3-Wire Devices#

3-Wire devices connect to the three-pin ports on the EXP Brain. These devices include sensors, legacy motors, and actuators that communicate using simple analog or digital signals.

Below is a list of available 3-Wire devices:

  • 3-Wire Expander - A 3-Wire Expander adds additional 3-Wire ports when all of a Brain’s built-in ports are in use.

  • Accelerometer - Detects acceleration and tilt along multiple axes to measure motion and orientation. The sensor includes a jumper that adjusts sensitivity between 2G and 6G ranges.

  • Addressable LED - Controls LED strips from a 3-Wire port, allowing individual LEDs to be set to specific colors and patterns.

  • Analog - Reads a continuous voltage signal from an analog 3-Wire sensor to report values across a range.

  • Bumper Switch - A spring-loaded switch used for detecting collisions or impacts on the robot.

  • Digital In - Reads binary input signals (high or low) from external devices such as switches or sensors.

  • Digital Out - Sends binary output signals (high or low) to control external devices like LEDs or relays.

  • Encoder - Measures the relative rotational position and direction of a shaft to determine speed or distance traveled.

  • Gyro Sensor - The Gyro Sensor measures the heading and the rotation of the robot.

  • LED Indicator - Controls LED Indicators by turning them on or off.

  • Light Sensor - Measures the intensity of ambient light to detect brightness or contrast changes in the robot’s environment.

  • Limit Switch - A small switch that detects contact with objects or surfaces.

  • Line Tracker - Detects differences in light reflection, allowing the robot to follow lines on the field surface.

  • Object Sensor - Uses infrared reflection to detect whether an object is nearby, returning a digital signal when something is within range.

  • Potentiometer - Measures the angular position of a rotating shaft or mechanism. The sensor supports 270 degrees of rotation.

  • Pulse Width Modulation (PWM) - Outputs a pulse-width-modulated control signal through a 3-Wire port to drive legacy motor controllers or servos.

  • Range Finder - Uses ultrasonic sound waves to measure the distance between the sensor and nearby objects.

These devices connect to one of eight 3-Wire ports (a through h) on the EXP Brain or a 3-Wire Expander. When constructing a 3-Wire device, pass the correct port as the port argument:

  • On the EXP Brain, ports are accessed through brain.three_wire_port (for example, brain.three_wire_port.a).

  • On a 3-Wire Expander, ports are accessed directly from the expander instance (for example, expander.a).

# Connect a Gyro Sensor to the Brain's E port
gyro_sensor = Gyro(brain.three_wire_port.e)

# Connect a Line Tracker to the 3-Wire Expander's C port
line_tracker = Line(expander.c)