“In this paper we have presented how to implement a Weather Station to monitor various parameters:
- Temperature (indoor + outdoor);
- Humidity (indoor + outdoor);
The practical project is based on the Arduino Nano Interface and involves the use of modules and sensors:
- NRF24L01 (radio-communications);
- DHT22 (temperature and humidity sensor);
- BMP180 (pressure and altitude sensor);
- DS3231 (Real Time Clock module);
It was opted for practical construction using these sub-assemblies because they are cheap and easy to use and interconnect.
- Altitude and pressure sensor BMP180
The BMP180 is an ideal module for measuring atmospheric pressure, altitude as well as temperature, being an inexpensive and very easy to use module. It uses only I2C communications (A4 - SDA respectively A5 - SCL), measuring the absolute atmospheric pressure of the environment using a digital barometer.
In addition to the advantages of size and ease of implementation in projects, it has a very low current consumption of only 0.3uA.
- Temperature and humidity sensorDHT11/DHT22
These DHT modules are high performance temperature and humidity sensors ensuring high reliability and excellent stability. Temperature is measured using a negative temperature coefficient (NTC) thermistor and relative humidity is measured using a capacitive sensor. These sensing elements are pre-calibrated and the output is provided as a digital signal.The DHT11 is used for temperatures above 0oC, and for higher accuracy and longer operating range the DHT22 is used which can measure lower temperatures down to a maximum of -40 oC.
- ModulWireless NRF24L01
The NRF24L01 module is designed for wireless communications, using the SPI communications of the Arduino board. Being equipped with an antenna it can transmit data over longer distances (approx. 1000m in open field). The integrated circuit is a very high-function one, more details can be found in the datasheet. It has a very low power consumption (varies depending on the communication distance between the 2 modules).
- DS3231 Real Time Clock Module
The DS3231 is a highly accurate, low-cost I2C Real Time Clock (RTC) with an integrated temperature compensated crystal oscillator (TCXO) and crystal. The device incorporates a battery input and keeps the timer accurate when the main power to the device is interrupted.”