TeleToyland Rolling Ball Machine - How It Works
For the TeleToyland Rolling Ball Machine (RBM), we started with a Chaos Tower from Chaos World of Motion. It's a great RBM building set with all kinds of gizmos for the balls to run through and bounce off of. Note that our RBM uses about 1/4 of the parts in that kit. We had started with a bigger one, but at the 320x240 video size, you really can't see the balls with a bigger setup.
The ramps were the next challenge. The ramps that come with the kit are great, but are really two state: Each ball sets the state of the ramp as it rolls off. This is perfect for the toy, but we wanted to add an element of web control. If we added servos to those, they would just catch the balls. So, we needed to make our own ramps. To do this, we attached a servo and bracket to a long section of track, and used a short section of track for the ramp.
The control system starts on the web server, where PHP scripts manage the inputs, and then make a connection to the PC that runs the servos. That PC is connected via the serial port to a Pololu Serial 8-Servo Controller, which allows us to set the servo speed to make the ramps not move too quickly. We used trial an error to set the left and right values for each servo.
The servos are Hitec HS-425BB hobby servos from Servo City, but they are carried at many online stores and hobby shops. There isn't anything special about these servos - just a nice combination of features and price.
The light is an LED bulb used as an incandescent replacement - probably around the same lumens as a 50 watt bulb. It's in a regular aluminum shop housing, with a Picoswitch servo controlled relay turning it on and off.