门磁开合记录器：给 ESP32 做一个可靠的状态输入

// ---- DoorContact.h ----
// SPDX-License-Identifier: MIT
#pragma once
#include <stdint.h>
class DoorContact {
 public:
  enum Event { NONE, INITIAL, OPENED, CLOSED };
  Event update(bool electricalOpen, uint32_t now) {
    if (!started_) { started_=true; candidate_=electricalOpen; changed_=now; }
    if (electricalOpen!=candidate_) { candidate_=electricalOpen; changed_=now; }
    if (uint32_t(now-changed_)<30) return NONE;
    if (!known_) { known_=true; open_=candidate_; since_=now; return INITIAL; }
    if (candidate_==open_) return NONE;
    open_=candidate_; since_=now;
    if(open_) { ++opens_; return OPENED; }
    ++closes_; return CLOSED;
  }
  bool known() const { return known_; }
  bool open() const { return open_; }
  uint32_t opens() const { return opens_; }
  uint32_t closes() const { return closes_; }
  uint32_t age(uint32_t now) const { return known_?uint32_t(now-since_):0; }
 private:
  bool started_=false,known_=false,candidate_=true,open_=true;
  uint32_t changed_=0,since_=0,opens_=0,closes_=0;
};

// ---- esp32-reed-switch-door-state.ino ----
// SPDX-License-Identifier: MIT
// S05: PID375 two-wire dry contact; GPIO5 pull-up, other wire GND.
#include <Arduino.h>
#include "DoorContact.h"
constexpr uint8_t CONTACT_PIN=5, LED_PIN=4;
DoorContact contact;
void setup() {
  pinMode(CONTACT_PIN,INPUT_PULLUP);
  pinMode(LED_PIN,OUTPUT); digitalWrite(LED_PIN,LOW);
  Serial.begin(115200);
  Serial.println("S05 core=3.3.12 PID375 GPIO5; HIGH means electrical open OR broken wire, not a security diagnosis");
}
void loop() {
  static uint32_t reportedAt=0;
  const uint32_t now=millis();
  const auto event=contact.update(digitalRead(CONTACT_PIN)==HIGH,now);
  if(event!=DoorContact::NONE) {
    digitalWrite(LED_PIN,contact.open()?LOW:HIGH);
    Serial.printf("event=%s electrical=%s opens=%lu closes=%lu at=%lu\n",
      event==DoorContact::INITIAL?"INITIAL":event==DoorContact::OPENED?"OPENED":"CLOSED",
      contact.open()?"OPEN":"CLOSED",(unsigned long)contact.opens(),
      (unsigned long)contact.closes(),(unsigned long)now);
  }
  if(uint32_t(now-reportedAt)>=1000) {
    reportedAt=now;
    Serial.printf("state=%s age_ms=%lu opens=%lu closes=%lu; counters reset on reboot\n",
      !contact.known()?"UNKNOWN":contact.open()?"CONTACT_OPEN":"CONTACT_CLOSED",
      (unsigned long)contact.age(now),(unsigned long)contact.opens(),(unsigned long)contact.closes());
  }
  delay(1);
}

clang++ -std=c++17 -Wall -Wextra -Werror tests/contact_test.cpp -o /tmp/s05-contact-test
/tmp/s05-contact-test