Hardware Abstraction for Robotics: Connecting Sensors and Actuators

Introduction

Robots interact with the physical world through hardware.

Sensors provide information such as:

Temperature
Position
Velocity
Distance
Camera images
IMU measurements

Actuators perform physical actions:

Motors
Servos
Grippers
Linear actuators
Valves

Hardware abstraction creates a software layer between robot applications and physical devices.

Why Hardware Abstraction Matters

Without abstraction, application code can become tightly coupled to specific hardware.

For example:

Application
    |
Motor A API
Motor B API
Motor C API

A better architecture is:

Application
    |
Hardware Abstraction Layer
    |
+---+---+---+
|   |   |   |
A   B   C   Motor Drivers

The application works with a common interface rather than knowing the details of each motor controller.

Sensor Interface

A sensor interface might expose:

class TemperatureSensor {
public:
    virtual double readTemperature() = 0;
};

Different hardware implementations can then provide the same interface.

class I2CTemperatureSensor : public TemperatureSensor {
public:
    double readTemperature() override {
        // Read sensor over I2C
        return 25.0;
    }
};

The application only needs to know that it can call:

sensor.readTemperature();

Actuator Interface

A similar abstraction can be created for motors:

class Motor {
public:
    virtual void setVelocity(double velocity) = 0;
    virtual double getPosition() = 0;
};

Different motor drivers can implement this interface.

Hardware Communication

Common robot hardware interfaces include:

I2C
SPI
UART
CAN
USB
Ethernet
GPIO

The hardware abstraction layer hides protocol-specific details from higher-level software.

Example Architecture

                 Robot Application
                        |
              Hardware Abstraction
                        |
        +---------------+---------------+
        |               |               |
      Camera           IMU            Motor
        |               |               |
      USB              SPI             CAN

This architecture makes hardware replacement easier.

Error Handling

Hardware abstraction should also standardize failures.

For example:

enum class SensorStatus {
    OK,
    TIMEOUT,
    DISCONNECTED,
    INVALID_DATA
};

A higher-level application can then respond consistently regardless of the underlying sensor.

Simulation

A major advantage of abstraction is that the same interface can be implemented using simulated hardware.

Application
     |
Hardware Interface
   /       \
Real      Simulation
Hardware    Model

This enables development and testing before physical hardware is available.

Best Practices

Keep hardware-specific code at the lowest layer.
Use stable interfaces.
Standardize error handling.
Include timestamps with sensor data.
Validate sensor ranges.
Make hardware drivers independently testable.
Provide simulation implementations when possible.

Conclusion

Hardware abstraction makes robotic systems easier to maintain, test, simulate, and extend. It allows Physical AI software to focus on behavior and decisions while lower-level components handle the details of communicating with physical devices.