Arduino IoT Cloud - Temperature Monitor


Looking for a super easy and simple cloud service platform? This might be a good fit for you! There is also a free version to get you started, so that’s a nice perk as well.

I was also happy to see they have a mobile app you can use to view your dashboards:



You can setup very easily with this using any ESP32 board, but this tutorial is specific to using the trigBoard and a temperature sensor. Hopefully, this tutorial will show you how to set this up with any kind of sensor with the trigBoard (or no sensor at all - just contact status)


You can use this without

The wiring is simple - just need an MCP9808 Breakout Board from Adafruit which is a very accurate, fast, and reliable temperature sensor. Can also get these boards on Amazon for much cheaper.

_images/MCP9808wiringwithtrigboard.png _images/MCP9808Installed.png

Or even cleaner:


Arduino IoT Cloud Setup

First thing to do is login to your account at Arduino IoT Cloud

Then let’s just get started and create a device - will be a third party board:


Will be ESP32, and select Dev Module:


Give the board a name!


Important save the Device ID and Secret Key - we’ll need these later


Now we see the device is created and can create a thing with variables:


Then we create variables:


For example, and as you’ll see in the code, these variable names need to line up with the actual variable used in the trigBoard code:


The example code uses three variables - pay attention to type (float, bool, etc) and since we’re just sending these up to the cloud, are read only and the periodic time doesn’t matter.


You have a Device ID, Secret Key, and now save the Thing ID at the bottom of this page - You need all three


From there, it’s all pretty easy to create dashboards to visualize the data. In the future, we’ll look at how to pull this data out of the Arduino Cloud to automate things, like turn something on/off on a threshold.

trigBoard Setup

The github repo is here

To compile this code as-is, you will need the MCP9808 library from Adafruit as well as the supporting libraries for Arduino IoT Cloud. You can install all of these libraries from the Arduino IDE, you’ll find it: sketch>>Include Library>>Manage Libraries Note, you are still compiling the base firmware, so go to the Firmware Page for what is needed to do that

What’s really cool about this code is that it re-uses other fields in the trigBoard configurator to set this up to work with Arduino IoT Cloud, so no need to hard code things.

Configurator Arduino IoT Cloud
Pushover Key Thing ID
Pushover API Token/Key Device ID
Push Safer Key Secret Key
Message when Wake Button Pressed C or F

So then when you launch the configurator, you setup your WiFi credentials, the interval time in the timer settings, then the Arduino IoT Cloud parameters.

Taking a look at the code, you’ll see how easy it is to modify variables - head over to the thingProperties.h tab:

void initProperties() {

  ArduinoCloud.addProperty(arduinoTemperature, READ, 1 * SECONDS, NULL);
  ArduinoCloud.addProperty(arduinoBatteryVoltage, READ, 1 * SECONDS, NULL);
  ArduinoCloud.addProperty(arduinoContact, READ, 1 * SECONDS, NULL);

When you scroll down there, you can see how the ArduinoCloud properties are added. These variables are declared as globals at the top of this file:

float arduinoTemperature;
float arduinoBatteryVoltage;
boolean arduinoContact;

From there, these variables are stuffed with the data we want to send up to the cloud:

Head back over to the main tab, and you’ll see how this is done:

arduinoTemperature = atof(temperatureString);
arduinoBatteryVoltage = getBattery();
arduinoContact = contactStatusClosed;//arduinoContact=true when contact closed