Remote monitoring has never been easier since the introduction of low-cost sensor modules, and wireless transmitters hit the market. Anyone looking to build a wireless sensor network for monitoring and recording environmental data, Instructables user Andrei Erdei has created an easy to follow walkthrough on how to do just that using an ATtiny85 and 443MHz transmitter. The idea here is to make what Erdei calls sensor-senders, along with a single receiver that uses very little power out in the field.
Erdei explains, “For this experiment, I chose to use sensor-senders that I built by my own using affordable modules. The receiver is also DIY, the communication is unidirectional (on the 433 MHz radio band), meaning that the sensors only transmit the data and the central location only receives.” In this instance, the sensors don’t communicate with each other, and neither is there communication from the receiver to said sensors, which cuts down on the amount of power that’s used.
For his project, Erdei assembled five wireless sensors, each with the same hardware, including an ATtiny85 microcontroller, 8-pin DIP IC socket, DHT11 temperature/humidity sensor, H34A 433MHz transmitter module, and a power supply with four AA batteries. The wireless sensors remain in deep-sleep mode until the microcontroller wakes them to garner data or to transmit that data to the receiver.
For the receiver, Erdei used an Arduino Uno, H3VF4 receiving module, and an arc antenna, all packed into a simple housing. It should be noted at this point that the 433MHz frequency, while free to use in some countries, requires an Amateur Radio Operator’s License in the US. That said, Erdei has provided an excellent walkthrough of his build for anyone looking to recreate his Low-Cost Wireless Sensor Network.