Today i soldered a RBBB (Really Bare Bones Board) kit. This is an Arduino-compatible board, but much smaller than for instance the Duemilanove.
A few weeks ago i realized that if i were actually going to use an Arduino somewhere in my house, i would want the board to be much smaller then the Duemilanove is.
That’s when i found the RBBB at Modern Devices. I ordered 2 RBBB’s, a USB-BUB and a USB cable.
Putting all pieces together was pretty straightforward, the instructions were very clear and within an hour i had my first RBBB up and running it’s first sketch.
The dimensions of the RBBB are 15 x 76 mm, but you can make it even smaller if you can live without the power jack or even the voltage regulator.
Just cut a piece off of the right side of the board: 15 x 57 mm is the minimal board size.
Another thing i found out is that the ATMega microcontroller will run fine at 3.3V, which seems to be a better choice then 5V when you want to connect all kinds of sensors to it.
For that i will soon get me some JeeNodes which seem to be specifically designed for 3.3V.
One thing i’m still a bit worried about is what to choose for communication; 433, 868 MHz or XBee?
433 MHz is where i already have a lot of sensors transmitting; sometimes sensor signals are lost, which is not a big deal for things like temperature sensors, but if i want my ATMega to lock the front door, i don’t think 433 MHz is a good choice.
The same goes for 868 MHz: that’s the frequency on which all my security sensors are operating; i don’t want to over-populate that frequency either.
XBee module on 2.4 GHz then? Maybe.. but will i be able to reduce power consumption of ATMega + XBee to an acceptable level so that i won’t have to change batteries every week? 🙁 There’s still a lot of work to do…