sensor station: up, down buttons

1 files changed, 65 insertions, 3 deletions

diff --git a/SensorStation/SensorStation.ino b/SensorStation/SensorStation.ino
index 4d9de86..46f792d 100644
--- a/SensorStation/SensorStation.ino
+++ b/SensorStation/SensorStation.ino
@@ -4,7 +4,12 @@
 
 #define nelem(arr) (sizeof(arr) / sizeof(arr[0]))
 
-enum { DHT_PIN = 21 };
+enum pins {
+	DHT_PIN = 21,
+
+	UP_BTN = 16,
+	DOWN_BTN = 17,
+};
 enum {
 	SECOND = 1000,
 	PERIOD = 30*SECOND,
@@ -16,11 +21,18 @@ const char domain[] = "hvac.samanthony.xyz";
 const char humidityPath[] = "/humidity";
 const char targetHumidityPath[] = "/target_humidity";
 const char roomID[] = "SNbeEcs7XVWMEvjeEYgwZnp9XYjToVhh";
+const float defaultTarget = 35.0; // Default target humidity.
+const float minTarget = 0.0; // Minimum target humidity.
+const float maxTarget = 100.0; // Maximum target humidity.
+const float incTarget = 0.5; // Target humidity increment from button press.
 
 DHT dht(DHT_PIN, DHT11); // Humidity sensor.
 
 void
 setup(void) {
+	pinMode(UP_BTN, INPUT);
+	pinMode(DOWN_BTN, INPUT);
+
 	Serial.begin(9600);
 	while (!Serial) {}
 
@@ -35,19 +47,41 @@ setup(void) {
 	Serial.println(WiFi.localIP());
 
 	Serial.print("Initializing DHT11 humidity sensor...");
+	delay(1*SECOND); /* Let sensor stabilize after power-on. */
 	dht.begin();
 	Serial.println(" done.");
 }
 
 void
 loop(void) {
+	static float targetHumidity = defaultTarget;
+	static unsigned long lastSample = 0; // Last time humidity was measured.
+
+	unsigned long now = millis();
+	if (now - lastSample > PERIOD) {
+		measureHumidity();
+		lastSample = now;
+	}
+
+	if (upButton() && targetHumidity+incTarget <= maxTarget) {
+		targetHumidity += incTarget;
+		Serial.printf("Up. Target humidity: %.2f%%\n", targetHumidity);
+		/* TODO: send target to server. */
+	} else if (downButton() && targetHumidity-incTarget >= minTarget) {
+		targetHumidity -= incTarget;
+		Serial.printf("Down. Target humidity: %.2f%%\n", targetHumidity);
+		/* TODO: send target to server. */
+	}
+}
+
+// Measure the humidity and send it to the server.
+void
+measureHumidity(void) {
 	float humidity = dht.readHumidity();
 	Serial.printf("Humidity: %.2f %% RH\n", humidity);
 
 	if (send(humidity) != 0)
 		Serial.println("Failed to send humidity to server.");
-
-	delay(PERIOD);
 }
 
 // Send the measured humidity to the server.
@@ -95,3 +129,31 @@ url(const char *domain, const char *path, const char *query) {
 		Serial.println("URL string buffer overflow; truncating.");
 	return buf;
 }
+
+// Return true if the UP button was pressed.
+bool
+upButton(void) {
+	static bool state = LOW;
+	return buttonPressed(UP_BTN, &state);
+}
+
+// Return true if the DOWN button was pressed.
+bool
+downButton(void) {
+	static bool state = LOW;
+	return buttonPressed(DOWN_BTN, &state);
+}
+
+// Return true if the button connected to the specified pin was pressed.
+bool
+buttonPressed(int pin, bool *lastState) {
+	if (digitalRead(pin)) {
+		if (*lastState == LOW) { // Rising event.
+			*lastState = HIGH;
+			return true;
+		}
+	} else { // Falling event.
+		*lastState = LOW;
+	}
+	return false;
+}