
  • Filed a groove into the trigger for the rubber band to rest in

These changes dramatically increased the reliability of the launcher. I recorded a couple videos, one just showing the new features and another showing a “fast as you can pull the trigger” speed test.



Ok, I’m taking a little break from the steam engine project. After getting the piston and valve made, it became apparent the precision I’m capable of with my Dremel and drill press are not sufficient for the rigors of rapid cyclic motion (as suspected from the start).

While I think more about that, I am working on a wooden arcade game that challenges the player to drop or launch .50 ball bearings down a slope to hit targets. The game will be fully enclosed (to prevent removal of the ball bearings) and will feature a pistol-grip ball launcher/gun as the input mechanism.

Below is a video demonstration of the prototype launcher. The brass receiver tube (the internal magazine) is so closely matched to the .50 balls they occasionally jam in there, so I’m looking into remedies for that. But you can see how the device drops out one ball while retaining the others until the player releases and pulls the trigger again. Ultimately, a supply of balls from within the game itself will replenish that brass tube as the player launches balls, since the tube only holds four.

I’ll post more details about how this works if the project looks ultimately feasible.

A soft interlude

At the start of the winter, I set a goal for myself to create a simple PC game I could play in the living room on my Steam Link with my son. Winter wears on, and I’ve been so focused on the motor and other hardware projects, I really haven’t done much with this goal.

Today I set aside the motor project (which is waiting on the 4mm parts from England) and worked a bunch on the game.

The game will be like Space Invaders or Galaga, but you shoot at the invading aliens from stationary positions, like Missile Command. The aliens’ goal is to descend and abduct citizens, who run in hapless panic back and forth across the bottom of the screen. Ideally you kill the aliens before they abduct anyone, but if someone does get picked up, you can safely rescue them by deploying a Sky Commando. Sky Commandos swoop in with wingsuits from the nearest side of the screen, and if you aim their arc correctly, they’ll grab onto the alien ship and attack it from within, destroying it and rescuing any abductees. Sky Commandos are a limited but reusable resource, which just means you can only have a finite number of them in play at a time.

The game is meant to be played with a gamepad since I intend to play it in the living room. I’ll release it for free if it shapes up into something worth releasing.

Today’s progress was implementing the alien AI that allows them to identify and move in on a potential abductee. Otherwise, I have the game engine in place (using the entity/component/system, or ECS, model) with an observer pattern to inform systems about entities they should care about or stop caring about. I’m implementing it all in C# using MonoGame. Currently the player can shoot at aliens with a rapid-fire weapon, and as I said, aliens will now pick a citizen to abduct and descend to get them.