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As I have several projects down the line I had to start somewhere. In this project I will build a wireless temperature sensor system. The main goal of the project is to be able to see the temperatures in several rooms at home when I'm away. I will also have a temperature node outside.
To manage this I will use Moteinos. I spent some time trying to find the best hardware for this. Before I decided I looked at XBee, JeeNode, PanStamp among others. They all have their uses, but I felt that Moteino would do the job best for this specific project. For later projects I just might try out the PanStamp as well.
Moteino is a small, low power, battery operated wireless Arduino Uno. The price shouldn't scare you either. The basic Moteino with a radio module is priced at about $20. They are programmed the same way as any other Arduino, but you will need a FTDI-Adapter or buy the Moteino-USB. And of course, you will need at least two: One as a transmitter and one as a receiver. Head over to the LowPowerLab Store and have a look.
To be able to read off the temperatures when I'm not at home, I have to connect this to The Internet somehow. I was first thinking of using an Arduino with an Ethernet shield. But the thing is that I have a Windows server running at home which again run a CentOS Linux server in a VirtualBox environment. I use this mainly for automatic backup of the web server at work.
So I decided to use the same Linux to do the readings from the base station. The base station will be a Moteino programmed as a wireless receiver for the other Moteino (temperature) nodes. I will connect the Moteino to the server via a plain USB micro cable. On the Linux I will use a Perl script to read the /dev/tty* port from the Moteino and upload the data to Thingspeak.
The web page
Finally I will need a place to read out the temperatures. I will publish the readings somewhere on this site. As I move along with more private projects, like home cameras and light switches/dimmers, I will obviously have to restrict access to the readings. I will however create a demo page resembling my own private control page, so you get an idea of how it all works.
The web page - Readings
I haven't decided how I will present the readings on the web page yet, but I'm guessing it will be some kind of chart together with the current temperature. The web interface will be posted as a part of the project and will be available from this page.
So, now what?
I'm still waiting for some parts to start the project. In the meantime I'm experimenting with Perl to interface with the Moteino/Arduino via a serial cable. I will posts the progress of this project in parts. The links will be accessible from this page.