新增 PM2.5 Homekit 裝置

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手上買了一個Sharp GP2Y1010AU0F PM2.5的感測器，就只在買來的當下用UNO測試了一下，嗯~~可用，就收起來了，一直到這次要整合在一個能夠顯示時間又有Homekit功能的系統板上(暫且稱它為家庭顯示中心吧)，才又把它拿出來了。

把UNO的code  Ctrl+C、Ctrl+V到ESP32下，理論上應該是沒問題的，所以就做啦，只把Delay的部分修改為vTaskDelay，因為我是採用ESP-IDF + RTOS + Arduino 的平台，Flash完，怎麼收到的電壓都是0V，用VR分壓測試，A/D沒問題啊，怎麼沒收到GP2Y的電壓，換回UNO，一切正常啊，甚麼問題???

好，Hardward沒問題，Firmware我只修改Delay，問題不會就在這吧

沒錯，在UNO下的Delay是

delayMicroseconds(280)

ESP32是

vTaskDelay(280/portTICK_RATE_MS)

這可是差1000倍呀!!

既然在ESP-IDF下已經有支援arduino的套件，那就在這裡也改用delayMicroseconds函數吧，應該不至於影響整個系統太多，畢竟我還有其他task在執行

compiler...  flash... run... ，Yes~ got it ，讀到值啦，那就繼續往下一步去，增加到Homekit裝置

新增Homekit裝置時，都需要滿足Apple的service與characteristics定義，但因為我不是ios developer，所以也不知道定義的方式為何，不過沒關係，網路上很多神人的，下面就有一個 characteristics.h 的定義檔可以參考

characteristics.h

用一個開關當範例說明 (參考characteristics.h)

在SERVICE中需要的的是ON這個Characteristics
NAME就列為選項，可有可無了

/**
 Defines that the accessory contains a switch.
 
 Required Characteristics:
 - ON
 
 Optional Characteristics:
 - NAME
 */
#define HOMEKIT_SERVICE_SWITCH HOMEKIT_APPLE_UUID2("49")

而ON這個Characteristics的定義如下

(第6行).permissions中有read、write與notify三個函數
(第9行).value中描述值為BOOL

所以我們共要有三個函數加一個BOOL值

#define HOMEKIT_CHARACTERISTIC_ON HOMEKIT_APPLE_UUID2("25")
#define HOMEKIT_DECLARE_CHARACTERISTIC_ON(_value, ...) \
    .type = HOMEKIT_CHARACTERISTIC_ON, \
    .description = "On", \
    .format = homekit_format_bool, \
    .permissions = homekit_permissions_paired_read \
                 | homekit_permissions_paired_write \
                 | homekit_permissions_notify, \
    .value = HOMEKIT_BOOL_(_value), \
    ##__VA_ARGS__

回到程式碼中，(第13行)struct hap\_characteristic switch1[]中
switch\_state 就是.value的 BOOL 定義，true 就是switch on，false即為switch off
switch1\_read、switch1\_write與switch1\_notify 就分別是三個函數啦

void *accessory_object = hap_accessory_add(acc);
    struct hap_characteristic cs[] = {
        {HAP_CHARACTER_IDENTIFY, (void *)true, NULL, identify_read, NULL, NULL},
        {HAP_CHARACTER_MANUFACTURER, (void *)MANUFACTURER_NAME, NULL, NULL, NULL, NULL},
        {HAP_CHARACTER_MODEL, (void *)MODEL_NAME, NULL, NULL, NULL, NULL},
        {HAP_CHARACTER_NAME, (void *)ACCESSORY_NAME, NULL, NULL, NULL, NULL},
        {HAP_CHARACTER_SERIAL_NUMBER, (void *)"0123456789", NULL, NULL, NULL, NULL},
        {HAP_CHARACTER_FIRMWARE_REVISION, (void *)"1.0", NULL, NULL, NULL, NULL},
    };
    hap_service_and_characteristics_add(acc, accessory_object, HAP_SERVICE_ACCESSORY_INFORMATION, cs, ARRAY_SIZE(cs));


struct hap_characteristic switch1[] = {
        {HAP_CHARACTER_ON, (void *)switch_state,NULL, switch1_read, switch1_write, switch1_notify},
    };
    hap_service_and_characteristics_add(acc, accessory_object, HAP_SERVICE_SWITCHS, switch1, ARRAY_SIZE(switch1));

