リアルタイムデータを活用したスマート信号機制御システム

ソースコード

Arduino送信側スケッチ

/* IOTOPIA - 2016-2017 - Traffic Light Information System (Transmitter)
 * by Pieter Luyten & Joppe Smeets
 * RF 433MHzモジュールで距離データを別Arduinoへ送信
 * RF tx_pin -> pin 3
 * HC-SR04: trig_pin -> pin 5, echo_pin -> pin 6
 */
#define tx_pin 3
#define trig_pin 5
#define echo_pin 6
#include <VirtualWire.h>
#include "HCSR04.h"
HCSR04 ultrasonic(trig_pin, echo_pin);
int distance;
char CharMsg[21];

void setup() {
  Serial.begin(9600);
  vw_setup(2000);
  vw_set_tx_pin(tx_pin);
}

void loop() {
  distance = ultrasonic.Ranging(CM);
  while(distance < 0) distance = ultrasonic.Ranging(CM);
  sprintf(CharMsg, "%d,", distance);
  vw_send((uint8_t *)CharMsg, strlen(CharMsg));
  vw_wait_tx();
  Serial.print("Distance (cm): ");
  Serial.println(distance);
  delay(250);
}

Arduino受信側スケッチ（Yun用・MySQL連携）

/* IOTOPIA - 2016-2017 - Traffic Light Information System (Receiver + MySQL)
 * by Pieter Luyten & Joppe Smeets
 * RF受信・信号機制御・MySQLアップロード
 * RF rx_pin -> pin 9 (注: コメントと実装でpin番号が異なるため要確認)
 * LED: Red=5, Orange=6, Green=7
 * DS3231: SCL=pin3, SDA=pin2 (Yun)
 * SDカード: Yun内蔵スロット
 */
#define RedLED 5
#define OrangeLED 6
#define GreenLED 7
#define rx_pin 9
#include <VirtualWire.h>
#include <TimeAlarms.h>
#include <Wire.h>
#include "RTClib.h"
#include <Process.h>

long UnixTime_green_1, UnixTime_red_1, UnixTime_green_2, UnixTime_red_2;
long s_till_orange;
RTC_DS3231 rtc;
char StringReceived[22];
boolean i;
int interval = 5;
int distance;

void setup() {
  rtc.begin();
  Serial.begin(9600);
  Bridge.begin();
  vw_setup(2000);
  vw_set_rx_pin(rx_pin);
  vw_rx_start();
  Alarm.timerRepeat(interval, UpdateTrafficLData);
  Alarm.timerRepeat(1, PrintCurrentTime);
  pinMode(GreenLED, OUTPUT);
  pinMode(OrangeLED, OUTPUT);
  pinMode(RedLED, OUTPUT);
  digitalWrite(GreenLED, LOW);
  digitalWrite(OrangeLED, LOW);
  digitalWrite(RedLED, LOW);
  Serial.println("Setup finished");
}

void loop() {
  Alarm.delay(0);
  RF_Listen();
}

void RF_Listen() {
  uint8_t buf[VW_MAX_MESSAGE_LEN];
  uint8_t buflen = VW_MAX_MESSAGE_LEN;
  if (vw_get_message(buf, &buflen)) {
    for (int a = 0; a < buflen; a++) StringReceived[a] = char(buf[a]);
    sscanf(StringReceived, "%d", &distance);
    MySQL_UpdateDistance();
    Serial.print("Distance: "); Serial.println(distance);
  }
  memset(StringReceived, 0, sizeof(StringReceived));
}

void UpdateTrafficLData() {
  DateTime now = rtc.now();
  if (i == 1) {
    UnixTime_green_1 = now.unixtime() + interval + 1;
    UnixTime_red_1 = now.unixtime() + 2 * interval + 1;
    UnixTime_green_2 = now.unixtime() + 3 * interval + 1;
    UnixTime_red_2 = now.unixtime() + 4 * interval + 1;
    MySQL_UpdateTrafficLData(); i = 0;
  } else {
    UnixTime_red_1 = now.unixtime() + interval + 1;
    UnixTime_green_1 = now.unixtime() + 2 * interval + 1;
    UnixTime_red_2 = now.unixtime() + 3 * interval + 1;
    UnixTime_green_2 = now.unixtime() + 4 * interval + 1;
    MySQL_UpdateTrafficLData(); i = 1;
  }
  Serial.print(" Green_1 at "); Serial.print(UnixTime_green_1);
  Serial.print(" Red_1 at "); Serial.print(UnixTime_red_1);
  Serial.print(" Green_2 at "); Serial.print(UnixTime_green_2);
  Serial.print(" Red_2 at "); Serial.println(UnixTime_red_2);
}

