オゾン(O3)脱臭器を使っているが、オゾン臭がしているときは濃度が高すぎないか気になり、オゾン臭がしないときは機能しているのかはっきりしない。

おおよそのオゾンの濃度を調べてみたいと思ったので、測定器やセンサーを少し調べてみた。Aliexpress で３千円台でデジタル出力のセンサーモジュールが買えることがわかったので、それを使って M5Stack で試してみることにした。

オゾンセンサーモジュール　ZE27-O3

Zhengzhou Winsen Electronics Technology Co., Ltd (炜盛科技)のセンサーモジュール　ZE27-O3 を購入した。ヘッダピンを取り付けられるようになっているbreakout board である。

https://www.winsen-sensor.com/sensors/o3-gas-sensor/ze27-o3.html

UART 3V-TTL出力が可能で、ppb 単位の出力が得られる。仕様上は10ppmまで 0.01ppmの分解能ということである。厳密な値が知りたいのではなく、オゾン臭がしている時との大小関係ががわかれば良いので、これで良いとした。

ZE27以外に、ケーブルコネクタがついている ZE25-O3 もあったが、基板の大きさがZE27-O3の方が小さかったので、ZE27-O3を選んだ。しかし、よく仕様をみておらず、ZE27-O3のピンヘッダが2.0mmピッチであることにモジュールが手元に届いてから気がついた。

M5Stackのプロトタイプボードに2.54mm間隔のピンソケットをつけて装着するつもりであったができない。しかたがないので、2.0mmピッチと 2.54mmピッチの変換基板を使うことにした。

2.0mmピッチと 2.54mmピッチの変換基板は、マルツの「XBeeピッチ変換基板ソケットセット」を流用することにした。ZE27-O3は５ピンしか使わないので、XBeeピッチ変換基板の片側の5ピン分だけを利用した。変換基板は、ZE27-O3にはちょっと大きすぎるが、M5Stackのプロトタイプ基板に載る大きさなのでそのまま使うことにした。

使用した部品等

M5Stack Gray
M5Stack Base26 Proto Industrial Board Module
- 2.0mmピッチと 2.54mmピッチの変換基板が必要になったこともあり、Base 15では高さが不足して収まらない。
- Base26 にもプロトタイプボードが含まれているのでそれを使えば次の PROTO Boardは不要。
M5Stack プロトタイプ基板 PROTO Board – DIY Pegboard for Prototyping Development
XBeeピッチ変換基板ソケットセット
Ozone Sensor Module ZE27-O3
2.0mmピッチヘッダピン (ZE27-O3用5本)

組み立て

ピンの対応

ZE27-O3	M5Stack-Gray
pin 1 – Vin	5v
pin 2 – TXD	GPIO16 – RXD2
pin 3 – RXD	GPIO17 – TXD2
pin 4 – GND	GND
pin 5 – NC

基板

基板の緑面(1枚目)の灰色と黄色の配線は実際には使っていない(つながっていない)。配線できなかったので、基板の白面(２枚目)でGNDと16番pinを接続している。

M5Stack Gray と Proto Boardと Base26

動作確認プログラム

https://github.com/fega/winsen-ze03-arduino-library　と https://github.com/m5stack/M5Stack/blob/master/examples/Advanced/Display/TFT_Terminal/TFT_Terminal.ino を基にプログラムを作成した。

開発ツールには、PlatformIO IDE for VSCode　を利用した。

WinsenZE03Example.ino

/*
  WinsenZE03.h - This library allows you to set and read the ZE03 Winsen Sensor module.
	More information: https://github.com/fega/winsen-ze03-arduino-library
  Created by Fabian Gutierrez <fega.hg@gmail.com>, March 17, 2017.
  MIT.
*/
/*
  This file is based on https://github.com/fega/winsen-ze03-arduino-library
  modified by epi on 2021/Feb/17
  for ozone (O3) sensor ZE27-O3
*/

#include <WinsenZE03.h>
#include <M5Stack.h>
#include <Wire.h>

extern void termInit(const char *title);
extern void termPutchar(char data);
extern void termPrintString(const char *str);

WinsenZE03 sensor;

