TermIO

TermIO is a home-made indoor temperature and humidity device. It is a DIY project that uses a DHT11 sensor to measure temperature and humidity and a 4 digit seven segment display/OLED Display to show the data.

• Version 1 of the device is powered by the Arduino Nano 33 IoT + a DHT11 sensor + a 4 digit seven segment display.

• Version 2 of the device is powered by the ESP8266(Wemos D1 Mini Pro) + a DHT11 sensor + a 0.91" OLED display.

TermIO Ver. 1 vs Ver. 2

Homebridge UI & Home App on macOS

Features

• Temperature and humidity measurement.
• It computes the Apparent temperature (feels like).
• Display of the temperature and humidity on 4 digit seven segment display/OLED Display.
• It uses the NANI WiFi/ESP8266 WiFi module to connect to the internet and send the data to a server/hub/etc.
• Connects to Homebridge with a HTTP Webhook plugin to show the data on HomeKit.

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Getting Started

1. Install Homebridge on a RaspberryPi (or similar) Click me for instructions

2. Install HTPP Webhooks Plugin via Homebridge UI by accesing homebridge.local on your browser.

3. Set two new devices:

   • ID: termio-temperature as temperature sensor
   • ID: termio-humidity as humidity sensor

4. Build the circuit using the schematics (ClickMe) based on the board you are using. (Arduino Nano 33 or ESP8266).

⚠️ Only the ESP8266 Version of termio supports Homebridge for now ⚠️

5. Clone this repository and open it with the PlatformIO IDE. Be aware to open the right folder depending on your development board.

   git clone https://github.com/johannstark/TermIO.git

6. Create include/secret.h header file to contain the WiFi credentials to be use by TermIO.

   char ssid[] = "xyz";          
   char pass[] = "xyz"; 

7. Make sure the host and port of homebridge is rightly set on the code (main.cpp:44 -> Line 44):

   String hub_url = "http://homebridge.local:51828/";

8. Build and upload the code to your development board using PlatformIO.

9. PowerUp the device and check readings

10. Use the QR Code on the Homebridge UI to add a Hub to your Home App on iOS or MacOS

11. Enjoy!

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Hardware

TermIO has 2 working versions:

Arduino Nano 33 IoT

TermIO V1 works with the Arduino Nano 33 IoT that Features:

• Built-in WiFi and Low Energy Bluetooth.
• It is powered by a 32 bit Arm® Cortex®-M0 processor.
• Works with the Arduino Framework.
• It has a Micro USB port for power and programming.
• 3.3V logic level.

We use a DHT11 sensor for measuring temperature and humidity.

Displaying the temperature is done with a generic 4 digit seven segment display.

Wemos D1 Mini Pro

We made a second version of the device using a ESP8266 chip onboard of the Wemos D1 Mini Pro. This board features:

• A ESP8266 WiFi chip with a Tensilica L106 32-bit RISC processor.
• Built-in antenna
• Work with Arduino, MicroPython and NodeMCU frameworks.
• Also 3.3V logic level.

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Building the circuit

Here are the main schematics to connect the components to the development board. I suggest to power the entire circuit with a breadboard power supply that delivers both 5V and 3.3V from a 12V socket or USB cable.

⚠️ POWER THE CIRCUIT WITH 3.3V ⚠️

BOM (Bills of Materials)

• x1 DHT11 sensor
• x1 Breadboard power supply module (or any way to power 3.3V)
• x1 micro USB cable (to upload your code from the PC!)

For the Arduino Nano version, you will also need:

• x1 Seven segment display (in this case a 3461AS display)
• x6 330Ω resistors
• x2 LEDs (any color would be ok)

or if you go with the Wemos board:

• x1 0.91" OLED display
• x1 Wemos D1 Mini Pro

Arduino Nano schematics

D1 Mini Pro schematics

Software

C++ Code built with the amazing PlatformIO IDE using the Arduino framework for both Nano 33 IoT and the ESP 8266, via VS Code.

Libraries used in the project:

• Adafruit DHT Sensor Library
• Adafruit Unified Sensor (Dependency of the DHT Sensor Library)
• SevSeg by Dean Reading (Arduino Seven segment display library)
• Adafruit's GFX and SSD1306 libraries (OLED Display library)

Similar projects:

• ESP32 Pool Thermometer

License

This project is licensed under the MIT License - see the LICENSE file for details.

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Built with Love ❤️ in Colombia 🇨🇴