“An easy to build simple weather station that connects to your smartphone via WiFi and Blynk.
There are a lot a apps out there that allow you to connect your smartphone to the Internet of Things. I have tried a bunch of them and have usually been disappointed. Not so with Blynk! It is really flexible, has a beautiful user interface, works with all kinds of IoT platforms, and runs on both Android and iPhone. It is also free for hobbyists! So this is a relatively simple IoT project that allowed me to explore using Blynk.
The hardware for this project is fairly simple. We use the Arduino Nano 33 IoT which handles WiFi, a BME280 sensor board with temperature, humidity and barometric pressure all in one unit, and a 1 inch OLED display. All three run fine at 3.3 volts. The display is obviously optional - the goal is to get the weather station displaying on your phone. But it makes it much easier to get everything up and running on the OLED display first, before dealing with Blynk and your smartphone.
The schematic below shows how the hardware is interconnected. Both the sensor and the display interface with I2C. In theory, one I2C can support multiple devices, but the libraries of the sensor and display had some conflicts, so I ended up with two different I2C ports. The sensor uses the normal default I2C port at analog pins 4 and 5. The display uses a secondary I2C port set up at digital pins 4 and 5. (And yes, they are reversed - SDA is digital pin 5))”