Alternate Solution Number One

The first potential idea for my solution would be to have the soft serve attachment retrieve its power from the actual soft serve ice cream machine. It would be integrated into the system and there would be no need to worry about a source of external power. We would use this power to make our attachment vibrate, which would result in the success of our project. The ice cream machine receives power from an outlet in the wall, which is receiving power from transformers. We would tap into this power supply and would convert the energy into vibration.
The electricity that the ice cream machine receives is used for a variety of tasks within the actual machine. The majority of the power goes into the refrigeration system. The refrigeration system is obviously what keeps the ice cream cold and what keeps it from spoiling. There is a coolant that lies within the machine. This coolant is heated, which results in a loss of temperature in the rest of the machine. It is this loss of temperature that allows the ice cream to stay cold. The electricity is needed to heat the coolant, and since this such an integral part of the ice cream system, I feel like it would be safer to not tap into the power source here.
The next thing that the electricity is used for is pushing the ice cream into the tubes. The back wall of the ice cream machine is made so that it can move back and forth. There is a piston that lies behind this wall and it pushes the wall inward, thus forcing the ice cream to leave the system. The wires that allow this transaction to take place are lying at the bottom half of the machine. These wires can be easily accessed, and it would not be very difficult to tap into the power supply. I feel like this is the optimal line to use to power our device. We would need to split the wire, and allow half of the energy to come into our attachment. This energy would be more than sufficient to power the vibrations our machine needs.
The power supply would be made available at the same location as the ice cream is being poured. It would be available in the form of a two pronged plug, with our attachment having the socket built into it. This would power tiny pistons to collide with the sides of our attachment. This collision would create vibrations that echoed throughout the machine. These vibrations would cause movement for the sprinkles, thus freeing them from their compartments. Then they would slide down the curved bottom of the attachment, and penetrate the ice cream.

This solution is extremely viable in terms of being efficient. The main problem would be the practacality. For store owners to use our product, they would then need to significantly alter their machines, risking breaking them or hurting themselves. This is a big setback, but some might think it would be worth having unlimited power. The machine would be extremely efficient undoubtedly, but it still remains to be seen whether or not it is the best option available.

The image above is of the electrical circuit diagram and how the 

soft serve attachment would be integrated into the system.