This page provides definitions for common terms used in the Smoothieware documentation.
Alternating Current
In AC, the electric current periodically reverses direction and changes its magnitude continuously with time. This creates a sinusoidal waveform.
AC is the type of electricity delivered through wall sockets in homes and businesses. It is used because it can be easily transformed to different voltages for efficient long-distance transmission. Most PSUs convert AC from the wall to DC for use by electronics like Smoothieboard.
An axis represents a direction of movement in a machine. Most machines have three axes: X (left-right), Y (front-back), and Z (up-down). Some machines have additional axes for features like tool rotation or multiple extruders.
See the motion control documentation for configuration options.
The speed at which data is transmitted over a serial connection, measured in bits per second. Common baud rates for Smoothieboard communication include 115200 and 250000. The baud rate must match between the board and the host software for communication to work.
See the USB documentation for more details.
The flat surface on which parts are built or machined. In 3D printers, the bed is often heated to help prints adhere and reduce warping. In CNC mills, the bed holds the workpiece. In laser cutters, the bed supports the material being cut or engraved.
See MOSFETs.
Computer-Aided Manufacturing Software
Software that converts designs (from CAD software) into machine instructions (G-code). Examples include Simplify3D for 3D printing, Fusion 360 for CNC milling, and LaserWeb for laser cutting.
See the software page for a list of compatible CAM applications.
Protective housings for electronics like Smoothieboard. Cases protect the board from dust, debris, and accidental contact. They also provide mounting points and can help with heat dissipation. Cases can be 3D printed, laser cut from acrylic, or purchased ready-made.
Computer Numerical Control
CNC refers to the automated control of machining tools by means of a computer. CNC machines read G-code instructions and precisely control motors to move tools or workpieces. Smoothieware supports various CNC applications including 3D printers, laser cutters, CNC mills, and pick-and-place machines.
Current is the flow of electric charge (electrons) through a conductor, measured in Amperes (Amps or A). In the context of Smoothieboard, current settings are important for stepper motors - too little current and the motor won’t have enough torque; too much current can overheat and damage the motor.
See the current control documentation for configuration.
Direct Current
In DC, electric current flows in only one direction, maintaining a constant polarity. Batteries produce DC power, and most electronics (including Smoothieboard) operate on DC. A PSU converts AC from the wall outlet into the DC voltage required by the board (typically 12V or 24V).
A type of 3D printer or robot with three arms connected to a moving platform. Delta printers use trigonometric calculations to convert Cartesian coordinates into arm movements. They can achieve very fast print speeds but require careful calibration.
See the delta guide for setup instructions.
An endstop is a sensor (usually a mechanical switch or optical sensor) placed at the end of an axis to detect when the moving parts reach their limit. Smoothieboard has 6 endstop inputs: two for each of the three primary axes (min and max positions).
Endstops serve two main purposes:
See the endstops documentation for wiring and configuration.
A networking standard for wired local area networks. Smoothieboard includes an Ethernet port for network connectivity, allowing you to control the machine over a local network, access the web interface, and transfer files.
See the network documentation for setup instructions.
The component of a 3D printer that pushes filament into the hotend to be melted and deposited. An extruder typically consists of a motor, drive gear, and idler that grip and push the filament.
Some printers have multiple extruders for multi-color or multi-material printing. See the extruder documentation and multiple extruders guide.
The software that runs directly on Smoothieboard, interpreting G-code commands and controlling the hardware. Smoothieware is the firmware, and it can be updated by copying a new firmware.bin file to the SD card.
See flashing the firmware for update instructions.
The process of updating the firmware on Smoothieboard. To flash new firmware:
firmware.bin file from the firmware pageFIRMWARE.CUR after successful flashing)See the flashing guide for detailed instructions.
G-code is the programming language used to control CNC machines. It consists of commands that tell the machine where to move, how fast, and what actions to perform (like heating, extruding, or firing a laser).
Examples:
G0 X10 Y20 - Rapid move to position X=10, Y=20G1 F1000 E10 - Extrude 10mm of filament at 1000mm/minM104 S200 - Set hotend temperature to 200°CSee the supported G-codes documentation for a complete reference.
