Team Churro: Sharon Grimshaw, Maggie Su, Louis Yi, and Morgan Zheng

Project Goals Safe Heat: no burns Moving components: no pinching Easy Loading: one container, easily removed, to fill Cooking: machine removes when done User choice Length or number of churros Shape of churro

The Website

Initial Idea

Mechanical Subsystem Extruder Cutter/Shaper Stirrer Lifter Shaker

Mechanical Subsystem – Lifter Pulley System Rack and Pinion Vertical lifting Can lift more weight Can still use 1 motor to control movements of 2 sets of pulleys Vertical lifting Too much load on gear/motor, assuming initial idea of lifting stirrer and mesh grid assembly. Use 1 motor to lift all Gear & racks may be expensive Initial Idea: Need to lift an assembly consisting of a stirring mechanism with a platform and a mesh grid. Revised Idea: Only lifting mesh grid, but need to constrain vertical motion

Mechanical Subsystem - Extruder How to keep the threaded rod vertical? Guide hole Fixed to the motor Will we have enough torque? Stepper motor instead of servo Gears

Mechanical Subsystem - Structure Stability through weight Stability through attachment Make supports heavier so that pieces don’t move Overall smaller system Difficult to move around (multiple heavy pieces) Attach supports (L brackets) to base and frames so they do not move Easier to transport because only one piece Easier to set up because distance between pieces is predefined Large, bulky system

Electrical Subsystem - Overview To be powered on 12 volts 2 stepper motors 3 servo Temperature gauge Thermocouple Instrumentation amplifier Character LCD display

Electrical Subsystem – Stepper Control Basic H-bridge driver: Requires four input pins to control each motor Revised two-pin control: Uses transistors to set polarity across coils – two input pins per stepper

Software Component Motor control – Arduino Stepper/Servo Libraries Stirrer/Shaker can run on a loop Extruder, cutter, and lifter relies on user input GUI Python Serial communication is relatively easy to deal with Lots of GUI libraries to choose from – some of which are painful to deal with Processing Theoretically very good for Arduino GUIs Requires generic firmware that communicates with a Processing Library – may interfere with the use of other Arduino libraries.

Where we’re going…

Questions? Comments? Concerns?