This project describes a DIY wireless temperature and humidity monitor for kids’ or infant’s room using the Arduino platform, and inexpensive and easily available ASK transmitter/receiver modules. On the transmitting end, an Arduino nano senses the ambient room temperature and humidity using the DHT22 sensor and transmits the data to a receiving end Arduino over a 433 MHz ASK RF link. The receiving side Arduino decodes the received bytes and displays the information on a LCD screen. The indoor range of the RF transmission is about 100 ft, which is mostly sufficient for a decent size house.
Things you will need
You will need the following items to build this project.
- ASK transmitter/receiver pair
- Two Arduino boards. I am using an Arduino Nano on transmitting side and Arduino Uno on receiving end.
- One Nokia 5110 LCD for displaying data at the receiving side
- One DHT22 sensor for measuring temperature and humidity at the transmitting en
- Two LEDs and two 330Ω resistors
- Wires, breadboard, prototyping board, etc.
Few words on ASK RF kits
There are varieties ASK Tx/Rx modules available online in both domestic and international markets (specially China). Some of them come with spring antennas, and some don’t. With the ones without antennas, you can connect ~20cm wire to their antenna pin on circuit board. The figure below shows some of the ASK RF modules you can buy on eBay and Amazon.
For this project, I used high quality ASK RF modules manufactured by NiceRF, a China-based company. You can also buy these modules directly from our Tindie store. The nice things about these modules are they are very compact, breadboard and PCB friendly, made of high-quality PCB, come with copper spring antennas and have a reasonable transmission range.