#define INTERVAL 5 * 1000

void setup()
{
  bool LCDenable = true, SDEnable = false, SerialEnable = true, I2CEnable = false;
  M5.begin(LCDenable, SDEnable, SerialEnable, I2CEnable);
  Serial.begin(115200);

  termInit("ZE27-O3");

  Serial2.begin(9600);
  sensor.begin(&Serial2, O3);
  sensor.setAs(QA);
}

unsigned long lastTime;

void loop()
{
  unsigned long now = millis();

  if (M5.BtnA.wasPressed() || now > lastTime + INTERVAL)
  {
    int startupTime = now / 1000;

    lastTime = now;
    float ppm = sensor.readManual();

    // O3 value to string
    char ppmBuf[32];
    dtostrf(ppm, 5, 3, ppmBuf);

    // compose output message
    char lineBuf[128];
    sprintf(lineBuf, "O3: %s ppm,  at %d", ppmBuf, startupTime);
    Serial.printf("%s\n", lineBuf);

    termPrintString(lineBuf);
    termPutchar('\r');
  }
  M5.update();
}

WinsenZE03.h - This library allows you to set and read the ZE03 Winsen Sensor module.

More information: https://github.com/fega/winsen-ze03-arduino-library

Created by Fabian Gutierrez <fega.hg@gmail.com>, March 17, 2017.

MIT.

This file is based on https://github.com/fega/winsen-ze03-arduino-library

modified by epi on 2021/Feb/17

for ozone (O3) sensor ZE27-O3

#include <WinsenZE03.h>

#include <M5Stack.h>

#include <Wire.h>

extern void termInit(const char *title);

extern void termPutchar(char data);

extern void termPrintString(const char *str);

WinsenZE03 sensor;

#define INTERVAL 5 * 1000

void setup()

{

bool LCDenable = true, SDEnable = false, SerialEnable = true, I2CEnable = false;

M5.begin(LCDenable, SDEnable, SerialEnable, I2CEnable);

Serial.begin(115200);

termInit("ZE27-O3");

Serial2.begin(9600);

sensor.begin(&Serial2, O3);

sensor.setAs(QA);

}

unsigned long lastTime;

void loop()

{

unsigned long now = millis();

if (M5.BtnA.wasPressed() || now > lastTime + INTERVAL)

{

int startupTime = now / 1000;

lastTime = now;

float ppm = sensor.readManual();

// O3 value to string

char ppmBuf[32];

dtostrf(ppm, 5, 3, ppmBuf);

// compose output message

char lineBuf[128];

sprintf(lineBuf, "O3: %s ppm, at %d", ppmBuf, startupTime);

Serial.printf("%s\n", lineBuf);

termPrintString(lineBuf);

termPutchar('\r');

}

M5.update();

}

WinsenZE03.h

/*
  Morse.h - This library allows you to set and read the ZE03 Winsen Sensor module.
  Created by Fabian Gutierrez, March 12, 20017.
  MIT.
*/
/*
  This file is based on https://github.com/fega/winsen-ze03-arduino-library
  modified by epi on 2021/Feb/17
  for ozone (O3) sensor ZE27-O3
*/

#ifndef WinsenZE03_h
#define WinsenZE03_h

#include "Arduino.h"
#define CO 1
#define SO2 2
#define NO2 2
#define O2 2
#define NH3 1
#define H2S 1
#define HF 1
#define CL2 2
#define O3 2

#define QA false
#define ACTIVE true

class WinsenZE03
{
  public:
    WinsenZE03();
    void begin(Stream *ser, int type);
    void setAs(bool active);

    float readManual();
#if 0 /* epi 2021/Feb/17 */
    float readContinuous();
#endif
  private:
    void debugPrint(byte arr[]);
    Stream *_s; //Serial1 - Serial3 are USARTClass objects.
    int _type;
};

#endif

Morse.h - This library allows you to set and read the ZE03 Winsen Sensor module.

Created by Fabian Gutierrez, March 12, 20017.

MIT.

