为什么 PIR 传感器在 nodeMCU/ESP8266 板上保持高电平？

Question

我有一个 PIR 传感器连接到 Amica nodeMCU 板，从 VIN 路由 5v，并通过 USB 端口连接以进行测试。当检测到运动时，它会连接到互联网并将数据发送到 IFTTT，我在 phone.

上收到通知

当我通电时，PIR 暂停进行校准，然后立即变为高电平并触发我在 phone 上收到的运动检测呼叫。然而从那时起，它永远不会变低，但即使没有运动，每 5-8 分钟也会发送另一个高信号。

测试

尝试对 PIR 使用单独的 5v 电源，同样的事情发生了
我已经尝试了两种重新触发模式（H 和 L）并且得到了相同的结果
Adafruit featherwing huzzah 板也是如此。
我已经在没有微控制器的情况下测试了 PIR，可以确认它功能正常 -点亮 LED
我已经用相同代码使用 Arduino Nano 进行了测试，它 功能正常 - 点亮 LED

的修改版本

//Sends IFTTT every 5 minutes it detects motion

#include <ESP8266WiFi.h>
//WiFi Settings

// Set up macros for wifi and connection.
#define SSID "my-network"    // SSID
#define PASS "mypassphrase"      // Network Password
#define HOST "maker.ifttt.com"  // Webhost
//-------------------------------
const char* streamId   = "test";
const char* privateKey = "mysecretkey";

//PIR Settings
//the time we give the sensor to calibrate (10-60 secs according to the datasheet)
int calibrationTime = 10;        

//the time when the sensor outputs a low impulse
long unsigned int lowIn;         

//the amount of milliseconds the sensor has to be low 
//before we assume all motion has stopped
long unsigned int pause = 5000;  


int  interval = 1000; // Wait between dumps
boolean lockLow = true;
boolean takeLowTime;  
int ledPin = 1;
int pirPin = 2;    //the digital pin connected to the PIR sensor's output
int nPIR_detect;
int motion = 2;

int minSecsBetweenUpdates = 300; // 5 minutes
long lastSend = -minSecsBetweenUpdates * 1000l;
//-------------------------------

// Begin Setup
void setup(){
  Serial.begin(115200);
  pinMode(pirPin, INPUT);
  digitalWrite(pirPin, LOW);

  //give the sensor some time to calibrate
  Serial.print("calibrating sensor ");
  for(int i = 0; i < calibrationTime; i++){
    Serial.print(".");
    delay(1000);
    }
  Serial.println(" done");
  Serial.println("SENSOR ACTIVE");
  delay(50);
   nPIR_detect = 0;  

  // Test ESP8266 module.
  Serial.println("AT");
  delay(5000);
  if(Serial.find("OK")){
    connectWiFi();
  }
}

void loop(){
 if(digitalRead(pirPin) == HIGH){
       digitalWrite(BUILTIN_LED, HIGH);   //the led visualizes the sensors output pin state
       if(lockLow){  
         //makes sure we wait for a transition to LOW before any further output is made:
         lockLow = false;            
         Serial.println("---");
         Serial.print("motion detected at ");
         Serial.print(millis()/1000);
         Serial.println(" sec"); 
         sendData(String(motion));
         delay(50);
         }         
         takeLowTime = true;
       }

     if(digitalRead(pirPin) == LOW){       
       digitalWrite(BUILTIN_LED, LOW);  //the led visualizes the sensors output pin state

       if(takeLowTime){
        lowIn = millis();          //save the time of the transition from high to LOW
        takeLowTime = false;       //make sure this is only done at the start of a LOW phase
        }
       //if the sensor is low for more than the given pause, 
       //we assume that no more motion is going to happen
       if(!lockLow && millis() - lowIn > pause){  
           //makes sure this block of code is only executed again after 
           //a new motion sequence has been detected
           lockLow = true;                        
           Serial.print("motion ended at ");      //output
           Serial.print((millis() - pause)/1000);
           Serial.println(" sec");
           delay(50);
           }
       }
}

void sendData(String motion){

  //Send the motion to IFTTT value1
  Serial.print("connecting to ");
  Serial.println(HOST);

  // Use WiFiClient class to create TCP connections
  WiFiClient client;
  const int httpPort = 80;
  if (!client.connect(HOST, httpPort)) {
    Serial.println("connection failed");
    return;
  }

  // We now create a URI for the request
  String url = "/trigger/";
  url += streamId;
  url += "/with/key/";
  url += privateKey;
  url += "?value1=";
  url += "motion";

  Serial.print("Requesting URL: ");
  Serial.println(url);

  // This will send the request to the server
  client.print(String("GET ") + url + " HTTP/1.1\r\n" +
               "Host: " + HOST + "\r\n" + 
               "Connection: close\r\n\r\n");
  delay(10);

  // Read all the lines of the reply from server and print them to Serial
  while(client.available()){
    String line = client.readStringUntil('\r');
    Serial.print(line);
  }

  Serial.println();
  Serial.println("closing connection");

}

boolean connectWiFi(){
  Serial.println("AT+CWMODE=1");
  delay(2000);
  String cmd="AT+CWJAP=\"";
  cmd+=SSID;
  cmd+="\",\"";
  cmd+=PASS;
  cmd+="\"";
  Serial.println(cmd);
  delay(5000);
  if(Serial.find("OK")){
    Serial.println("Connection");
    return true;
  }
  else{
    Serial.println("No Connection");
    return false;
  }
}

为什么 nodeMCU/ESP8266 板的 PIR 传感器保持高电平？

本质上，我从来没有看到串口消息"motion ended at.."

Answer 1

几个月后，但希望能帮助其他遇到同样问题的人。我沮丧了数周并尝试了几个 PIR 模块，结果相同（令人沮丧），我发现问题是由我在 nodeMCU 开发板中刷新固件的方式引起的。

我有 ESP-12E，正在使用以下命令上传固件：

esptool.py --port /dev/cu.SLAB_USBtoUART --baud 115200 write_flash -fm dio -fs 32m 0x00000 /Users/dev/nodemcu-firmware.bin

问题是 -fm dio（双闪光 I/O 模式）参数。一些 ESP8266 模块，包括一些（不是所有）NodeMCU 板上的 ESP-12E 模块，是双 I/O 并且固件只有在使用 --flash_mode dio[=20= 闪烁时才会启动] 或 -fm dio 但就我而言，这是我所有头痛的根源。一旦我在没有该选项的情况下刷新固件，一切都开始像魅力一样工作。

Answer 2

通过插入 V_in 的节点 MCU 和 V_cc 的 PIR 就可以解决问题。似乎 PIR 需要 ~5V，只有 V_in 可以提供那种电压。早些时候，当插入 3.3v 时，我每隔 x 秒就会得到一系列高电平。

为什么 PIR 传感器在 nodeMCU/ESP8266 板上保持高电平？

Why does PIR sensor stay high with nodeMCU/ESP8266 board?

arduino

esp8266

ifttt