void MySQL_UpdateTrafficLData() {
  long dataArray[4] = {UnixTime_green_1, UnixTime_red_1, UnixTime_green_2, UnixTime_red_2};
  Process p;
  p.begin("/mnt/sda1/MySQL_UpdateTrafficLData.php");
  for (int b = 0; b < 4; b++) p.addParameter(String(dataArray[b]));
  p.run();
  while (p.available() > 0) Serial.print(p.read());
  Serial.flush();
}

void MySQL_UpdateDistance() {
  Process p;
  p.begin("/mnt/sda1/MySQL_UpdateDistance.php");
  p.addParameter(String(distance));
  p.run();
  while (p.available() > 0) Serial.print(p.read());
  Serial.flush();
}

void PrintCurrentTime() {
  DateTime now = rtc.now();
  SetLEDsTrafficL();
  Serial.print(now.hour()); Serial.print(':');
  Serial.print(now.minute()); Serial.print(':');
  Serial.print(now.second()); Serial.print(' ');
  Serial.println(now.unixtime());
}

void SetLEDsTrafficL() {
  DateTime now = rtc.now();
  s_till_orange = UnixTime_red_1 - now.unixtime();
  if (i == 0) { digitalWrite(GreenLED, LOW); digitalWrite(OrangeLED, LOW); digitalWrite(RedLED, HIGH); }
  if (i == 1 && s_till_orange <= 3) { digitalWrite(GreenLED, LOW); digitalWrite(OrangeLED, HIGH); digitalWrite(RedLED, LOW); }
  if (i == 1 && s_till_orange > 3) { digitalWrite(GreenLED, HIGH); digitalWrite(OrangeLED, LOW); digitalWrite(RedLED, LOW); }
}

MySQL_UpdateTrafficLData.php (SDカード上で実行)

#!/usr/bin/php-cli
<?php
$UnixTime_green_1 = $argv[1];
$UnixTime_red_1 = $argv[2];
$UnixTime_green_2 = $argv[3];
$UnixTime_red_2 = $argv[4];
$DBServer = 'yourServerName';
$DBUser = 'yourUserName';
$DBPass = 'yourPassword';
$DBName = 'yourDBName';
$conn = new mysqli($DBServer, $DBUser, $DBPass, $DBName);
if ($conn->connect_error) trigger_error('DB connection failed: ' . $conn->connect_error, E_USER_ERROR);
$sql = "UPDATE TrafficL_data SET UnixTime_green_1='$UnixTime_green_1', UnixTime_red_1='$UnixTime_red_1', UnixTime_green_2='$UnixTime_green_2', UnixTime_red_2='$UnixTime_red_2' WHERE id=1";
if ($conn->query($sql) === false) trigger_error('Wrong SQL: ' . $sql . ' Error: ' . $conn->error, E_USER_ERROR);
else echo "Data inserted!\n";
?>

MySQL_UpdateDistance.php

#!/usr/bin/php-cli
<?php
$Distance = $argv[1];
$DBServer = 'yourServerName';
$DBUser = 'yourUserName';
$DBPass = 'yourPassword';
$DBName = 'yourDBName';
$conn = new mysqli($DBServer, $DBUser, $DBPass, $DBName);
if ($conn->connect_error) trigger_error('DB connection failed: ' . $conn->connect_error, E_USER_ERROR);
$sql = "UPDATE TrafficL_data SET Distance='$Distance' WHERE id=1";
if ($conn->query($sql) === false) trigger_error('Wrong SQL: ' . $sql . ' Error: ' . $conn->error, E_USER_ERROR);
else echo "Distance inserted!\n";
?>

EchoJSON.php (Androidアプリ用JSON出力)

<?php
define('HOST', 'yourServerName');
define('USER', 'yourUserName');
define('PASS', 'yourPassword');
define('DB', 'yourDBName');
$con = mysqli_connect(HOST, USER, PASS, DB);
$sql = "select * from TrafficL_data";
$res = mysqli_query($con, $sql);
while($row = mysqli_fetch_array($res, MYSQLI_BOTH)){
  printf('[ { "TrafficLArray": [ { "UnixTime_green_1":"%s", "UnixTime_red_1":"%s", "UnixTime_green_2":"%s", "UnixTime_red_2":"%s", "Distance":"%s" } ] } ]',
    $row['UnixTime_green_1'], $row['UnixTime_red_1'], $row['UnixTime_green_2'], $row['UnixTime_red_2'], $row['Distance']);
}
mysqli_close($con);
?>

