HardwareMap

The HardwareMap connects your code to the physical devices on your robot.

Before your code can control a motor, servo, or sensor, it must get a reference to that device from the HardwareMap.

Robot Configuration Names

Every piece of hardware on your robot has a configuration name.

Example:

leftMotor
rightMotor
clawServo
imu

Your code must use the exact same name.

Getting Hardware

Hardware is retrieved using:

hardwareMap.get()

The format is:

deviceType variable = hardwareMap.get(deviceType.class, "name");

Example:

DcMotor motor;

motor = hardwareMap.get(DcMotor.class, "leftMotor");

Mapping Variables

Usually, hardware is initialized at the beginning of your OpMode.

@Override
public void runOpMode() {

    DcMotor leftMotor;

    leftMotor = hardwareMap.get(DcMotor.class, "leftMotor");

}

Common Hardware Types

Motors

DcMotor motor;

Servos

Servo servo;

Sensors

DistanceSensor sensor;

Common Errors

Wrong Device Name

Example configuration:

left_drive

Code:

hardwareMap.get(DcMotor.class, "leftMotor");

The names do not match, causing an error.

Missing Hardware

If a device is not connected or configured, initialization will fail.

NullPointerException

A common mistake is using hardware before initializing it.

Bad:

DcMotor motor;

motor.setPower(1);

The motor does not reference anything.

Good:

DcMotor motor;

motor = hardwareMap.get(DcMotor.class, "motor");

motor.setPower(1);

Best Practices

• Use descriptive names.
• Keep configuration names consistent.
• Initialize hardware before using it.
• Avoid changing names during the season.

Key Takeaways

• HardwareMap connects software to hardware.
• Names must exactly match the robot configuration.
• Always initialize hardware before using it.
• Most hardware errors come from incorrect configuration.