Code cleanup

- Removed unused #define and 'using namespace'
- Moved magic literals to global const
- Reordered functions
- Changed timers in main loop to simple macro instead of Timer class
- Changed several identifiers
- Reformatted global variable assignments

operame.ino

@@ -1,4 +1,3 @@
-#define Sprintf(f, ...) ({ char* s; asprintf(&s, f, __VA_ARGS__); String r = s; free(s); r; })
 #include <WiFi.h>
 #include <MQTT.h>
 #include <SPIFFS.h>
@@ -10,26 +9,28 @@
 #include <logo.h>
 #include <list>
 
-using namespace std;
-
-unsigned long mqtt_interval;
-const int portalbutton = 35;
-const int demobutton = 0;
-bool ota_enabled;
-int co2_warning;
-int co2_critical;
-int co2_blink;
-
 enum Driver { AQC, MHZ };
 Driver          driver;
-
-int mhz_co2_init = 410;  // magic value reported while initializing
-
 MQTTClient      mqtt;
 HardwareSerial  hwserial1(1);
 TFT_eSPI        display;
 TFT_eSprite     sprite(&display);
 MHZ19           mhz;
+
+const int       pin_portalbutton = 35;
+const int       pin_demobutton   = 0;
+const int       pin_backlight    = 4;
+const int       pin_sensor_rx    = 27;
+const int       pin_sensor_tx    = 26;
+const int       pin_pcb_ok       = 12;   // pulled to GND by PCB trace
+int             mhz_co2_init     = 410;  // magic value reported during init
+
+// Configuration via WiFiSettings
+unsigned long   mqtt_interval;
+bool            ota_enabled;
+int             co2_warning;
+int             co2_critical;
+int             co2_blink;
 String          mqtt_topic;
 String          mqtt_template;
 bool            add_units;
@@ -37,21 +38,7 @@ bool wifi_enabled;
 bool            mqtt_enabled;
 int             max_failures;
 
-struct Timer {
+void retain(const String& topic, const String& message) {
-    unsigned long previous;
-    unsigned long interval;
-    std::function<void()> function;
-    void operator()() {
-        if (millis() - previous >= interval) {
-            function();
-            previous = millis();
-        }
-    }
-    Timer(unsigned long ms, std::function<void()> f)
-        : interval(ms), function(f) {}
-};
-
-void retain(String topic, String message) {
     Serial.printf("%s %s\n", topic.c_str(), message.c_str());
     mqtt.publish(topic, message, true, 0);
 }
@@ -103,47 +90,6 @@ void display_logo() {
     sprite.pushSprite(0, 0);
 }
 
-void panic(const String& message) {
-    display_big(message, TFT_RED);
-    delay(5000);
-    ESP.restart();
-}
-
-void setup_ota() {
-    ArduinoOTA.setHostname(WiFiSettings.hostname.c_str());
-    ArduinoOTA.setPassword(WiFiSettings.password.c_str());
-    ArduinoOTA.onStart(   []()              { display_big("OTA", TFT_BLUE); });
-    ArduinoOTA.onEnd(     []()              { display_big("OTA done", TFT_GREEN); });
-    ArduinoOTA.onError(   [](ota_error_t e) { display_big("OTA failed", TFT_RED); });
-    ArduinoOTA.onProgress([](unsigned int p, unsigned int t) {
-        String pct { (int) ((float) p / t * 100) };
-        display_big(pct + "%");
-    });
-    ArduinoOTA.begin();
-}
-
-bool button(int pin) {
-    if (digitalRead(pin)) return false;
-    unsigned long start = millis();
-    while (!digitalRead(pin)) {
-        if (millis() - start >= 50) display_big("");
-    }
-    return millis() - start >= 50;
-}
-
-void check_portalbutton() {
-    if (button(portalbutton)) WiFiSettings.portal();
-}
-
-void check_demobutton() {
-    if (button(demobutton)) ppm_demo();
-}
-
-void check_buttons() {
-    check_portalbutton();
-    check_demobutton();
-}
-
 void display_ppm(int ppm) {
     int fg, bg;
     if (ppm >= co2_critical) {
@@ -170,7 +116,7 @@ void ppm_demo() {
     delay(1000);
     for (int p = 400; p < 1200; p++) {
         display_ppm(p);
-        if (button(demobutton)) {
+        if (button(pin_demobutton)) {
             display_logo();
             delay(500);
             return;
@@ -181,27 +127,162 @@ void ppm_demo() {
     delay(5000);
 }
 
