Setting Up a Thing

Learning Goals 5 min

End-to-end: register a board as a Device, create a Thing, add two Properties (one read-only sensor, one read-write toggle), upload the auto-generated sketch, and watch the values update in real time. By the end of this lesson you will:

1. Register a supported board (UNO R4 WiFi, MKR WiFi 1010, Nano 33 IoT, Nano ESP32) as an Arduino Cloud Device.
2. Create a Thing, attach the device, and add two Properties.
3. Upload the auto-generated sketch and confirm the sensor reading appears in the Property's value field within seconds.

Warm-Up 10 min

Have ready:

• A supported board (see L04-07 list). For this lesson we'll assume Nano ESP32.
• USB cable.
• A potentiometer on A0 (the "sensor") and an LED on D2 with a 220 Ω resistor (the "actuator").
• WiFi credentials for the network the board will use.
• Arduino account, signed into create.arduino.cc.

Mental map of the steps

1. Register the device — give the cloud an ID for this specific board.
2. Create a Thing — name + add Properties.
3. Configure network — enter WiFi SSID + password (stored as secrets).
4. Auto-generate sketch — IoT Cloud writes thingProperties.h for you.
5. Upload — via the web IDE or your local IDE.
6. Watch the Property update.

New Concept · Walkthrough 25 min

Step 1 — Devices tab

In IoT Cloud → Devices → Add Device. Pick "Arduino board" (vs "Third-party device", which is for ESP8266 / non-Arduino ESP32). The wizard auto-detects boards plugged in via USB.

Pick your board model. The wizard installs the Arduino Cloud Agent (a small helper app), assigns a unique Device ID and a secret Device Key. Save these somewhere safe — the key is shown ONCE and never again.

Step 2 — Things tab

Things → Create Thing. Name it (e.g. "DeskMonitor"). Attach the Device you just registered.

Step 3 — Add Properties

• potValue: integer, READ permission, On Change update policy.
• ledOn: boolean, READWRITE permission, On Change.

Each Property has:

• Variable name (becomes a C++ variable in the sketch).
• Type (int, bool, float, String, or a domain type like Temperature).
• Permission: READ (sketch → cloud), WRITE (cloud → sketch), READWRITE (bidirectional).
• Update policy: On Change (push when value differs) or Periodically (push every N seconds).

Step 4 — Network

Click the Network field. Enter SSID + password. These become SECRET_SSID and SECRET_OPTIONAL_PASS — stored encrypted on the cloud side and injected into the sketch at upload time. Never visible in plain text in your codebase.

Step 5 — Sketch

The Sketch tab shows the auto-generated .ino. You can edit it in the browser or download it.

#include "thingProperties.h"

void setup() {
  Serial.begin(9600);
  delay(1500);
  initProperties();
  ArduinoCloud.begin(ArduinoIoTPreferredConnection);
  setDebugMessageLevel(2);
  ArduinoCloud.printDebugInfo();

  pinMode(2, OUTPUT);
}

void loop() {
  ArduinoCloud.update();
  potValue = analogRead(A0);
}

void onLedOnChange() {
  digitalWrite(2, ledOn ? HIGH : LOW);
  Serial.print("LED -> ");
  Serial.println(ledOn ? "ON" : "OFF");
}

Step 6 — Upload

From the web IDE: click Upload. Watch the build log + the board's status (Devices tab shows "online" / "offline").

From your local IDE: download the sketch + thingProperties.h, open as a normal Arduino project. The libraries (ArduinoIoTCloud + Arduino_ConnectionHandler) must be installed locally; auto-installed if you compile from the web IDE.

Step 7 — Watch the Property

In the Thing's Properties tab: potValue should update every second or so as you turn the pot. ledOn has a switch you can toggle; the LED on D2 should respond within ~1 s.

Worked Example · DeskMonitor in 15 minutes 25 min

Follow the §3 steps live. Verify everything works.

If it didn't work

Add a third Property

Now add uptime (int, READ, Periodically every 10 s). Update in loop():

uptime = millis() / 1000;

The IoT Cloud handles the periodic publishing — you don't need a millis() timer.

Watch the serial monitor

The Cloud library is chatty when setDebugMessageLevel(2) is set. You'll see:

Connecting to "your-wifi"
Connected to WiFi
Connecting to Arduino IoT Cloud
Connected to Arduino IoT Cloud
*** Tx properties (~1 s) ***
*** Rx properties ***

If you see "Connecting" forever, the WiFi credentials are wrong or the network is unreachable.

Try It Yourself 15 min

void onColorChange() {
  uint8_t r, g, b;
  color.getValue().getRGB(r, g, b);
  analogWrite(R_PIN, r);
  analogWrite(G_PIN, g);
  analogWrite(B_PIN, b);
}

Mini-Challenge · Document your Thing 10 min

1. Open the Things tab → click your Thing → Properties view.
2. Take a screenshot.
3. Paste into a notebook page (digital or paper) and label each Property: name, type, permission, what it physically does.
4. Tomorrow we build dashboards around these properties.

Recap 5 min

Setting up a Thing is: register device → create Thing → add properties → set WiFi → upload generated sketch. The hidden thingProperties.h file holds all the boilerplate (WiFi, device key, MQTT). Your .ino stays tiny — just sensor reads and callback bodies. Tomorrow we visualise the properties with dashboard widgets.

Cloud Agent

Small helper app on your computer that lets the web IDE upload to USB-connected boards.

Device ID / Device Key

Unique per-device credentials used to authenticate the board to the cloud. The Key is shown once at registration.

Update policy

How / when a property pushes. "On Change" = whenever value differs. "Periodically" = every N seconds regardless.

Permission

READ = device pushes only. WRITE = cloud pushes only. READWRITE = both directions.

Callback (on<Name>Change)

Function called when a READWRITE property is updated from the cloud. Name must match the property: onLedOnChange() for ledOn.

Secret

Sensitive value (WiFi password, API key) stored in the cloud's secrets manager, never visible in shared sketches.

thingProperties.h

Auto-generated header with property declarations, WiFi setup, and the initProperties() function.

Homework 5 min

1. Get DeskMonitor working end-to-end. Screenshot the Properties view with values updating.
2. Read ahead to ARD-L04-09 (Cloud Dashboards). Tomorrow we add widgets.