The special theme at BrickFair Virginia this year was Fire. I have always wanted to build a pinball machine, so I figured the LEGO NXT would be a good platform. This is what I came up with

Turned out OK, but served more a lesson for version 2.

Some Statistics:

1. I have no idea how many bricks it uses. I purchased a 10197 Fire Brigade set, a case of RED 2x4 bricks and 5 to 6 PAB cups worth of parts. I also got a 4208 4x4 Fire Truck for extra tree parts at the last minute.
   
2. It used 3 NXT bricks, 7 touch sensors, 6 motors, 3 lights, and 1 light sensor
   
3. It used some of the Mindsensors flex cables, and one of their Digital Port Spliters
   
4. Other than the Mindsensors parts, the only non-LEGO part was the ball. I used the ball from an old computer mouse.
   
5. The NXT bricks are connected on Port4 to the Digital Port Splitter. They use R485 for communication.
   
6. It was programmed in RobotC. All three programs total slightly over 700 lines if memory serves.
   

I had some fun and made my own font for the NXT. (It was based on a free Truetype flaming font)

Here is a pic from under the playfield

The controls for the machine were on three 1.5 meter long cables. This let me hand the controls to the public without letting anyone touch the machine. The front NXT took the flipper and ball-launch buttons, and controlled the Ball-launch and flipper motors. The Left NXT at the top controlled the game state. It took ALL inputs, managed the 2 play-field motors, and the ball-return motor. It detected the ball had drained using a light sensor. It then used some lift-arms to place it on the shooter lane. Every-time the ball drained, or a something was scored it sent out a 1 character message on the RS485 bus, and the other 2 NXTs reacted as needed. The last NXT was mainly used for displaying 2 score digits. It also managed the lights on the center target

You scored points by lighting the three center lights. You could also make the house in the upper left spin if you hit the left switch. If you hit the tree, the NXT motor saw the movement, and spun to act kinda as a pop bumper. (Both the spinner and the 3 light target were based on the NXT pinball built at the university of Windsor)

Lessons Learned: (In case anyone else tries their hand at pinball)

This was my first large MOC. I learned several important lessons.

1. These things take time. I started this about 10-12 days before the convention. I had to commit at that point to get the table space and MOC card. I had done some very limited testing but way under-estimated how long it would take to finish. I had to take some time off of work to finish, and it consumed 100% of my free time. I was forced to bring the machine to BrickFair in a VERY unfinished state. So I had to spend most of the convention working like a mad-man to get it done before the public hours. I missed all of the talks I wanted to attend.
   
2. I wanted powered flippers. This allowed me to put the controls on a remote control. I also had to work out an automatic ball launcher. Both worked OK, but not great
   
3. I made it 30 inches deep so it would fit on a table. But that was really too small for the size ball I used. The game ended up simpler than I wanted.
   
4. Most Mindstorms pinball machines do not include a backglass area. Therefore most tilt the whole frame by using short lets in the front. This makes attaching the backglass very hard. A normal pinball has 4 of the same size legs, and tilts the playfield using internal rails. This makes the connection between the main cabinet and the backglass square and stable. This should also make designing a folding mechanism much easier.
   
5. While I though the mouse ball would help keep the bricks from getting dents, I forgot the rubber coating is slightly sticky. This left a slight trail of rubber, and slowed the machine down over the course of the weekend.
   
6. I forgot to leave room for something to take the ball from the shooting lane to the main playfield. I had a triangle, but it did not work well. It required constant adjustment to keep the ball from draining right after launch.
   

Clearly I wanted more on the backglass, and the programming could use some more work. That will have to wait for a rebuild to version 2.

Andrew Page

This was a great MOC at Brickfair. When I first saw it, I did not see the kid with the controllers and I thought you had programed it with sensors to flip the pinball on its own.

Great work and I cannot wait to see version 2.

This was a great MOC at Brickfair. When I first saw it, I did not see the kid with the controllers and I thought you had programed it with sensors to flip the pinball on its own.

Great work and I cannot wait to see version 2.

Would not be that difficult. You could even put some self-learning to "aim" The same sensor could be used for scoring the in-lanes. It would make a good demo, and give me a chance to run to the bathroom during public hours.