GitHub is a web-based platform for version control and collaboration. The Smoothieware project uses GitHub to host its source code, track issues, and manage contributions from the community.
See the GitHub guide for how to contribute.
General Purpose Input/Output
GPIO pins on Smoothieboard can be configured as either inputs (to read signals) or outputs (to control devices). They are used for various purposes including endstops, switches, fans, and custom sensors.
See the pinout and pin configuration documentation for available pins and how to use them.
A type of sensor that detects magnetic fields. Hall effect sensors are used in some endstop implementations where a magnet on the moving carriage triggers the sensor. They are contactless, meaning they don’t wear out like mechanical switches, and can be very precise.
A build platform that can be heated, commonly used in 3D printers. Heating the bed helps prints adhere better and reduces warping, especially with materials like ABS. Smoothieboard can control heated beds through its big MOSFETs.
See the temperature control documentation for configuration.
Homing is the process of moving each axis until it triggers an endstop, establishing a known reference position (usually called “home” or “origin”). Before printing or machining, homing ensures the machine knows its exact position.
The G28 command triggers homing. See the G28 documentation for details.
Software running on a computer that communicates with Smoothieboard to send commands and monitor status. Examples include:
See the software page for a complete list.
The component of a 3D printer that melts filament for extrusion. A hotend typically consists of:
See the extruder documentation for configuration.
A switch used to define the boundaries of machine movement. While similar to endstops, the term “limit switch” often specifically refers to using endstop switches as safety limits to prevent the machine from crashing into mechanical stops.
See the endstops documentation for wiring and configuration.
The ARM Cortex-M3 microcontroller used in Smoothieboard V1. This 32-bit microcontroller runs at 120MHz and provides the processing power for interpreting G-code, controlling stepper motors, and managing all board peripherals. The LPC1769 has extensive GPIO capabilities and built-in peripherals including USB, Ethernet, and PWM controllers.
See the LPC1769 pin usage documentation for detailed pin mapping.
In Smoothieware, a module is a self-contained piece of code that handles a specific function. Examples include the extruder module, laser module, spindle module, and temperature control module.
Modules can be enabled or disabled through the configuration file. See the module development guide for creating custom modules.
Metal-Oxide-Semiconductor Field-Effect Transistors
MOSFETs are electronic switches used on Smoothieboard to control high-current devices. Smoothieboard has two types:
These are controlled via PWM for variable power output or simple on/off switching.
NC = Normally Closed and NO = Normally Open
These terms describe the default state of a switch:
See the endstops documentation for configuration of NC and NO switches.
The small opening at the end of a hotend through which molten filament is extruded. Nozzles come in various diameters (0.2mm to 1.0mm are common), with 0.4mm being standard. Smaller nozzles produce finer detail but slower prints; larger nozzles print faster but with less detail.
A simple switch for controlling power to the machine or specific components. Can be used with the Switch module to control devices via G-code or GPIO pins.
An LCD display with buttons or encoder for controlling Smoothieboard without a computer. Panels allow you to start prints from the SD card, adjust settings, and monitor status.
Smoothieboard supports various panel types including RepRap Discount panels and custom SmoothiePanel designs. See the panel documentation for supported models and configuration.
Proportional-Integral-Derivative
A control algorithm used to maintain temperature stability in hotends and heated beds. PID tuning adjusts how aggressively the heater responds to temperature differences:
See the PID tuning guide for automatic tuning.
The mapping of functions to specific pins on Smoothieboard. Understanding the pinout is essential for wiring endstops, motors, heaters, and other peripherals.
See the pinout documentation and LPC1769 pin usage for detailed pin maps.
Electrical power is measured in Watts (W) and equals voltage multiplied by current (P = V x I). Understanding power requirements is important for:
See the getting started guide for power requirements.
A popular open-source host software for controlling 3D printers. Pronterface provides a graphical interface for sending G-code, monitoring temperatures, and manually controlling the machine.
See the Pronterface documentation for setup and usage.
Power Supply Unit
A device that converts mains AC power to low-voltage DC for electronics. Smoothieboard typically requires 12V or 24V DC power.