This file is based on https://github.com/fega/winsen-ze03-arduino-library

modified by epi on 2021/Feb/17

for ozone (O3) sensor ZE27-O3

#ifndef WinsenZE03_h

#define WinsenZE03_h

#include "Arduino.h"

#define CO 1

#define SO2 2

#define NO2 2

#define O2 2

#define NH3 1

#define H2S 1

#define HF 1

#define CL2 2

#define O3 2

#define QA false

#define ACTIVE true

class WinsenZE03

{

public:

WinsenZE03();

void begin(Stream *ser, int type);

void setAs(bool active);

float readManual();

#if 0 /* epi 2021/Feb/17 */

float readContinuous();

#endif

private:

void debugPrint(byte arr[]);

Stream *_s; //Serial1 - Serial3 are USARTClass objects.

int _type;

};

#endif

WinsenZE03.cpp

/*
  WinsenZE03.h - This library allows you to set and read the ZE03 Winsen Sensor module.
  Created by Fabian Gutierrez, March 12, 2017.
  MIT.
*/
/*
  This file is based on https://github.com/fega/winsen-ze03-arduino-library
  modified by epi on 2021/Feb/17
  for ozone (O3) sensor ZE27-O3
*/

#include "Arduino.h"
#include "WinsenZE03.h"
#define DEVMODE true //Set as true to debug

WinsenZE03::WinsenZE03()
{
  _s = NULL;
}

void WinsenZE03::begin(Stream *ser, int type)
{
  _s = ser;
  _type = type;
}

void WinsenZE03::setAs(bool active)
{
  byte setConfig[] = {0xFF, 0x01, 0x78, 0x41, 0x00, 0x00, 0x00, 0x00, 0x46}; //QA config
  byte response[9] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

  if (active)
  {
    setConfig[3] = 0x40;
    setConfig[8] = 0x47;
  }
  _s->write(setConfig, sizeof(setConfig));
  // Wait for the response
  delay(2000);
  //Flush the incomming buffer
  if (_s->available() > 0)
  {
    _s->readBytes(response, 9);
  }
  while (_s->available() > 0)
  {
    byte c = _s->read();
  }
}

#if 0 /* epi 2021/Feb/17 */
float WinsenZE03::readContinuous()
{
  if (_s->available() > 0)
  {
    byte measure[8];
    _s->readBytes(measure, 9);
    float ppm = 0.001 * (measure[4] * 256 + measure[5]);
    return ppm;
  }
}
#endif

float WinsenZE03::readManual()
{
  float ppm;
  byte petition[] = {0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79}; // Petition to get a single result
  byte measure[8] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};       // Space for the response
  _s->write(petition, sizeof(petition));
  delay(1500);
  // read
  if (_s->available() > 0)
  {
    _s->readBytes(measure, 9);
  }
  // calculate
  if (measure[0] == 0xff && measure[1] == 0x86)
  {
    ppm = 0.001 * (measure[2] * 256 + measure[3]); // this formula depends of the sensor is in the dataSheet
  }
  else
  {
    ppm = -1;
  }
  return ppm;
}

void WinsenZE03::debugPrint(byte arr[])
{
  Serial.print(arr[0], HEX);
  Serial.print(" ");
  Serial.print(arr[1], HEX);
  Serial.print(" ");
  Serial.print(arr[2], HEX);
  Serial.print(" ");
  Serial.print(arr[3], HEX);
  Serial.print(" ");
  Serial.print(arr[4], HEX);
  Serial.print(" ");
  Serial.print(arr[5], HEX);
  Serial.print(" ");
  Serial.print(arr[6], HEX);
  Serial.print(" ");
  Serial.print(arr[7], HEX);
  Serial.print(" ");
  Serial.println(arr[8], HEX);
}

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WinsenZE03.h - This library allows you to set and read the ZE03 Winsen Sensor module.

Created by Fabian Gutierrez, March 12, 2017.

MIT.

