Receive MQTT messages on arduino and display when it has to dispense

arduino/.gitignore

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+secrets.h
+

arduino/Makefile

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+compile:
+	arduino-cli compile --fqbn arduino:samd:mkrwifi1010
+
+run: compile
+	sudo arduino-cli upload --fqbn arduino:samd:mkrwifi1010 --port /dev/ttyACM0
+	sudo cat /dev/ttyACM0
+

arduino/arduino.ino

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+#include <Arduino_MKRIoTCarrier.h>
+#include <WiFiNINA.h>
+#include <ArduinoMqttClient.h>
 
-void setup() {
+#include "secrets.h"
+
+MKRIoTCarrier carrier;
+WiFiSSLClient wifi_client;
+MqttClient mqtt_client(wifi_client);
+
+extern const char *wifi_ssid;
+extern const char *wifi_password;
+
+extern const char *mqtt_server;
+extern const char *mqtt_username;
+extern const char *mqtt_password;
+
+void setup(void)
+{
+	Serial.begin(9600);
+
+	Serial.println("Started");
+
+	carrier.begin();
+	carrier.display.init(240, 240);
+
+	pinMode(TFT_BACKLIGHT, OUTPUT);
+	digitalWrite(TFT_BACKLIGHT, HIGH);
+
+	carrier.display.setCursor(20, 100);
+	carrier.display.setTextSize(3);
+	carrier.display.print("Connecting..");
+
+	Serial.println("Connecting to WiFi...");
+
+	if (wifi_enterprise) WiFi.beginEnterprise(wifi_ssid, wifi_username, wifi_password);
+	else WiFi.begin(wifi_ssid, wifi_password);
+
+	while (WiFi.status() != WL_CONNECTED) delay(1000);
+
+	Serial.println("Connected to WiFi, connecting to MQTT...");
+
+	mqtt_client.setUsernamePassword(mqtt_username, mqtt_password);
+	if (!mqtt_client.connect(mqtt_server, 8883)) {
+		Serial.print("MQTT connection failed with error code: ");
+		Serial.println(mqtt_client.connectError());
+		return;
 	}
 
-void loop() {
+	Serial.println("Connected to MQTT");
+
+	mqtt_client.subscribe("dispense");
+
+	carrier.display.fillScreen(0x000);
 }
+
+void loop(void)
+{
+	int message_size = mqtt_client.parseMessage();
+	if (message_size) {
+		Serial.print("Got message with topic: ");
+		Serial.println(mqtt_client.messageTopic());
+
+		if (mqtt_client.messageTopic() == "dispense") {
+			Serial.println("Dispensing...");
+
+			// TODO Connect to motor
+
+			carrier.display.fillScreen(0x000);
+			carrier.display.setCursor(20, 100);
+			carrier.display.setTextSize(4);
+			carrier.display.print("Dispense");
+
+			delay(500);
+
+			carrier.display.fillScreen(0x000);
+		}
+	}
+}
+

arduino/secrets.template.h

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+#include <stdbool.h>
+
+// Copy this file to secrets.h and fill out the values
+
+const bool wifi_enterprise = false;
+const char *wifi_ssid = "Wifi-name";
+const char *wifi_username = ""; // Only used if wifi_enterprise = true
+const char *wifi_password = "password";
+
+const char *mqtt_server = "example.hivemq.cloud";
+const char *mqtt_username = "username";
+const char *mqtt_password = "password";
+