+void panic(const String& message) {
+    display_big(message, TFT_RED);
+    delay(5000);
+    ESP.restart();
+}
+
+bool button(int pin) {
+    if (digitalRead(pin)) return false;
+    unsigned long start = millis();
+    while (!digitalRead(pin)) {
+        if (millis() - start >= 50) display_big("");
+    }
+    return millis() - start >= 50;
+}
+
+void check_portalbutton() {
+    if (button(pin_portalbutton)) WiFiSettings.portal();
+}
+
+void check_demobutton() {
+    if (button(pin_demobutton)) ppm_demo();
+}
+
+void check_buttons() {
+    check_portalbutton();
+    check_demobutton();
+}
+
+void setup_ota() {
+    ArduinoOTA.setHostname(WiFiSettings.hostname.c_str());
+    ArduinoOTA.setPassword(WiFiSettings.password.c_str());
+    ArduinoOTA.onStart(   []()              { display_big("OTA", TFT_BLUE); });
+    ArduinoOTA.onEnd(     []()              { display_big("OTA done", TFT_GREEN); });
+    ArduinoOTA.onError(   [](ota_error_t e) { display_big("OTA failed", TFT_RED); });
+    ArduinoOTA.onProgress([](unsigned int p, unsigned int t) {
+        String pct { (int) ((float) p / t * 100) };
+        display_big(pct + "%");
+    });
+    ArduinoOTA.begin();
+}
+
+void connect_mqtt() {
+    if (mqtt.connected()) return;  // already/still connected
+
+    static int failures = 0;
+    if (mqtt.connect(WiFiSettings.hostname.c_str())) {
+        failures = 0;
+    } else {
+        failures++;
+        if (failures >= max_failures) panic("MQTT onbereikbaar");
+    }
+}
+
+int aqc_get_co2() {
+    static bool initialized = false;
+
+    const uint8_t command[9] = { 0xff, 0x01, 0xc5, 0, 0, 0, 0, 0, 0x3a };
+    uint8_t response[9];
+    int co2 = -1;
+
+    for (int attempt = 0; attempt < 3; attempt++) {
+        hwserial1.flush();
+        int limit = 20;  // .available() sometimes stays true
+        while(hwserial1.available() && --limit) hwserial1.read();
+
+        hwserial1.write(command, sizeof(command));
+        delay(50);
+        size_t c = hwserial1.readBytes(response, sizeof(response));
+        if (c != sizeof(response) || response[0] != 0xff || response[1] != 0x86) {
+            continue;
+        }
+        uint8_t checksum = 255;
+        for (int i = 0; i < sizeof(response) - 1; i++) {
+            checksum -= response[i];
+        }
+        if (response[8] == checksum) {
+            co2 = response[2] * 256 + response[3];
+            break;
+        }
+        delay(50);
+    }
+
+    if (co2 < 0) {
+        initialized = false;
+        return co2;
+    }
+
+    if (!initialized && (co2 == 9999 || co2 == 400)) return 0;
+    initialized = true;
+    return co2;
+}
+
+void mhz_setup() {
+    mhz.begin(hwserial1);
+    // mhz.setFilter(true, true);  Library filter doesn't handle 0436
+    mhz.autoCalibration(true);
+    char v[5] = {};
+    mhz.getVersion(v);
+    v[4] = '\0';
+    if (strcmp("0436", v) == 0) mhz_co2_init = 436;
+}
+
+int mhz_get_co2() {
+    int co2       = mhz.getCO2();
+    int unclamped = mhz.getCO2(false);
+
+    if (mhz.errorCode != RESULT_OK) {
+        delay(500);
+        mhz_setup();
+        return -1;
+    }
+
+    // reimplement filter from library, but also checking for 436 because our
+    // sensors (firmware 0436, coincidence?) return that instead of 410...
+    if (unclamped == mhz_co2_init && co2 - unclamped >= 10) return 0;
+
+    // No known sensors support >10k PPM (library filter tests for >32767)
+    if (co2 > 10000 || unclamped > 10000) return 0;
+
+    return co2;
+}
+
+int get_co2() {
+    // <0 means read error, 0 means still initializing, >0 is PPM value
+
+    if (driver == AQC) return aqc_get_co2();
+    if (driver == MHZ) return mhz_get_co2();
+
+    // Should be unreachable
+    panic("driverfout");
+    return -1;  // suppress warning
+}
+
 void setup() {
     Serial.begin(115200);
     Serial.println("Operame start");
     SPIFFS.begin(true);
-    pinMode(portalbutton, INPUT_PULLUP);
+
-    pinMode(demobutton, INPUT_PULLUP);
+    pinMode(pin_portalbutton,   INPUT_PULLUP);
-    pinMode(4, OUTPUT);
+    pinMode(pin_demobutton,     INPUT_PULLUP);
-    digitalWrite(4, HIGH);
+    pinMode(pin_pcb_ok,         INPUT_PULLUP);
+    pinMode(pin_backlight,      OUTPUT);
+
+    digitalWrite(pin_backlight, HIGH);
 
     display.init();
     display.fillScreen(TFT_BLACK);
     display.setRotation(1);
     sprite.createSprite(display.width(), display.height());
 
-    pinMode(12, INPUT_PULLUP);
+    while (digitalRead(pin_pcb_ok)) {
-    while (digitalRead(12)) {
         display_big("module verkeerd om!", TFT_RED);
         delay(1000);
     }
 