This file is based on https://github.com/fega/winsen-ze03-arduino-library

modified by epi on 2021/Feb/17

for ozone (O3) sensor ZE27-O3

#include "Arduino.h"

#include "WinsenZE03.h"

#define DEVMODE true //Set as true to debug

WinsenZE03::WinsenZE03()

{

_s = NULL;

}

void WinsenZE03::begin(Stream *ser, int type)

{

_s = ser;

_type = type;

}

void WinsenZE03::setAs(bool active)

{

byte setConfig[] = {0xFF, 0x01, 0x78, 0x41, 0x00, 0x00, 0x00, 0x00, 0x46}; //QA config

byte response[9] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

if (active)

{

setConfig[3] = 0x40;

setConfig[8] = 0x47;

}

_s->write(setConfig, sizeof(setConfig));

// Wait for the response

delay(2000);

//Flush the incomming buffer

if (_s->available() > 0)

{

_s->readBytes(response, 9);

}

while (_s->available() > 0)

{

byte c = _s->read();

}

#if 0 /* epi 2021/Feb/17 */

float WinsenZE03::readContinuous()

{

if (_s->available() > 0)

{

byte measure[8];

_s->readBytes(measure, 9);

float ppm = 0.001 * (measure[4] * 256 + measure[5]);

return ppm;

}

#endif

float WinsenZE03::readManual()

{

float ppm;

byte petition[] = {0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79}; // Petition to get a single result

byte measure[8] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; // Space for the response

_s->write(petition, sizeof(petition));

delay(1500);

// read

if (_s->available() > 0)

{

_s->readBytes(measure, 9);

}

// calculate

if (measure[0] == 0xff && measure[1] == 0x86)

{

ppm = 0.001 * (measure[2] * 256 + measure[3]); // this formula depends of the sensor is in the dataSheet

}

else

{

ppm = -1;

}

return ppm;

}

void WinsenZE03::debugPrint(byte arr[])

{

Serial.print(arr[0], HEX);

Serial.print(" ");

Serial.print(arr[1], HEX);

Serial.print(" ");

Serial.print(arr[2], HEX);

Serial.print(" ");

Serial.print(arr[3], HEX);

Serial.print(" ");

Serial.print(arr[4], HEX);

Serial.print(" ");

Serial.print(arr[5], HEX);

Serial.print(" ");

Serial.print(arr[6], HEX);

Serial.print(" ");

Serial.print(arr[7], HEX);

Serial.print(" ");

Serial.println(arr[8], HEX);

}

TFT_Terminal.cpp

/*************************************************************
  This sketch implements a simple serial receive terminal
  program for monitoring serial debug messages from another
  board.
  
  Connect GND to target board GND
  Connect RX line to TX line of target board
  Make sure the target and terminal have the same baud rate
  and serial stettings!

  The sketch works with the ILI9341 TFT 240x320 display and
  the called up libraries.
  
  The sketch uses the hardware scrolling feature of the
  display. Modification of this sketch may lead to problems
  unless the ILI9341 data sheet has been understood!

  Updated by Bodmer 21/12/16 for TFT_eSPI library:
  https://github.com/Bodmer/TFT_eSPI
  
  BSD license applies, all text above must be included in any
  redistribution
 *************************************************************/
/*
This file is based on
https://github.com/m5stack/M5Stack/blob/master/examples/Advanced/Display/TFT_Terminal/TFT_Terminal.ino

This file is modified by epi
*/

#include <M5Stack.h>

// The scrolling area must be a integral multiple of TEXT_HEIGHT
#define TEXT_HEIGHT 24    // Height of text to be printed and scrolled
#define TOP_FIXED_AREA 24 // Number of lines in top fixed area (lines counted from top of screen)
#define BOT_FIXED_AREA 0  // Number of lines in bottom fixed area (lines counted from bottom of screen)
#define YMAX 240          // Bottom of screen area
#define XMAX 320

// The initial y coordinate of the top of the scrolling area
uint16_t yStart = TOP_FIXED_AREA;
// yArea must be a integral multiple of TEXT_HEIGHT
uint16_t yArea = YMAX - TOP_FIXED_AREA - BOT_FIXED_AREA;
// The initial y coordinate of the top of the bottom text line
uint16_t yDraw = YMAX - BOT_FIXED_AREA - TEXT_HEIGHT;
//uint16_t yDraw = 0;

// Keep track of the drawing x coordinate
uint16_t xPos = 0;

// For the byte we read from the serial port
byte data = 0;

