The Tower
The tower is the core of our system and holds the majority of sensors and components. Its primary job is to rotate smoothly and accurately so that the beer nozzles may track and fill the cups without any spills. It does this with a 60RPM DC geared motor, a hall sensor, and two ping sensors. The hall sensor will pick up when the turntable is in position by sensing magnets embedded in the wood. The ping sensors then detect if empty cups are in front of the nozzles and, if so, the dc motor begins to track the cups. |
Baseplate
The tower base-plate connects the tower motor and several sensors to the central brass tube. Two ping sensors are mounted and aimed such that they are able to detect the presence of empty cups. Coupled with a hall sensor affixed to the edge of the base-plate, the tower is able to find cup holder locations accurately, double check that empty cups are present, and fill or skip them depending on the sensor readings. |
Brass Tube
The centerpiece of our machine is the brass tube which routes the beer lines along with power and sensor wires.
In order to attach the tube to the machine and allow it to spin, custom bearing fixtures were created. The inner face of these bearings slide over a rigid inner tube that is fixed to the base of the machine with a pipe flange. |
Brainbox
Our brainbox houses an Arduino Mega which controls all the sensors and motors. A relay board was used for the high-current solenoids and three h-bridge chips were used to control the motors. The servo was driven directly from the Arduino.
The components were affixed with wood screws directly into the box. A hollow area can be seen that mimics the profile of the pinch valves. This area is used for discreetly housing quick-connect cables and excess lengths of wire as well as the beer lines themselves. |
shuttle
The shuttle lowers stainless steel beer filling tubes to the bottom of the cups to minimize the foam produced while filling. On the underside of the shuttle are two ‘ping’ sensors that measure how full the cups are. Once the cup has filled, the sensors send a signal to the brain causing the valves to close and the shuttle/nozzles to retract. The shuttle rides on three precision rails with linear ball bearings which provide a smooth operation and reduced friction. The middle rail is hollowed out providing a clean and hidden cable route for the sensors on the bottom of the tower. |
pinch Valves
The dual valve uses the principles of a pinch valve to limit the flow of beer. It works well for the purpose of dispensing beer because it is a non-contact valve that uses solenoids to compress the beer lines, which in turn, minimizes foam and simplifies the cleaning process. The valve uses spring force to compress the beer lines, therefore preventing the beer from escaping in the case of a power outage. These valves are normally closed with zero input from the brain, which minimizes the amount of time heat is produced. Housed inside the valve mount is also the shuttle driving motor. |