Common PSU types:
Choose a PSU with sufficient wattage for your stepper motors, heaters, and other loads.
Resistors used to ensure a GPIO pin has a defined logic state when not actively driven:
Smoothieboard has internal pullup resistors that can be enabled in the pin configuration. These are commonly used with endstop switches.
Pulse Width Modulation
A technique for controlling power by rapidly switching a device on and off. The ratio of on-time to off-time (duty cycle) determines the effective power delivered. PWM is used to control:
See the PWM-capable pins documentation for which pins support PWM.
Resistance is opposition to the flow of electric current, measured in Ohms. In the context of Smoothieware, resistance values are important for thermistors (temperature sensors) which change resistance with temperature.
See the thermistor choice guide for selecting and configuring thermistors.
Smoothieboard uses an SD card for storing configuration files, G-code files, and the firmware. The SD card acts as the board’s filesystem.
Key files on the SD card:
config.txt or config - Configuration filefirmware.bin - New firmware (renamed after flashing)See the SD card documentation for formatting and usage.
A device that detects physical properties and converts them to electrical signals. Common sensors in CNC applications include:
See the sensor types documentation for configuration options.
See MOSFETs.
A rotating tool holder used in CNC mills and routers. Unlike a stationary laser or hotend, spindles rotate cutting tools at high speeds to remove material. Smoothieware can control spindle speed via PWM or RS485.
See the spindle module documentation for configuration.
A type of motor that moves in discrete steps, allowing precise position control without feedback sensors. Smoothieboard can control up to 5 stepper motors (or more with external drivers).
Each step moves the motor a fixed angle (typically 1.8 degrees or 0.9 degrees). Microstepping divides these steps further for smoother motion.
See the stepper motor documentation for wiring and configuration.
The dual-core ARM Cortex-M7/M4 microcontroller used in Smoothieboard V2. This advanced microcontroller features a 480MHz Cortex-M7 core for high-performance processing and a 240MHz Cortex-M4 core for secondary tasks. The STM32H745 provides significantly more processing power than the LPC1769, enabling advanced features, faster G-code processing, and smoother motion control.
See the Smoothieboard V2 documentation for board-specific information.
A temperature sensor that changes resistance with temperature. Thermistors are commonly used to measure hotend and heated bed temperatures. Different thermistor types have different resistance curves, so the correct type must be configured in Smoothieware.
See the thermistor choice guide and sensor types for configuration.
An advanced stepper motor driver used in Smoothieboard V2. The TMC2590 is a high-performance driver that supports up to 1/256 microstepping for exceptionally smooth and quiet motor operation. It features current control, thermal protection, stall detection, and diagnostics capabilities. The TMC2590’s advanced features enable quieter operation and more precise motion control compared to the TMC2660 used in V1.
See the stepper motor documentation for driver configuration.
A stepper motor driver used in Smoothieboard V1. The TMC2660 supports up to 1/32 microstepping and provides current control for smooth motor operation. It includes features like stallGuard (stall detection) and coolStep (energy-efficient operation). The TMC2660 enables quiet operation and precise motion control for stepper motors.
See the stepper motor documentation for driver configuration.
Universal Serial Bus
A standard for connecting computers to peripherals. Smoothieboard appears as a serial device when connected via USB, allowing host software to communicate with the board.
See the USB documentation for drivers and troubleshooting.
Voltage Bus for Big (high-power) devices
The main power input on Smoothieboard that supplies stepper motors and high-power outputs. VBB typically accepts 12-24V DC from a PSU. The voltage you choose affects motor torque, speed, and heater performance.
See the Smoothieboard documentation for power input specifications.
Voltage is the electrical potential difference between two points, measured in Volts (V). It can be thought of as the “pressure” pushing current through a circuit. Common voltages in Smoothieboard setups:
A sensor used to measure the distance between the tool (typically a nozzle) and the bed. Z-probes enable automatic bed leveling and mesh compensation, improving print quality on uneven surfaces.
Types of Z-probes:
See the Z-probe documentation for wiring and configuration.