// A few test variables used during debugging
boolean change_colour = 1;
boolean selected = 1;

// font type
// 1: 8 pixel ASCII
// 2: 16 pixel ASCII
// 4: 24 pixel ASCII
uint16_t fontType = 4;

// We have to blank the top line each time the display is scrolled, but this takes up to 13 milliseconds
// for a full width line, meanwhile the serial buffer may be filling... and overflowing
// We can speed up scrolling of short text lines by just blanking the character we drew
//int blank[19]; // We keep all the strings pixel lengths to optimise the speed of the top line blanking

// ##############################################################################################
// Setup the vertical scrolling start address pointer
// ##############################################################################################
void scrollAddress(uint16_t vsp)
{
  M5.Lcd.writecommand(ILI9341_VSCRSADD); // Vertical scrolling pointer
  M5.Lcd.writedata(vsp >> 8);
  M5.Lcd.writedata(vsp);
}

// ##############################################################################################
// Call this function to scroll the display one text line
// ##############################################################################################
int scroll_line()
{
  int yTemp = yStart; // Store the old yStart, this is where we draw the next line
  // Use the record of line lengths to optimise the rectangle size we need to erase the top line
  // M5.Lcd.fillRect(0,yStart,blank[(yStart-TOP_FIXED_AREA)/TEXT_HEIGHT],TEXT_HEIGHT, TFT_BLACK);
  M5.Lcd.fillRect(0, yStart, XMAX, TEXT_HEIGHT, TFT_BLACK);

  // Change the top of the scroll area
  yStart += TEXT_HEIGHT;
  // The value must wrap around as the screen memory is a circular buffer
  if (yStart >= YMAX - BOT_FIXED_AREA)
    yStart = TOP_FIXED_AREA + (yStart - YMAX + BOT_FIXED_AREA);
  //if (yStart >= YMAX) yStart = 0;
  // Now we can scroll the display
  scrollAddress(yStart);
  return yTemp;
}

// ##############################################################################################
// Setup a portion of the screen for vertical scrolling
// ##############################################################################################
// We are using a hardware feature of the display, so we can only scroll in portrait orientation
void setupScrollArea(uint16_t tfa, uint16_t bfa)
{
  M5.Lcd.writecommand(ILI9341_VSCRDEF); // Vertical scroll definition
  M5.Lcd.writedata(tfa >> 8);           // Top Fixed Area line count
  M5.Lcd.writedata(tfa);
  M5.Lcd.writedata((YMAX - tfa - bfa) >> 8); // Vertical Scrolling Area line count
  M5.Lcd.writedata(YMAX - tfa - bfa);
  M5.Lcd.writedata(bfa >> 8); // Bottom Fixed Area line count
  M5.Lcd.writedata(bfa);
}

void termPutchar(char data)
{
  // while (Serial.available())
  {
    // data = Serial.read();
    // If it is a CR or we are near end of line then scroll one line
    if (data == '\r' || xPos > 311)
    {
      xPos = 0;
      yDraw = scroll_line(); // It can take 13ms to scroll and blank 16 pixel lines
    }
    if (data > 31 && data < 128)
    {
      xPos += M5.Lcd.drawChar(data, xPos, yDraw, fontType);
      //blank[(18+(yStart-TOP_FIXED_AREA)/textHeight)%19]=xPos; // Keep a record of line lengths
    }
    //change_colour = 1; // Line to indicate buffer is being emptied
  }
}

void termPrintString(const char *str)
{
  while (*str)
    termPutchar(*str++);
}

void termInit(const char *title)
{
  // Setup the TFT display
  // M5.Lcd.setRotation(5); // Must be setRotation(0) for this sketch to work correctly
  M5.Lcd.fillScreen(TFT_BLACK);

  M5.Lcd.setTextColor(TFT_WHITE, TFT_BLUE);
  M5.Lcd.fillRect(0, 0, XMAX, TEXT_HEIGHT, TFT_BLUE);
  M5.Lcd.drawCentreString(title, XMAX / 2, 0, fontType);

  // Change colour for scrolling zone text
  M5.Lcd.setTextColor(TFT_WHITE, TFT_BLACK);

  // Setup scroll area
  setupScrollArea(TOP_FIXED_AREA, BOT_FIXED_AREA);
  //setupScrollArea(0, 0);

  // Zero the array
  //for (byte i = 0; i<18; i++) blank[i]=0;
}

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/*************************************************************

This sketch implements a simple serial receive terminal

program for monitoring serial debug messages from another

board.

