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--- inhabitat:kaunas:day02 [2026/05/29 09:01] – jan.sonntag
+++ inhabitat:kaunas:day02 [2026/05/29 09:05] (current) – jan.sonntag
@@ Line 21: / Line 21: @@
 We are using the **DFRobot Analog Capacitive Soil Moisture Sensor**.
-{{ :day2:soil_sensor.jpg?400 |}}
-<wrap em>📷 PLACEHOLDER — Insert a photo of the DFRobot capacitive soil moisture sensor here.</wrap>
 ===== 2. Connecting the Sensor to the DOIT ESP32 =====
@@ Line 40: / Line 37: @@
   * Double-check GND is shared between the sensor and the board.
-{{ :day2:wiring_diagram.png?500 |}}
+<WRAP center round tip 60%>
-<wrap em>📷 PLACEHOLDER — Insert the wiring diagram / photo showing
+Here an example to connect to similiar MCU. Make sure to check the Pinout of your specific board!
+</WRAP>
+<imgcaption image3|Wiring of the analog sensor>{{ https://raw.githubusercontent.com/EOLab-HSRW/intro-to-iot/master/diagrams/wemos-soil_bb.png?400 |}}</imgcaption>
+<imgcaption image4|Schematic>{{ https://raw.githubusercontent.com/EOLab-HSRW/intro-to-iot/master/diagrams/wemos-soil_schematic.png?400 |}}</imgcaption>
+===== 3. Reading the Sensor with the Serial Monitor =====
+Before we send data anywhere, we want to **see** it. The easiest way is the
+**Serial Monitor**.
+**Serial** is a way for the ESP32 to send text back to your computer over the
+USB cable. By calling ''Serial.begin()'' once at startup and then
+''Serial.println()'' whenever we have something to show, we can print our
+sensor readings to the screen in real time. This is incredibly useful for
+checking that everything is wired correctly and that the numbers change when
+you touch the sensor or place it in soil.
+Open the Serial Monitor in PlatformIO and make sure the **baud rate matches**
+the value you set in ''Serial.begin()'' (commonly 115200).
+<code cpp>
+// PLACEHOLDER — Sensor reading code
+// This should:
+//   - start Serial at the chosen baud rate in setup()
+//   - read the analog value from the sensor pin
+//   - print the value to the Serial Monitor in loop()
+//   - add a short delay so the output is readable
+</code>
+Once uploaded, you should see numbers scrolling in the Serial Monitor.
+Try touching the sensor or dipping it into soil/water — the value should change.
+===== 4. Connecting to WiFi =====
+Now that the board works on its own, let's get it online. The ESP32 has
+built-in WiFi, so we just need to give it the **network name (SSID)** and
+**password** of our workshop access point.
+In ''setup()'' we tell the ESP32 to connect, then wait in a short loop until
+the connection succeeds. We can print the status to Serial so we know when
+we're online.
+<code cpp>
+// PLACEHOLDER — WiFi connection code
+// This should:
+//   - include the WiFi library
+//   - store the SSID and password
+//   - start the connection in setup()
+//   - wait until connected, printing progress to Serial
+//   - print the assigned IP address once connected
+</code>
+When it works, the Serial Monitor will show that the ESP32 has joined the
+network and received an IP address.
+===== 5. Introducing MQTT =====
+**MQTT** is a lightweight messaging protocol that is very popular in IoT. The
+idea is simple: devices send ("**publish**") messages to a central server (the
+"**broker**"), and other devices can listen ("**subscribe**") for them. Today
+we will only **publish** — sending messages out. We will not subscribe.
+{{pdfjs 500px>:latinet:unicaes:workshops:mqtt.pdf?75}}
+===== 6. Publishing a Message to the Broker =====
+For our final step, we connect to the **MQTT broker** and send a single
+message of **your choosing** — any text string you like, for example
+''"hello from my esp32"''.
+  * This is **not** the soil moisture value. That's a separate exercise. Here we are just proving we can talk to the broker by sending a simple string.
+  * We connect to the broker, then publish our chosen string to a **topic**.
+<code cpp>
+// PLACEHOLDER — MQTT publish code
+// This should:
+//   - include the MQTT client library
+//   - set the broker address and port
+//   - connect to the broker in setup() (after WiFi is connected)
+//   - publish a single text string of your choosing to a topic
+//   - print confirmation to Serial
+</code>
+Pick any message you want and send it. 🎉
+===== Recap =====
+By the end of today you have:
+  * Learned how a capacitive soil moisture sensor works
+  * Wired it to the DOIT ESP32
+  * Read its value in the Serial Monitor
+  * Connected the ESP32 to WiFi
+  * Learned the basics of MQTT
+  * Published your own message to the MQTT broker