Electrical

The electrical system is composed of two main elements: the electrical hardware and the Arduino firmware used to control the motors and communicate with Python.

The electrical hardware consists of the following:

• 1 Arduino Mega 2560
• 1 Ramps 1.4 Shield
• 5 A4988 Stepper Motor Drivers
• 2 Nema 17 Bipolar Stepper Motors
• 3 Kysan Electronics Bipolar Stepper Motors
• 4 MakerBot Mechanical Limit Switches
• 1 ESV ½” plastic zero differential solenoid valve
• 1 Henxlco 12V 20A Power Supply

Three Axis Gantry Control System

We use the StepperDriver library from the Arduino IDE, as the Arduino provides easy-to-use firmware libraries to control the motor movements. The StepperDriver library contains a MultiDriver library that moves the motors simultaneously. We also use a Ramps 1.4 shield in to connect the stepper motors, where we refer to this linkfor pin connections.

Milk Extrusion

A solenoid valve is used to extrude the milk. The milk is poured from the funnel into a plastic tubing that connects the end of the funnel to the top of the valve. The valve is made of stainless steel, which is food safe. We soldered the valve connections on a board, where it is also connected to a MOSFET transistor and a diode as shown in the schematic below. The valve is connected to PIN17 on the Arduino Mega.

Higher Voltage Power Connection

We bought a 12V, 20A power supply in order to power our system. The e-stop allows a maximum 6A of current to run through the system. We used barrel jack connectors to connect the Ramps 1.4 shield to the e-stop, then another one to connect the e-stop to the power supply. The 3-wire power cord then connects the power supply to the wall plug.