Connect GND to target board GND

Connect RX line to TX line of target board

Make sure the target and terminal have the same baud rate

and serial stettings!

The sketch works with the ILI9341 TFT 240x320 display and

the called up libraries.

The sketch uses the hardware scrolling feature of the

display. Modification of this sketch may lead to problems

unless the ILI9341 data sheet has been understood!

Updated by Bodmer 21/12/16 for TFT_eSPI library:

https://github.com/Bodmer/TFT_eSPI

BSD license applies, all text above must be included in any

redistribution

*************************************************************/

This file is based on

https://github.com/m5stack/M5Stack/blob/master/examples/Advanced/Display/TFT_Terminal/TFT_Terminal.ino

This file is modified by epi

#include <M5Stack.h>

// The scrolling area must be a integral multiple of TEXT_HEIGHT

#define TEXT_HEIGHT 24 // Height of text to be printed and scrolled

#define TOP_FIXED_AREA 24 // Number of lines in top fixed area (lines counted from top of screen)

#define BOT_FIXED_AREA 0 // Number of lines in bottom fixed area (lines counted from bottom of screen)

#define YMAX 240 // Bottom of screen area

#define XMAX 320

// The initial y coordinate of the top of the scrolling area

uint16_t yStart = TOP_FIXED_AREA;

// yArea must be a integral multiple of TEXT_HEIGHT

uint16_t yArea = YMAX - TOP_FIXED_AREA - BOT_FIXED_AREA;

// The initial y coordinate of the top of the bottom text line

uint16_t yDraw = YMAX - BOT_FIXED_AREA - TEXT_HEIGHT;

//uint16_t yDraw = 0;

// Keep track of the drawing x coordinate

uint16_t xPos = 0;

// For the byte we read from the serial port

byte data = 0;

// A few test variables used during debugging

boolean change_colour = 1;

boolean selected = 1;

// font type

// 1: 8 pixel ASCII

// 2: 16 pixel ASCII

// 4: 24 pixel ASCII

uint16_t fontType = 4;

// We have to blank the top line each time the display is scrolled, but this takes up to 13 milliseconds

// for a full width line, meanwhile the serial buffer may be filling... and overflowing

// We can speed up scrolling of short text lines by just blanking the character we drew

//int blank[19]; // We keep all the strings pixel lengths to optimise the speed of the top line blanking

// ##############################################################################################

// Setup the vertical scrolling start address pointer

// ##############################################################################################

void scrollAddress(uint16_t vsp)

{

M5.Lcd.writecommand(ILI9341_VSCRSADD); // Vertical scrolling pointer

M5.Lcd.writedata(vsp >> 8);

M5.Lcd.writedata(vsp);

}

// ##############################################################################################

// Call this function to scroll the display one text line

// ##############################################################################################

int scroll_line()

{

int yTemp = yStart; // Store the old yStart, this is where we draw the next line

// Use the record of line lengths to optimise the rectangle size we need to erase the top line

// M5.Lcd.fillRect(0,yStart,blank[(yStart-TOP_FIXED_AREA)/TEXT_HEIGHT],TEXT_HEIGHT, TFT_BLACK);

M5.Lcd.fillRect(0, yStart, XMAX, TEXT_HEIGHT, TFT_BLACK);

// Change the top of the scroll area

yStart += TEXT_HEIGHT;

// The value must wrap around as the screen memory is a circular buffer

if (yStart >= YMAX - BOT_FIXED_AREA)

yStart = TOP_FIXED_AREA + (yStart - YMAX + BOT_FIXED_AREA);

//if (yStart >= YMAX) yStart = 0;

// Now we can scroll the display

scrollAddress(yStart);

return yTemp;

}

// ##############################################################################################

// Setup a portion of the screen for vertical scrolling

// ##############################################################################################