switch1\_read、switch1\_write與switch1\_notify 三個函數範例程式如下

void *switch1_read(void *arg)
{
    return (void *)switch_state;
}

void switch1_write(void *arg, void *value, int len)
{
    switch_state= ((int)value) ? true : false;

    if (switch_state)
        LED_ON();
    else
        LED_OFF();

    if (_switch1_ev_handle)
        hap_event_response(acc, _switch1_ev_handle, (void *)switch_state);
    return;
}

void switch1_notify(void *arg, void *ev_handle, bool enable)
{
    if (enable)
        _switch1_ev_handle = ev_handle;
    else
        _switch1_ev_handle = NULL;
}

好了，進入主題了，新增PM2.5的Homekit裝置

當我們要使用 air quality 時，需要AIR\_QUALITY的Characteristics，PM2\.5(PM25_DENSITY) 則是列為選項

/**
 Defines that the accessory contains a air quality sensor.
 Required Characteristics:
 - AIR_QUALITY
 
 Optional Characteristics:
 - NAME
 - STATUS_ACTIVE
 - STATUS_FAULT
 - STATUS_TAMPERED
 - STATUS_LOW_BATTERY
 - OZONE_DENSITY
 - NITROGEN_DIOXIDE_DENSITY
 - SULPHUR_DIOXIDE_DENSITY
 - PM25_DENSITY
 - PM10_DENSITY
 - VOC_DENSITY
 - CARBON_MONOXIDE_LEVEL
 - CARBON_DIOXIDE_LEVEL
 */
#define HOMEKIT_SERVICE_AIR_QUALITY_SENSOR HOMEKIT_APPLE_UUID2("8D")

來看看 AIR\_QUALITY 的Characteristics
.permissions 列出 read與notitfy
.value 是 0, 1, 2, 3, 4, 5，共六個有效值

#define HOMEKIT_CHARACTERISTIC_AIR_QUALITY HOMEKIT_APPLE_UUID2("95")
#define HOMEKIT_DECLARE_CHARACTERISTIC_AIR_QUALITY(_value, ...) \
    .type = HOMEKIT_CHARACTERISTIC_AIR_QUALITY, \
    .description = "Air Quality", \
    .format = homekit_format_uint8, \
    .permissions = homekit_permissions_paired_read \
                 | homekit_permissions_notify, \
    .min_value = (float[]) {0}, \
    .max_value = (float[]) {5}, \
    .min_step = (float[]) {1}, \
    .valid_values = { \
        .count = 6, \
        .values = (uint8_t[]) { 0, 1, 2, 3, 4, 5 }, \
    }, \
    .value = HOMEKIT_UINT8_(_value), \
    ##__VA_ARGS__

PM25\_DENSITY 的Characteristics
.permissions 列出 read與notitfy
.value 是 0~1000 的範圍

#define HOMEKIT_CHARACTERISTIC_PM25_DENSITY HOMEKIT_APPLE_UUID2("C6")
#define HOMEKIT_DECLARE_CHARACTERISTIC_PM25_DENSITY(_value, ...) \
    .type = HOMEKIT_CHARACTERISTIC_PM25_DENSITY, \
    .description = "PM25 Density", \
    .format = homekit_format_float, \
    .permissions = homekit_permissions_paired_read \
                 | homekit_permissions_notify, \
    .min_value = (float[]) {0}, \
    .max_value = (float[]) {1000}, \
    .value = HOMEKIT_FLOAT_(_value), \
    ##__VA_ARGS__

有上面這些資料，就可以變成我們的code了，範例如下

struct hap_characteristic air_quality[] = {
    {HAP_CHARACTER_AIR_QUALITY , (void *)air_quality_value,NULL, air_quality_read, NULL, air_quality_notify},
    {HAP_CHARACTER_PM2_5_DENSITY , (void *)pm25_ugm3_value,NULL, pm25_ugm3_read, NULL, pm25_ugm3_notify},
}  
hap_service_and_characteristics_add(acc, accessory_object, HAP_SERVICE_AIR_QUALITY_SENSOR , air_quality,ARRAY_SIZE(air_quality));

寫完，收工~~~~~~