MainActivity.java (Androidアプリメインロジック)

package com.example.xxx.xxx; // パッケージ名を変更
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.Date;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class MainActivity extends AppCompatActivity {
  TextView results, recSpeed;
  String JsonURL = "YourURLhere";
  RequestQueue requestQueue;
  private final static double maxSpeed = 18; // cm/s
  private double speed;
  public final static int NUMBER_OF_ENTRIES = 2;
  long[] unixTimesGreen = new long[NUMBER_OF_ENTRIES];
  long[] unixTimesRed = new long[NUMBER_OF_ENTRIES];
  private double distance;
  private final ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();
  private Future<?> timingTask;

  public void tick(long milliseconds) {
    timingTask = scheduler.scheduleAtFixedRate(() -> updateTable(), 0, milliseconds, TimeUnit.MILLISECONDS);
  }

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    results = findViewById(R.id.jsonData);
    recSpeed = findViewById(R.id.recommendedSpeed);
    updateTable();
    tick(500);
  }

  private void updateTable() {
    requestQueue = Volley.newRequestQueue(this);
    JsonArrayRequest arrayreq = new JsonArrayRequest(JsonURL,
      response -> {
        try {
          JSONObject TrafficLObj = response.getJSONObject(0);
          JSONArray trafficArry = TrafficLObj.getJSONArray("TrafficLArray");
          for (int i = 0; i < trafficArry.length(); i++) {
            JSONObject jsonObject = trafficArry.getJSONObject(i);
            String[] green = new String[NUMBER_OF_ENTRIES];
            String[] red = new String[NUMBER_OF_ENTRIES];
            String distanceTemp = jsonObject.getString("Distance");
            distance = (double) Long.parseLong(distanceTemp);
            green[0] = jsonObject.getString("UnixTime_green_1");
            red[0] = jsonObject.getString("UnixTime_red_1");
            green[1] = jsonObject.getString("UnixTime_green_2");
            red[1] = jsonObject.getString("UnixTime_red_2");
            for (int j = 0; j < unixTimesRed.length; j++) {
              unixTimesGreen[j] = Long.parseLong(green[j]);
              unixTimesRed[j] = Long.parseLong(red[j]);
            }
          }
          updateTextView();
        } catch (JSONException e) { e.printStackTrace(); }
      },
      error -> Log.e("Volley", "Error")
    );
    requestQueue.add(arrayreq);
  }

  private void updateTextView() {
    StringBuilder builder = new StringBuilder();
    for (int i = 0; i < unixTimesGreen.length; i++) {
      builder.append("unixTimeGreen").append(i).append(": ").append(new Date(unixTimesGreen[i]*1000)).append("\n");
      builder.append("unixTimeRed").append(i).append(": ").append(new Date(unixTimesRed[i]*1000)).append("\n");
    }
    builder.append("distance: ").append(distance);
    speedCalc();
    recSpeed.setText(String.format("%.0f", speed));
  }

  private void speedCalc() {
    int interval = 0;
    double time = System.currentTimeMillis() / 1000.0;
    for (int i = 0; i < NUMBER_OF_ENTRIES; i++) {
      double diff = unixTimesRed[interval] - time;
      speed = distance / (diff / 1000);
      interval++;
    }
    interval--;
    if (distance / (unixTimesGreen[interval] - time) > maxSpeed) speed = maxSpeed;
    else speed = distance / (unixTimesGreen[interval] - time);
    speed *= 5; // 表示用スケーリング
  }
}

AndroidManifest.xml / strings.xml / activity_main.xml

プロジェクトページのコードセクションを参照してください。strings.xml のアプリ名は「NooitRood」（オランダ語で「Never Red＝赤信号なし」の意）です。

回路図

送信側 (Arduino UNO + HC-SR04 + 433MHz送信機)

• 433MHz tx_pin → pin 3
• HC-SR04 trig_pin → pin 5, echo_pin → pin 6

受信側 (Arduino Yun + 433MHz受信機 + LED信号機 + DS3231)

• 433MHz rx_pin → pin 9
• LED: Red→pin5, Orange→pin6, Green→pin7
• DS3231: SCL→pin3, SDA→pin2 (Yun)