// We are using a hardware feature of the display, so we can only scroll in portrait orientation

void setupScrollArea(uint16_t tfa, uint16_t bfa)

{

M5.Lcd.writecommand(ILI9341_VSCRDEF); // Vertical scroll definition

M5.Lcd.writedata(tfa >> 8); // Top Fixed Area line count

M5.Lcd.writedata(tfa);

M5.Lcd.writedata((YMAX - tfa - bfa) >> 8); // Vertical Scrolling Area line count

M5.Lcd.writedata(YMAX - tfa - bfa);

M5.Lcd.writedata(bfa >> 8); // Bottom Fixed Area line count

M5.Lcd.writedata(bfa);

}

void termPutchar(char data)

{

// while (Serial.available())

{

// data = Serial.read();

// If it is a CR or we are near end of line then scroll one line

if (data == '\r' || xPos > 311)

{

xPos = 0;

yDraw = scroll_line(); // It can take 13ms to scroll and blank 16 pixel lines

}

if (data > 31 && data < 128)

{

xPos += M5.Lcd.drawChar(data, xPos, yDraw, fontType);

//blank[(18+(yStart-TOP_FIXED_AREA)/textHeight)%19]=xPos; // Keep a record of line lengths

}

//change_colour = 1; // Line to indicate buffer is being emptied

}

void termPrintString(const char *str)

{

while (*str)

termPutchar(*str++);

}

void termInit(const char *title)

{

// Setup the TFT display

// M5.Lcd.setRotation(5); // Must be setRotation(0) for this sketch to work correctly

M5.Lcd.fillScreen(TFT_BLACK);

M5.Lcd.setTextColor(TFT_WHITE, TFT_BLUE);

M5.Lcd.fillRect(0, 0, XMAX, TEXT_HEIGHT, TFT_BLUE);

M5.Lcd.drawCentreString(title, XMAX / 2, 0, fontType);

// Change colour for scrolling zone text

M5.Lcd.setTextColor(TFT_WHITE, TFT_BLACK);

// Setup scroll area

setupScrollArea(TOP_FIXED_AREA, BOT_FIXED_AREA);

//setupScrollArea(0, 0);

// Zero the array

//for (byte i = 0; i<18; i++) blank[i]=0;

}

platformio.ini

; PlatformIO Project Configuration File
;
;   Build options: build flags, source filter
;   Upload options: custom upload port, speed and extra flags
;   Library options: dependencies, extra library storages
;   Advanced options: extra scripting
;
; Please visit documentation for the other options and examples
; https://docs.platformio.org/page/projectconf.html

[env:m5stack]
platform = espressif32
board = m5stack-grey
framework = arduino

  
; Serial Monitor options
monitor_speed = 115200

; PlatformIO Project Configuration File

;

; Build options: build flags, source filter

; Upload options: custom upload port, speed and extra flags

; Library options: dependencies, extra library storages

; Advanced options: extra scripting

;

; Please visit documentation for the other options and examples

; https://docs.platformio.org/page/projectconf.html

[env:m5stack]

platform = espressif32

board = m5stack-grey

framework = arduino

; Serial Monitor options

monitor_speed = 115200

動作状況

起動したばかりの時を除いて最小値は、0.020ppmのようだ。これより小さい値は出力されない。0.001ppmの桁まで変化する。

アマゾンで3千円台で購入した手元の小型のオゾン脱臭器を動作させて、脱臭器のすぐ近くにセンサーを置くと測定値は、0.1ppm を超えたが、0.5ppmを超えることはなかった。1mくらい離れたところにセンサーを置くとオゾン脱臭器動作中は0.05ppm以下。脱臭器を止めてしばらく経てば、0.020ppm になった。オゾン臭を感じられない場合でも、センサーで脱臭器が動作していることは確認できた。

一方、オゾン脱臭器を動作させておらず、臭気を感じない場合でも、0.035ppmくらいになることがある。しかし、これがセンサーの誤差によるものなのか、センサーに影響する NO2やCl2などのガスのせいなのか、イオンを発生させる機能がついているエアコンからO3も少し出ているのせいなのか、それとも他の原因があるのかははっきりしなかった。