I have a raspberry pi setup at home. Having raspberry pi means I can keep it running and it can act as server. I can write complex code using high level language say in python.
For one of my project I had setup four 4-channel relays at four balconies of my home. I wanted to switch on a specific relay of a specific balcony. That will give me absolute control to switch on any device. I had setup a web-server on my raspberry-pi and my pi was already on the internet. So I could send the commands to raspberry-pi using my browser. Now somehow I had to sent this command from raspberry-pi to all my balconies so that I could switch on the relay.
I opted for Arudino to control the switching of relays. That means I have to send a high signal for a specific relay to a specific arudino. What are the options to send a digital high from pi to Aruduino.
Out of the following, my vote goes to Xbee.
Wired Connection
It will work, but I don’t want wires running in my home from pi to various balconies. It will be a big mess to manage.
wifi 802.11x
Since my raspberry pi is part of home area network. What if all the arduino boards could also be part of this network. That should do. I looked for it, but it turned out not so good option as it will need an expensive arduino shied.
https://www.sparkfun.com/products/11287
Bluetooth Modem
This is other option I looked for. Following modules are suppose to work as bluetooth to serial adapater. They can work as master and slave so technically two way communication between pi and arduino is possible. To communicate with a single arduino, I will need two such pieces. These looks like a good option, But there isn’t enough material available and I wasn’t confident about their range.
RF 434 Mhz
There are pretty cheap RF based transmitter and receiver. I bought a pair of them from ebay. They are cheap but pretty hard to get them working. Moreover they don’t seem to work inside home. To do a two way communication, we will need 2 such pairs.
Xbee
This is an excellent option. Initially I wasn’t sure about buying them because of the cost and because of the confusion about various models. But the other options weren’t working either. So out of frustration I bought two pieces of series 2 modules. Initial setup is a bit tricky and there is some learning curve, but believe me once that phase is done; these work like a charm.
