As its name implies, the SCLM’s main function is to brew Chai Tea with minimal user input. From a high-level perspective, the user simply fills up both the water and milk containers, checks to ensure a sufficient quantity of tea and masala in the solids dispensers, specifies the desired number of servings, and presses the “ON” button. To go into more detail, the final design consists of five major components: solids dispensers, liquid dispensers, a stirrer, an induction cooktop, and electronics. An important distinction to highlight is that the final SCLM prototype does not provide a physical interface (i.e. a switch, knob, or slider) with which the user can specify his desired serving size. Due to time constraints with the project, serving sizes are specified by adjusting parameters in the microprocessor’s code. The following is an overview of the functions of each component:
Solids Dispenser: The solid dispensing mechanism is what dispenses the proper amount of tea leaves and masala during the tea-making process. It is also removable so that it may be cleaned occasionally. Its functional requirements are to measure and deploy proper amounts of tea leaves and masala in the pot. The dispensed ingredients are dropped onto a funnel and guided into the carafe using a fluid-flush assist from the liquid dispensing system.
Liquid Dispenser: This component dispenses the appropriate amount of water and milk into the pot. Two separate liquid dispensers are used for the milk and the water. Both these liquid dispensers are identical in form and function and consist of three components: a docking base, a liquid container, and a quick-disconnect valve for easy removal. By being easy to remove, the milk container can be removed from its base after each usage and placed in the refrigerator to prevent spoiling of the milk. This removability feature also enables convenient cleaning of the milk tubing system. By removing the milk container from its base and replacing it with the water container, the milk system can then pump water through its tubes, thereby cleaning out the milk. This component’s functional requirement is to measure and dispense the proper amount of water and milk in the pot along with assisting the insertion of solids by fluid flush. A subcomponent of the liquids dispensing system is the tubing assembly. This tubing system’s purpose is to transport liquids from their containers and into the carafe. It consists of tubing, pumps, flow meters, and optional valves.
Stirrer: The stirrer mechanism is integrated in the lid and serves to ensure that all the ingredients are distributed and brewed evenly throughout the mixture instead of being stuck to the sides of the pot. This stirrer also helps to delay the onset of frothing. By continually disturbing and breaking the protein-lipid layer that forms from evaporating water from milk, the stirrer ensures that a brew can be cooked for a significantly greater quantity of time following the insertion of milk. A gear mounted to the pot’s lid interfaces with a motor mounted to the machine’s frame. Its functional requirement is to ensure that all ingredients are mixed into the drink properly when brewing as well as to help prevent frothing. .
Induction Heating Unit: The Chai Latte machine uses an off-the-shelf induction cooktop to boil the brew. The pot used is constructed of a ferromagnetic stainless steel that is compatible with induction heating. This material composition allows for extremely rapid heating through excitations of electric currents (Eddy currents) within the stainless steel material. The heating unit’s functional requirement is to boil the water and milk as fast as possible.
Electronics: The Chai Latte machine’s electronic system serves as the control unit of the SCLM. At the heart of the electronics system is an Arduino Uno microprocessor. The processor receives the user input and accordingly controls the solids dispensers’ motors and the liquid dispensers’ pumps. Moreover, it monitors the temperature of the brew in real-time, controls the induction cooktop accordingly, and ultimately manages the entire Chai-making process. Its functional requirement is to control the machine depending on what stage of brewing the tea is in.
Assembly: The overall assembly of these components is accomplished through the usage of aluminum T-slot extrusions. These extrusions constitute the SCLM’s frame. Acrylic sheets serve as material for the SCLM’s flooring, side panels, and various other fixtures within the machine interior. The final result is a fully functioning Chai Tea machine with an extremely modular internal layout.