The Shaker Motor Project
Some machines have shaker motors from the factory, some have them as options, and some don't have them at all. I set out to design a board that will allow other machines to run a shaker motor. ST:TNG has been a popular machine for this modification, using the shield flashers to make the machine shake. However, using shield signals directly results in rather weak shakes. Also, the machine shakes the most during attract mode - not so good.
My solution was to build a microcontroller-based controller. Although it is primarily designed for a shaker motor, it can also do flashers, solenoids and other DC devices.
I have some prototypes in hand now. Pinbits will carry them. Depending on demand, we'll do another run.
We also have motor brackets in process. You can get shaker motors, weights, and complete assemblies from Bay Area Amusements.
Here's how we installed the shaker motor.
Here's a picture of the first electronics prototype. It is quite compact :
The design requires 20V flasher power and ground; the motor connector; and the flasher wire. I have it connected to the underside of the playfield with clip leads right now.
The motor is driven by an IRL540N, which is a monster transistor capable of withstanding peak currents of 120A. The microcontroller rapidly pulses the motor to limit the speed. The circuit runs off of the 20V flasher supply without problems.
On the input side, there are two sense inputs. These inputs can be configured to work from flashers, solenoids, the lamp matrix and maybe even switches (requires some tricky coding).
My first target machine is ST:TNG. Here, the microprocessor watches the shield flasher input, and generates timed motor bursts from the shield flashes. It also shuts down if it thinks that the machine is in attract mode.
Shield hit: longer shake (Borg battle, Cardassians)
Advance warp: brief shake
Mr. Data Advises: brief shake
Asteroid hit; wormhole; time rift: brief shakes
Final Frontier: Longer shake, then quiet
Attract mode: Longer shake, then quiet
Safety
The motor is like one that you would find in a largish cordless drill, and can
take a lot of power. It could do some nasty damage to fingers, which is why the
assembly has finger guards. The IRL540N has an integrated snubbing diode, which
will take care of surprise peaks out of the motor (a solenoid will require an
external diode). As it runs off of the flasher voltage, it has a 5A fuse and a
0.1 ohm limiting resistor already in circuit. It does require a 5A slow blow
fuse.
Because the controller is smart, it can limit the motor if, for example, the flasher transistor fails. The microprocessor is diode isolated from the motor, reducing its vulnerability to surprises. And the IRL540N is just tough. If all else fails, there's the flasher fuse in the head to protect it.
The Pinbits Motor
We are working on our own shaker motor. The picture below is a pretty good
representation of what the final assembly will look like.
Wiring a Stern/Williams Motor
Our 4-pin connector is compatible with the Williams/Stern pinout. Pin 3 must be
clipped, and pin 5 hangs off the end. These two pictures show how it works.
The Wiring Harness
Here's a picture of the wiring harness.The board will screw to the cabinet by
the tilt mechanism, and the long wire follows the cabinet harness up into the
head. On ST:TNG, the harness couples into the backboard flashers and the ground
lug. We have some pretty spiffy crimp connectors that will make this about as
clean as it can be, with no soldering required.