-    hwserial1.begin(9600, SERIAL_8N1, 27, 26);
+    hwserial1.begin(9600, SERIAL_8N1, pin_sensor_rx, pin_sensor_tx);
 
     if (aqc_get_co2() >= 0) {
         driver = AQC;
@@ -298,7 +379,7 @@ void setup() {
         }
 
         if (ota_enabled) ArduinoOTA.handle();
-        if (button(portalbutton)) ESP.restart();
+        if (button(pin_portalbutton)) ESP.restart();
     };
 
     if (wifi_enabled) WiFiSettings.connect(false, 15);
@@ -309,114 +390,17 @@ void setup() {
     if (ota_enabled) setup_ota();
 }
 
-void connect_mqtt() {
+#define every(t) for (static uint16_t _lasttime; (uint16_t)((uint16_t)millis() - _lasttime) >= (t); _lasttime += (t))
-    if (mqtt.connected()) return;  // already/still connected
-
-    static int failures = 0;
-    if (mqtt.connect(WiFiSettings.hostname.c_str())) {
-        failures = 0;
-    } else {
-        failures++;
-        if (failures >= max_failures) panic("MQTT onbereikbaar");
-    }
-}
-
-int aqc_get_co2() {
-    static bool initialized = false;
-
-    const uint8_t command[9] = { 0xff, 0x01, 0xc5, 0, 0, 0, 0, 0, 0x3a };
-    uint8_t response[9];
-    int co2 = -1;
-
-    for (int attempt = 0; attempt < 3; attempt++) {
-        hwserial1.flush();
-        int limit = 20;  // .available() sometimes stays true
-        while(hwserial1.available() && --limit) hwserial1.read();
-
-        hwserial1.write(command, sizeof(command));
-        delay(50);
-        size_t c = hwserial1.readBytes(response, sizeof(response));
-        if (c != sizeof(response) || response[0] != 0xff || response[1] != 0x86) {
-            continue;
-        }
-        uint8_t checksum = 255;
-        for (int i = 0; i < sizeof(response) - 1; i++) {
-            checksum -= response[i];
-        }
-        if (response[8] == checksum) {
-            co2 = response[2] * 256 + response[3];
-            break;
-        }
-        delay(50);
-    }
-
-    if (co2 < 0) {
-        initialized = false;
-        return co2;
-    }
-
-    if (!initialized && (co2 == 9999 || co2 == 400)) return 0;
-    initialized = true;
-    return co2;
-}
-
-void mhz_setup() {
-    mhz.begin(hwserial1);
-    // mhz.setFilter(true, true);  Library filter doesn't handle 0436
-    mhz.autoCalibration(true);
-    char v[5] = {};
-    mhz.getVersion(v);
-    v[4] = '\0';
-    if (strcmp("0436", v) == 0) mhz_co2_init = 436;
-}
-
-int mhz_get_co2() {
-    int co2       = mhz.getCO2();
-    int unclamped = mhz.getCO2(false);
-
-    if (mhz.errorCode != RESULT_OK) {
-        delay(500);
-        mhz_setup();
-        return -1;
-    }
-
-    // reimplement filter from library, but also checking for 436 because our
-    // sensors (firmware 0436, coincidence?) return that instead of 410...
-    if (unclamped == mhz_co2_init && co2 - unclamped >= 10) return 0;
-
-    // No known sensors support >10k PPM (library filter tests for >32767)
-    if (co2 > 10000 || unclamped > 10000) return 0;
-
-    return co2;
-}
-
-int get_co2() {
-    // <0 means read error, 0 means still initializing, >0 is PPM value
-
-    if (driver == AQC) return aqc_get_co2();
-    if (driver == MHZ) return mhz_get_co2();
-
-    // Should be unreachable
-    panic("driverfout");
-    return -1;  // suppress warning
-}
-
 
 void loop() {
     static int co2;
 
-    static Timer read_sensor {
+    every(5000) {
-        5000,
-        [] {
         co2 = get_co2();
         Serial.println(co2);
     }
-    };
-    read_sensor();
 
-    static Timer display {
+    every(50) {
-        50,
-        [] {
         if (co2 < 0) {
             display_big("sensorfout", TFT_RED);
         } else if (co2 == 0) {
@@ -426,22 +410,16 @@ void loop() {
             display_ppm(co2 > 9999 ? 9999 : co2);
         }
     }
-    };
-    display();
 
-    static Timer publish {
+    if (mqtt_enabled) {
-        mqtt_interval,
+        mqtt.loop();
-        [] {
+        every(mqtt_interval) {
-            if (co2 <= 0) return;
+            if (co2 <= 0) break;
             connect_mqtt();
             String message = mqtt_template;
             message.replace("{}", String(co2));
             retain(mqtt_topic, message);
         }
-    };
-    if (mqtt_enabled) {
-        mqtt.loop();
-        publish();
     }
 
     if (ota_enabled) ArduinoOTA.handle();