I am looking for a way of having a central Arduino that takes water sensor readings from multiple places around the garden.
So, Bluetooth is my first thought with the Arduino/Master Bluetooth polling about 8 remote devices, taking a reading and then doing something else based on the reading.
No wires between the remote sensors and the master Arduino but the remote sensors could have battery/ solar power.
Any thoughts please....
NRF24 is made for this sort of thing and makes more sense than Bluetooth. They have about the same price and performance. Your central Arduino may also have Bluetooth to communicate with the outside world.
A likely better bet is to use little ESP8266 WiFi modules in a network with a Node-MCU or maybe a PC. No Arduinos - anywhere.
Another similar option is the ESP32
This Simple nRF24L01+ Tutorial (http://forum.arduino.cc/index.php?topic=421081) may be of interest. It includes an example for a master and 2 slaves that can easily be extended to a larger number of slaves.
Hi. What kind of range are you looking for? I specialize in wireless sensor/actuator networks and I'd recommend my freakduino 900MHz (https://freaklabs.org/freakduino-standard/) and freakduino 900 MHz long range (https://freaklabs.org/products/freakduino-900mhz-long-range/). They're easy to program, can scale in range, and have low power and high reliability features. You can find tutorials here (https://freaklabs.org/documentation/tutorials/).