PID library for Arduino with improved accuracy and configurability compared to the legacy Arduino PID library.

PID stands for Proportional, Integral, Derivative, and is a common feedback control strategy. A PID controller continuously calculates an error value as the difference between a desired setpoint and a measured process variable, and applies corrections via three terms:

• P (Proportional): Reacts proportionally to the error.
• I (Integral): Accumulates past errors to eliminate steady-state offset.
• D (Derivative): Predicts future error based on its rate of change to dampen oscillations.

PID controllers can stabilize control for systems such as motors, servos, temperature, or even cruise control in vehicles.

See this explanation video: How PID Controllers Work

A detailed guide can be found here: PID Tuning Guide

#include "ArduPID.h"

ArduPID myController;

float setpoint = 512;
float input;
float output;

float kp = 1.0;
float ki = 0.0;
float kd = 0.0;

void setup()
{
    Serial.begin(115200);

    // Set PID gains
    myController.setTunings(kp, ki, kd);

    // Optional configuration
    myController.setOutputLimits(0, 255);   // Clip output to actuator range
    myController.setILimits(-100, 100);     // Prevent integral wind-up
    myController.setPLimits(-255, 255);     // Optional P term limits
    myController.setDLimits(-50, 50);       // Optional D term limits
    myController.setDirection(ArduPID::FORWARD); // Set output direction
}

void loop()
{
    // Read sensor input
    input = analogRead(A0); // Replace with your sensor reading

    // Compute PID output
    output = myController.compute(input);

    // Debug information (prints selected signals to Serial)
    myController.debug(ArduPID::PRINT_OUTPUT   |
                       ArduPID::PRINT_SETPOINT);

    // Send output to actuator
    analogWrite(3, output); // Replace with your actuator control
}

• setDirection(Direction dir) – Set output direction. Resets PID state if changed.
• setTunings(float kp, float ki, float kd) – Set PID gains (all positive values).
• setOutputLimits(float min, float max) – Clip the PID output to specified range.
• setPLimits(float min, float max) – Limit the proportional term.
• setILimits(float min, float max) – Limit the integral term to prevent wind-up.
• setDLimits(float min, float max) – Limit the derivative term.
• setPMode(PMode mode) – Choose P_ON_E (proportional on error) or P_ON_M (proportional on measurement).
• setDMode(DMode mode) – Choose derivative on error or measurement.
• setAntiWindMode(AntiWindMode mode) – Choose anti-windup strategy: NONE, BACK_CALC, or CLEGG.
• setDtMs(float dt) / setDtUs(uint32_t dt) / setDtS(float dt) – Set sample time. Resets PID state if changed.
• setSetpoint(float sp) – Update target value for PID.
• reset() – Resets internal PID state (P, I, D, errors, timestamps). Useful when changing direction, sample time, or after major system changes.
• debug(uint16_t mask, Stream &stream) – Print selected PID signals to serial for plotting or monitoring.