Encoder.h

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#pragma once

#include "mbed.h"

namespace nxpcup {

class Encoder {
public:
    struct Config {
        PinName pin; 
        int pulsePerRevolution = 400; 
        float gearRatio = 78 / 36.0; 
        int wheelCircumference = 204; 
    };

    Encoder(Config config)
        : m_config(config)
        , m_interrupt(config.pin)
    {
        m_interrupt.rise(callback(this, &Encoder::increment));

        // set the PullUp for the encoder pin
        DigitalIn inputPin(config.pin);
        inputPin.mode(PullUp);
    }

    float update(uint16_t timeSinceLastCallUs)
    {
        m_speed = (1000.0 * m_config.wheelCircumference * m_count) / (m_config.pulsePerRevolution * m_config.gearRatio * timeSinceLastCallUs);
        m_distanceCount += m_count;
        m_count = 0;

        return m_speed;
    }

    float speed() const { return m_speed; }

    float distance() const
    {
        float encoderParams = m_config.pulsePerRevolution * m_config.gearRatio * 1000 /* mm => meters */;
        return static_cast<float>(m_config.wheelCircumference * m_distanceCount) / (encoderParams);
    }

    void resetDistance()
    {
        m_distanceCount = 0;
    }

private:
    void increment() { m_count++; }

    Config m_config;
    InterruptIn m_interrupt;
    volatile uint16_t m_count = 0;
    float m_speed = 0;
    long m_distanceCount = 0;
};

} // namespace nxpcup